 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
jonboede(at)hotmail.com
Guest
|
 Posted: Thu Apr 29, 2021 6:14 pm Post subject: Housai engine question: compression check |
 |
|
One of the reasons your valve clearances change is because the cylinder is sitting lower, having lost part or all of the paper gasket between the cylinder and the case.
Grab the cylinder and firmly try to move it side to side and fore-back. Check if you see any motion along the 8 studs at the cylinder base or if you see a wet line along the base of the cylinder where it meets the engine case that changes in appearance as you move the cylinder.
Had your oil consumption been more than one quart an hour recently?
Otherwise, staking the valve is your best bet. Adjust it and if still getting air noises in the exhaust have an experienced mechanic show you the fine art of staking a valve. Plenty of times they will go from 0 to just fine after a good mallet whack.
Jon
| Quote: | On Apr 29, 2021, at 8:34 PM, Justin Drafts <draftsjust417(at)gmail.com> wrote:
Ok helpful gents and engine experts-
A fruitful sunny day spent(at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring/stem for cylinders #2 and #3.
Just so I'm understanding valvelash / clearance correctly:
- the 0.010-0.014" clearance mentionedis supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from greatcompression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders startingwith #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition,doing theirjob when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
<cyl #2 rocker arm, exhaust.jpg>
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
 |
draftsjust417(at)gmail.co
Guest
|
| Posted: Thu Apr 29, 2021 6:49 pm Post subject: Housai engine question: compression check |
|
|
Good info, thanks... did try the mallet whack repair, alas to no avail, at least not yet.Maybe I didn't rap it sharply enough?
Haven't seen any oil residue at cylinder bases, and thankfully the engine is only drinking ~1/2 quart oil per hour, not bad... thx for input! Justin
On Thu, Apr 29, 2021, 7:18 PM Jon Boede <jonboede(at)hotmail.com (jonboede(at)hotmail.com)> wrote:
| Quote: | One of the reasons your valve clearances change is because the cylinder is sitting lower, having lost part or all of the paper gasket between the cylinder and the case.
Grab the cylinder and firmly try to move it side to side and fore-back. Check if you see any motion along the 8 studs at the cylinder base or if you see a wet line along the base of the cylinder where it meets the engine case that changes in appearance as you move the cylinder.
Had your oil consumption been more than one quart an hour recently?
Otherwise, staking the valve is your best bet. Adjust it and if still getting air noises in the exhaust have an experienced mechanic show you the fine art of staking a valve. Plenty of times they will go from 0 to just fine after a good mallet whack.
Jon
| Quote: | On Apr 29, 2021, at 8:34 PM, Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
<cyl #2 rocker arm, exhaust.jpg>
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
kingcj6(at)aol.com
Guest
|
| Posted: Thu Apr 29, 2021 7:20 pm Post subject: Housai engine question: compression check |
|
|
MMO?
In a message dated 4/29/2021 7:50:21 PM Pacific Standard Time, draftsjust417(at)gmail.com writes:
| Quote: | Good info, thanks... did try the mallet whack repair, alas to no avail, at least not yet. Maybe I didn't rap it sharply enough?
Haven't seen any oil residue at cylinder bases, and thankfully the engine is only drinking ~1/2 quart oil per hour, not bad... thx for input! Justin
On Thu, Apr 29, 2021, 7:18 PM Jon Boede <jonboede(at)hotmail.com (jonboede(at)hotmail.com)> wrote:
| Quote: | One of the reasons your valve clearances change is because the cylinder is sitting lower, having lost part or all of the paper gasket between the cylinder and the case.
Grab the cylinder and firmly try to move it side to side and fore-back. Check if you see any motion along the 8 studs at the cylinder base or if you see a wet line along the base of the cylinder where it meets the engine case that changes in appearance as you move the cylinder.
Had your oil consumption been more than one quart an hour recently?
Otherwise, staking the valve is your best bet. Adjust it and if still getting air noises in the exhaust have an experienced mechanic show you the fine art of staking a valve. Plenty of times they will go from 0 to just fine after a good mallet whack.
Jon
| Quote: | On Apr 29, 2021, at 8:34 PM, Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote: Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentionedis supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>Also check the the air injector to make sure it is fully closed. It too has a very small valve inside of it about the size of a pencil eraser. If the little valve spring is broken or the valve remains open, it will of course affect the compression test.DennisA. Dennis Savarese334-546-8182www.yak-52.comOn 4/28/2021 11:58 PM, Justin Drafts wrote:> Good evening all->> A conundrum for you Housai engine experts; I need some advice to go fwd.> Doing the compression check today, I hit a weird wall.>> With a partner I was checking cylinders starting with #1 at top, going > CW when viewed from cockpit.> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2. > We got 0 psi on the pressure gauge.>> Checking the pressure tester/gauges/fittings/hose, all are fine and > perfectly functional.>> So we double checked the previous cylinder, which had just 10 min > prior tested at 74/80 psi... now it also> showed 0/80 psi. ??> No obvious air leaks from oil breather, carburetor, or exhaust stack; > no oil evident at bases of the cylinders;> the exhaust and intake stacks are good condition. I had flown the > plane earlier in the day w/o any negative> indications.>> Pulled the valve covers off to find the rocker arms, springs, etc in > great condition, doing their job when we> slowly turned the prop thru by hand.>> Stuck valves?>> We tried the "rope trick" to slip a nylon cord into the cylinder thru > the open sparkplug hole, then gently run> the piston up to TDC to try to reseat the possibly stuck-open valves. > As yet, no help.>> Fishing for advice & thoughts... what are we missing?> I've never seen a 0/80 psi reading... a bad piston ring or bad valve, > should have SOME psi indication 30~60psi.>> Thoughts? Pointers?> Thanks--->> Justin Drafts> N280NC===========List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List===========FORUMS -eferrer" target="_blank">http://forums.matronics.com===========WIKI -errer" target="_blank">http://wiki.matronics.com===========b Site - -Matt Dralle, List Admin.rel="noreferrer" target="_blank">http://www.matronics.com/contribution=========== |
<cyl #2 rocker arm, exhaust.jpg>
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
Clouddog
Joined: 02 Jun 2016
Posts: 119
Location: Lebanon, TN
|
| Posted: Fri Apr 30, 2021 3:44 am Post subject: Housai engine question: compression check |
|
|
Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
pennington.construction.i
Guest
|
| Posted: Fri Apr 30, 2021 3:55 am Post subject: Housai engine question: compression check |
|
|
Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Fri Apr 30, 2021 6:17 am Post subject: Housai engine question: compression check |
|
|
All good info gents, thanks & very very much appreciated... stay tuned!
J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <
pennington.construction.inc.1(at)gmail.com> wrote:
[quote] Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you
haven’t done that yet. How you use the feeler gauge is important. As
taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am
sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink
a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com> wrote:
> Sticking valves happen. We have all had them. The danger is when you let
> them go you may eventually burn the valve and then you have another issue
> to deal with. When you pull through in a perfect world you should not hear
> any air coming from exhaust or carb. Sometimes a small amount may come
> through and after a flight it should normally go away if not, then you need
> to address it with a rubber mallet, or spinning the valve (lapping). We can
> get into discussing Marvel Mystery Oil in the fuel and/or oil but that is
> another bag of opinions
>
> Greg "Clouddog" Wrobel
>
> On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com>
> wrote:
>
>> Ok helpful gents and engine experts-
>> A fruitful sunny day spent (at) hangar with the suspect cylinders.
>>
>> Checked the small starting air valve: definitely in good working order
>> and closing as appropriate.
>>
>> Pulling off rocker covers and watching the rocker arm and valve springs,
>> I see there is
>> no gap at TDC between the rocker arm and top of the spring /stem for
>> cylinders #2 and #3.
>>
>> Just so I'm understanding valve lash / clearance correctly:
>> - the 0.010-0.014" clearance mentioned is supposed to be here at the
>> red circle in the
>> attached pic, correct? (While the stem is at its highest point of
>> travel/valve fully seated/TDC...)
>> -adjusting this clearance/lash requires turning the large adjustment
>> screw at the green arrow, correct?
>>
>> Based on the air I hear escaping the exhaust stack, I suspect the
>> exhaust valves are sticking or
>> otherwise remaining open.
>>
>> Not sure how I went from great compression #'s last year to 0/80 psi
>> this year, but very little surprises
>> me in maintenance anymore.
>>
>> Thoughts gents?
>> Thanks- Justin
>>
>> On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <
>> dsavarese0812(at)bellsouth.net> wrote:
>>
>>>
>>> dsavarese0812(at)bellsouth.net>
>>>
>>> Also check the the air injector to make sure it is fully closed. It
>>> too
>>> has a very small valve inside of it about the size of a pencil eraser.
>>> If the little valve spring is broken or the valve remains open, it will
>>> of course affect the compression test.
>>> Dennis
>>>
>>> A. Dennis Savarese
>>> 334-546-8182
>>> www.yak-52.com
>>>
>>> On 4/28/2021 11:58 PM, Justin Drafts wrote:
>>> > Good evening all-
>>> >
>>> > A conundrum for you Housai engine experts; I need some advice to go
>>> fwd.
>>> > Doing the compression check today, I hit a weird wall.
>>> >
>>> > With a partner I was checking cylinders starting with #1 at top,
>>> going
>>> > CW when viewed from cockpit.
>>> > All #'s were good (avg 75/80 psi), until I got the last cylinder, #2
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Fri Apr 30, 2021 1:02 pm Post subject: Housai engine question: compression check |
|
|
Fast question... what's the req'd torque in the rocker arms' jam nuts ?What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned!J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
dsavarese0812(at)bellsout
Guest
|
| Posted: Fri Apr 30, 2021 5:53 pm Post subject: Housai engine question: compression check |
|
|
No torque spec that I’m aware of. Tighten securely using proper 17 mm socket wrench or a properly fitted box end wrench. Don’t use an open end wrench. Very likely you’ll round off the corners of the hex nut. Dennis .
Sent from my iPhone
| Quote: | On Apr 30, 2021, at 5:04 PM, Justin Drafts <draftsjust417(at)gmail.com> wrote:
Fast question... what's the req'd torque in the rocker arms' jam nuts ?What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned!J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
desmor944
Joined: 31 Jul 2018
Posts: 2
Location: Cape Cod, MA
|
| Posted: Sat May 01, 2021 6:38 am Post subject: Housai engine question: compression check |
|
|
Justin,
As always, Walt is spot on with the advice below.
One suggestion to make this task a bit easier and more accurate is to use a step feeler gauge when setting the clearance. The thickness of each blade is reduced by 0.002 inch at the end; making it a GO / NO-GO gauge. For a 0.014 clearance, you would use the 0.013 / 0.015 blade. Set correctly, the thinner portion of the blade will slide smoothly under the rocker arm and then stop at the thicker portion. Craftsman appears to have discontinued the set shown in the photo but Stanley Proto and others are available on Amazon.
Rich Desmond
--
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
| Description: |
|
| Filesize: |
1.57 MB |
| Viewed: |
5354 Time(s) |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Sat May 01, 2021 7:25 am Post subject: Housai engine question: compression check |
|
|
Hey Walt, thanks for all the details...
Ya, looking at the engine yesterday, it *seems* like a straightforward
operation, with the right tools.
I'm at:
*draftsjust417(at)gmail.com <draftsjust417(at)gmail.com>*
*843-224-9040*
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca> wrote:
[quote] Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts.
However there are two special tools for this purpose. The wrench is an
open socket style with a fixed handle used in combination with a right
angle screw driver that is positioned through the open socket to hold your
adjustment position while tightening
.
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole
operation should be done four times. With the P &W R1340 that is a must!
due to something called a floating cam ring. These engines do not have
that problem but if you If you find any significant changes do it again.
It is a straight forward operation for the intake valve but the engine
should be rotated slightly to provide clearance of the wrench for the
exhaust nut. This would apply for any socket type wrench. If that
clearance is not obtained there is a real possibility of damage to the nut.
I expect you have noticed there is a light spring pressure that closes up
the valve clearance. At first glance one may think there is no clearance
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
fishmouth500
Joined: 07 Apr 2015
Posts: 43
Location: Southern California
|
| Posted: Sat May 01, 2021 8:08 am Post subject: Housai engine question: compression check |
|
|
Repro valve adjust tools available
https://www.theyakcollection.com/store/p297/Valve_adjusting_tool_set%2C_M14-P%2FHoussai_-_Repro.html
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Hey Walt, thanks for all the details...Ya, looking at the engine yesterday, it seems like a straightforward operation, with the right tools.
I'm at:
draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)
843-224-9040
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts. However there are two special tools for this purpose. The wrench is an open socket style with a fixed handle used in combination with a right angle screw driver that is positioned through the open socket to hold your adjustment position while tightening .
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole operation should be done four times. With the P &W R1340 that is a must! due to something called a floating cam ring. These engines do not have that problem but if you If you find any significant changes do it again.
It is a straight forward operation for the intake valve but the engine should be rotated slightly to provide clearance of the wrench for the exhaust nut. This would apply for any socket type wrench. If that clearance is not obtained there is a real possibility of damage to the nut.
I expect you have noticed there is a light spring pressure that closes up the valve clearance. At first glance one may think there is no clearance. This spring is at the opposite end of the push rod and has nothing to do with valve clearance in operation. It’s purpose is to keep the cam roller in constant rolling contact with the cam ring to reduce wear. You can see this spring operation by pressing the nut end of the rocker with your finger.
The feeler guage should be used at right angles across the width of the rocker box. That will appear obvious since using in a fore & aft manner will introduce interference and likely produce errors.
I have found over the years that the exhaust valves tend to tighten over time and as a result I use 0.012” for the intake and 0.014” for the exhaust whether Huosai or M14P.
I will send you some photos of the proper tools tomorrow. Will need your phone #. Mine is 250-485-8698.
Cheers;
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Friday, April 30, 2021 2:01 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
--
www.theyakcollection.com
619 933-2571
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
fishmouth500
Joined: 07 Apr 2015
Posts: 43
Location: Southern California
|
| Posted: Sat May 01, 2021 9:06 am Post subject: Housai engine question: compression check |
|
|
No problem at all Walt, glad to be part of the discussion 👍👍
On Sat, May 1, 2021 at 10:03 AM Walter Lannon <wlannon(at)shaw.ca> wrote:
[quote] Hi John;
Please accept my apology for forgetting your superb tooling. At 88 my
memory is certainly not what it once was but will try to do better in
future.
Best;
Walt
*From:* John Warwick <john.warwick1(at)gmail.com>
*Sent:* Saturday, May 01, 2021 9:07 AM
*To:* yak-list(at)matronics.com
*Subject:* Re: Re: Housai engine question: compression check
Repro valve adjust tools available
https://www.theyakcollection.com/store/p297/Valve_adjusting_tool_set%2C_M14-P%2FHoussai_-_Repro.html
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com>
wrote:
> Hey Walt, thanks for all the details...
> Ya, looking at the engine yesterday, it *seems* like a straightforward
> operation, with the right tools.
>
> I'm at:
> *draftsjust417(at)gmail.com <draftsjust417(at)gmail.com>*
> *843-224-9040*
>
> Advice is very much appreciated...
>
> On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca> wrote:
>
>> Hi Justin;
>>
>> I too have not seen a specific torque value for the rocker arm nuts.
>> However there are two special tools for this purpose. The wrench is an
>> open socket style with a fixed handle used in combination with a right
>> angle screw driver that is positioned through the open socket to hold your
>> adjustment position while tightening
>> .
>> The operating word is as tight as you can get it with this wrench.
>>
>> Re-check all clearances after tightening. Technically this whole
>> operation should be done four times. With the P &W R1340 that is a must!
>> due to something called a floating cam ring. These engines do not have
>> that problem but if you If you find any significant changes do it again
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Sat May 01, 2021 9:37 am Post subject: Housai engine question: compression check |
|
|
Great tools John!Very helpful pix as well... ages back I'd ordered a batch of poorer-quality PLAAF tools, it's good to see better ones avail.
Btw, have you ever seen the proper torque for the rocker arm jam nuts?
(I can't find any such reference in my maint manuals...)
On Sat, May 1, 2021, 10:11 AM John Warwick <john.warwick1(at)gmail.com (john.warwick1(at)gmail.com)> wrote:
| Quote: | No problem at all Walt, glad to be part of the discussion 👍👍
On Sat, May 1, 2021 at 10:03 AM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi John;
Please accept my apology for forgetting your superb tooling. At 88 my memory is certainly not what it once was but will try to do better in future.
Best;
Walt
From: John Warwick (john.warwick1(at)gmail.com)
Sent: Saturday, May 01, 2021 9:07 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Repro valve adjust tools available
https://www.th_Repro.html
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Hey Walt, thanks for all the details... Ya, looking at the engine yesterday, it seems like a straightforward operation, with the right tools.
I'm at:
draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)
843-224-9040
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts. However there are two special tools for this purpose. The wrench is an open socket style with a fixed handle used in combination with a right angle screw driver that is positioned through the open socket to hold your adjustment position while tightening .
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole operation should be done four times. With the P &W R1340 that is a must! due to something called a floating cam ring. These engines do not have that problem but if you If you find any significant changes do it again.
It is a straight forward operation for the intake valve but the engine should be rotated slightly to provide clearance of the wrench for the exhaust nut. This would apply for any socket type wrench. If that clearance is not obtained there is a real possibility of damage to the nut.
I expect you have noticed there is a light spring pressure that closes up the valve clearance. At first glance one may think there is no clearance. This spring is at the opposite end of the push rod and has nothing to do with valve clearance in operation. It’s purpose is to keep the cam roller in constant rolling contact with the cam ring to reduce wear. You can see this spring operation by pressing the nut end of the rocker with your finger.
The feeler guage should be used at right angles across the width of the rocker box. That will appear obvious since using in a fore & aft manner will introduce interference and likely produce errors.
I have found over the years that the exhaust valves tend to tighten over time and as a result I use 0.012” for the intake and 0.014” for the exhaust whether Huosai or M14P.
I will send you some photos of the proper tools tomorrow. Will need your phone #. Mine is 250-485-8698.
Cheers;
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Friday, April 30, 2021 2:01 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
--
www.theyakcollection.com
619 933-2571
|
--
www.theyakcollection.com
619 933-2571
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
pennington.construction.i
Guest
|
| Posted: Sat May 01, 2021 9:45 am Post subject: Housai engine question: compression check |
|
|
Richard Goode.
If you are watching this. Is there a torque spec for the jamb nut for the rocker arm. ???
If anyone would know it’s the guy who rebuilds these engines.
Thanks
Mark
N621CJ
On Sat, May 1, 2021 at 1:41 PM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Great tools John!Very helpful pix as well... ages back I'd ordered a batch of poorer-quality PLAAF tools, it's good to see better ones avail.
Btw, have you ever seen the proper torque for the rocker arm jam nuts?
(I can't find any such reference in my maint manuals...)
On Sat, May 1, 2021, 10:11 AM John Warwick <john.warwick1(at)gmail.com (john.warwick1(at)gmail.com)> wrote:
| Quote: | No problem at all Walt, glad to be part of the discussion 👍👍
On Sat, May 1, 2021 at 10:03 AM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi John;
Please accept my apology for forgetting your superb tooling. At 88 my memory is certainly not what it once was but will try to do better in future.
Best;
Walt
From: John Warwick (john.warwick1(at)gmail.com)
Sent: Saturday, May 01, 2021 9:07 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Repro valve adjust tools available
https://www.th_Repro.html
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Hey Walt, thanks for all the details... Ya, looking at the engine yesterday, it seems like a straightforward operation, with the right tools.
I'm at:
draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)
843-224-9040
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts. However there are two special tools for this purpose. The wrench is an open socket style with a fixed handle used in combination with a right angle screw driver that is positioned through the open socket to hold your adjustment position while tightening .
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole operation should be done four times. With the P &W R1340 that is a must! due to something called a floating cam ring. These engines do not have that problem but if you If you find any significant changes do it again.
It is a straight forward operation for the intake valve but the engine should be rotated slightly to provide clearance of the wrench for the exhaust nut. This would apply for any socket type wrench. If that clearance is not obtained there is a real possibility of damage to the nut.
I expect you have noticed there is a light spring pressure that closes up the valve clearance. At first glance one may think there is no clearance. This spring is at the opposite end of the push rod and has nothing to do with valve clearance in operation. It’s purpose is to keep the cam roller in constant rolling contact with the cam ring to reduce wear. You can see this spring operation by pressing the nut end of the rocker with your finger.
The feeler guage should be used at right angles across the width of the rocker box. That will appear obvious since using in a fore & aft manner will introduce interference and likely produce errors.
I have found over the years that the exhaust valves tend to tighten over time and as a result I use 0.012” for the intake and 0.014” for the exhaust whether Huosai or M14P.
I will send you some photos of the proper tools tomorrow. Will need your phone #. Mine is 250-485-8698.
Cheers;
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Friday, April 30, 2021 2:01 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Sat May 01, 2021 9:50 am Post subject: Housai engine question: compression check |
|
|
Good info, esp on open ended wrench caution... Stay tuned! J.
On Fri, Apr 30, 2021, 6:57 PM Anthony Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | No torque spec that I’m aware of. Tighten securely using proper 17 mm socket wrench or a properly fitted box end wrench. Don’t use an open end wrench. Very likely you’ll round off the corners of the hex nut. Dennis .
Sent from my iPhone
| Quote: | On Apr 30, 2021, at 5:04 PM, Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
Fast question... what's the req'd torque in the rocker arms' jam nuts ?What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned!J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
> Good evening all-
>
> A conundrum for you Housai engine experts; I need some advice to go fwd.
> Doing the compression check today, I hit a weird wall.
>
> With a partner I was checking cylinders starting with #1 at top, going
> CW when viewed from cockpit.
> All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
> We got 0 psi on the pressure gauge.
>
> Checking the pressure tester/gauges/fittings/hose, all are fine and
> perfectly functional.
>
> So we double checked the previous cylinder, which had just 10 min
> prior tested at 74/80 psi.... now it also
> showed 0/80 psi. ??
> No obvious air leaks from oil breather, carburetor, or exhaust stack;
> no oil evident at bases of the cylinders;
> the exhaust and intake stacks are good condition. I had flown the
> plane earlier in the day w/o any negative
> indications.
>
> Pulled the valve covers off to find the rocker arms, springs, etc in
> great condition, doing their job when we
> slowly turned the prop thru by hand.
>
> Stuck valves?
>
> We tried the "rope trick" to slip a nylon cord into the cylinder thru
> the open sparkplug hole, then gently run
> the piston up to TDC to try to reseat the possibly stuck-open valves.
> As yet, no help.
>
> Fishing for advice & thoughts... what are we missing?
> I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
> should have SOME psi indication 30~60psi.
>
> Thoughts? Pointers?
> Thanks---
>
> Justin Drafts
> N280NC
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
fishmouth500
Joined: 07 Apr 2015
Posts: 43
Location: Southern California
|
| Posted: Sat May 01, 2021 10:22 am Post subject: Housai engine question: compression check |
|
|
I haven’t, but I tend to agree with Walt, the length of the wrench is a good index to what they were expecting from Atilla the Valve lash avenger👍👍
On Sat, May 1, 2021 at 10:41 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Great tools John!Very helpful pix as well.. ages back I'd ordered a batch of poorer-quality PLAAF tools, it's good to see better ones avail.
Btw, have you ever seen the proper torque for the rocker arm jam nuts?
(I can't find any such reference in my maint manuals...)
On Sat, May 1, 2021, 10:11 AM John Warwick <john.warwick1(at)gmail.com (john.warwick1(at)gmail.com)> wrote:
| Quote: | No problem at all Walt, glad to be part of the discussion 👍👍
On Sat, May 1, 2021 at 10:03 AM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi John;
Please accept my apology for forgetting your superb tooling. At 88 my memory is certainly not what it once was but will try to do better in future.
Best;
Walt
From: John Warwick (john.warwick1(at)gmail.com)
Sent: Saturday, May 01, 2021 9:07 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Repro valve adjust tools available
https://www.th_Repro.html
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Hey Walt, thanks for all the details... Ya, looking at the engine yesterday, it seems like a straightforward operation, with the right tools.
I'm at:
draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)
843-224-9040
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts. However there are two special tools for this purpose. The wrench is an open socket style with a fixed handle used in combination with a right angle screw driver that is positioned through the open socket to hold your adjustment position while tightening .
The operating word is as tight as you can get it with this wrench.
Re-check all clearances after tightening. Technically this whole operation should be done four times. With the P &W R1340 that is a must! due to something called a floating cam ring. These engines do not have that problem but if you If you find any significant changes do it again.
It is a straight forward operation for the intake valve but the engine should be rotated slightly to provide clearance of the wrench for the exhaust nut. This would apply for any socket type wrench. If that clearance is not obtained there is a real possibility of damage to the nut.
I expect you have noticed there is a light spring pressure that closes up the valve clearance. At first glance one may think there is no clearance. This spring is at the opposite end of the push rod and has nothing to do with valve clearance in operation. It’s purpose is to keep the cam roller in constant rolling contact with the cam ring to reduce wear. You can see this spring operation by pressing the nut end of the rocker with your finger.
The feeler guage should be used at right angles across the width of the rocker box. That will appear obvious since using in a fore & aft manner will introduce interference and likely produce errors.
I have found over the years that the exhaust valves tend to tighten over time and as a result I use 0.012” for the intake and 0.014” for the exhaust whether Huosai or M14P.
I will send you some photos of the proper tools tomorrow. Will need your phone #. Mine is 250-485-8698.
Cheers;
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Friday, April 30, 2021 2:01 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
|
|
|
--
www.theyakcollection.com
619 933-2571
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
richard.goode(at)russiana
Guest
|
| Posted: Sun May 02, 2021 2:22 am Post subject: Housai engine question: compression check |
|
|
I don't think there is a specific torque figure, and I couldn't see one in the standard engine manual!
Richard
RICHARD GOODE AEROBATICS
Rhodds Farm, Lyonshall, Hereford, HR5 3LW, UK
Tel: +44 (0)1544 340120 Fax: +44 (0)1544 340129
e-mail: richard.goode(at)russianaeros.com <mailto:richard.goode(at)russianaeros.com>
<http://www.russianaeros.com> www.russianaeros.com
WORLD LEADERS IN RUSSIAN SPORTING AIRCRAFT & ENGINES
In partnership with Aerometal Kft, Hungary.
From: owner-yak-list-server(at)matronics.com <owner-yak-list-server(at)matronics.com> On Behalf Of Mark Pennington
Sent: 01 May 2021 18:45
To: yak-list(at)matronics.com
Subject: Re: Re: Housai engine question: compression check
Richard Goode.
If you are watching this. Is there a torque spec for the jamb nut for the rocker arm. ???
If anyone would know it’s the guy who rebuilds these engines.
Thanks
Mark
N621CJ
On Sat, May 1, 2021 at 1:41 PM Justin Drafts <draftsjust417(at)gmail.com <mailto:draftsjust417(at)gmail.com> > wrote:
Great tools John!
Very helpful pix as well... ages back I'd ordered a batch of poorer-quality PLAAF tools, it's good to see better ones avail.
Btw, have you ever seen the proper torque for the rocker arm jam nuts?
(I can't find any such reference in my maint manuals...)
On Sat, May 1, 2021, 10:11 AM John Warwick <john.warwick1(at)gmail.com <mailto:john.warwick1(at)gmail.com> > wrote:
No problem at all Walt, glad to be part of the discussion 👍👍
On Sat, May 1, 2021 at 10:03 AM Walter Lannon <wlannon(at)shaw.ca <mailto:wlannon(at)shaw.ca> > wrote:
Hi John;
Please accept my apology for forgetting your superb tooling. At 88 my memory is certainly not what it once was but will try to do better in future.
Best;
Walt
From: John Warwick <mailto:john.warwick1(at)gmail.com>
Sent: Saturday, May 01, 2021 9:07 AM
To: yak-list(at)matronics.com <mailto:yak-list(at)matronics.com>
Subject: Re: Re: Housai engine question: compression check
Repro valve adjust tools available
https://www.th_Repro.html <https://www.theyakcollection.com/store/p297/Valve_adjusting_tool_set%2C_M14-P%2FHoussai_-_Repro.html>
On Sat, May 1, 2021 at 8:30 AM Justin Drafts <draftsjust417(at)gmail.com <mailto:draftsjust417(at)gmail.com> > wrote:
Hey Walt, thanks for all the details...
Ya, looking at the engine yesterday, it seems like a straightforward operation, with the right tools.
I'm at:
draftsjust417(at)gmail.com <mailto:draftsjust417(at)gmail.com>
843-224-9040
Advice is very much appreciated...
On Fri, Apr 30, 2021, 10:04 PM Walter Lannon <wlannon(at)shaw.ca <mailto:wlannon(at)shaw.ca> > wrote:
Hi Justin;
I too have not seen a specific torque value for the rocker arm nuts. However there are two special tools for this purpose. The wrench is an open socket style with a fixed handle used in combination with a right angle screw driver that is positioned through the open socket to hold your adjustment position while tightening
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Sun May 02, 2021 6:45 am Post subject: Housai engine question: compression check |
|
|
Sounds good, much appreciated!
Grateful to have the time off now to
wade into this new area.
I'll plan on, once airworthy, to go back under the valve covers and check these nuts' security after 5 hours.
Justin
On Sat, May 1, 2021, 10:01 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Justin et al;
Having likely adjusted a few thousand radial engine valves over the past 70 years or so I can truthfully say I have never had occasion to use a torque wrench for this function.
Just went through the torque specification sections of the P&W R985/R1340 Overhaul Manual and found no recommendation whatsoever in this regard. Will check out the P&W Mtce. manual and corresponding FAA manuals next trip to hangar.
Not really surprised as this type of joint perfectly meets the definition of a “jamb” nut lock! Will check out the FAA guidance and get back!
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Saturday, May 01, 2021 10:49 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Good info, esp on open ended wrench caution... Stay tuned! J.
On Fri, Apr 30, 2021, 6:57 PM Anthony Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | No torque spec that I’m aware of. Tighten securely using proper 17 mm socket wrench or a properly fitted box end wrench. Don’t use an open end wrench. Very likely you’ll round off the corners of the hex nut. Dennis .
Sent from my iPhone
| Quote: | On Apr 30, 2021, at 5:04 PM, Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
draftsjust417(at)gmail.co
Guest
|
| Posted: Thu May 13, 2021 7:51 am Post subject: Housai engine question: compression check |
|
|
Good morning all-
Update to the compression check, w/ good news.
Checking & resetting the valve clearances (0.3/0.4 mm) on all 9 cylinders did the trick;
the lowest # I got on all compression checks was a comfortable 73/80 psi. Latest takeoff
felt like I had a bit more giddyup as well, no surprise.
THANKS ALL for the good advice, much appreciated.
Justin
N280NC
On Sat, May 1, 2021 at 10:01 PM Walter Lannon <wlannon(at)shaw.ca (wlannon(at)shaw.ca)> wrote:
| Quote: | Justin et al;
Having likely adjusted a few thousand radial engine valves over the past 70 years or so I can truthfully say I have never had occasion to use a torque wrench for this function.
Just went through the torque specification sections of the P&W R985/R1340 Overhaul Manual and found no recommendation whatsoever in this regard. Will check out the P&W Mtce. manual and corresponding FAA manuals next trip to hangar.
Not really surprised as this type of joint perfectly meets the definition of a “jamb” nut lock! Will check out the FAA guidance and get back!
Walt
From: Justin Drafts (draftsjust417(at)gmail.com)
Sent: Saturday, May 01, 2021 10:49 AM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Re: Housai engine question: compression check
Good info, esp on open ended wrench caution... Stay tuned! J.
On Fri, Apr 30, 2021, 6:57 PM Anthony Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | No torque spec that I’m aware of. Tighten securely using proper 17 mm socket wrench or a properly fitted box end wrench. Don’t use an open end wrench. Very likely you’ll round off the corners of the hex nut. Dennis .
Sent from my iPhone
| Quote: | On Apr 30, 2021, at 5:04 PM, Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
Fast question... what's the req'd torque in the rocker arms' jam nuts ? What # has everyone used?
Thanks again all--
Justin
On Fri, Apr 30, 2021, 7:16 AM Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | All good info gents, thanks & very very much appreciated... stay tuned! J
On Fri, Apr 30, 2021, 4:59 AM Mark Pennington <pennington.construction.inc.1(at)gmail.com (pennington.construction.inc.1(at)gmail.com)> wrote:
| Quote: | Justin
You are right about adjusting the valves. You photo is accurate.
I would talk to someone at length about the step by step procedure if you haven’t done that yet. How you use the feeler gauge is important. As taught to me by others.
I would suggest fix the sticking valve before you adjust anything. I am sure you are aware of that info.
And Yes. MMO is a very wide and varied discussion for sure. Me, I drink a pint before every flight. LOL.
Mark
N621CJ.
On Fri, Apr 30, 2021 at 7:48 AM Greg Wrobel <clouddog22(at)gmail.com (clouddog22(at)gmail.com)> wrote:
| Quote: | Sticking valves happen. We have all had them. The danger is when you let them go you may eventually burn the valve and then you have another issue to deal with. When you pull through in a perfect world you should not hear any air coming from exhaust or carb. Sometimes a small amount may come through and after a flight it should normally go away if not, then you need to address it with a rubber mallet, or spinning the valve (lapping). We can get into discussing Marvel Mystery Oil in the fuel and/or oil but that is another bag of opinions
Greg "Clouddog" Wrobel
On Thu, Apr 29, 2021, 21:34 Justin Drafts <draftsjust417(at)gmail.com (draftsjust417(at)gmail.com)> wrote:
| Quote: | Ok helpful gents and engine experts-
A fruitful sunny day spent (at) hangar with the suspect cylinders.
Checked the small starting air valve: definitely in good working order and closing as appropriate.
Pulling off rocker covers and watching the rocker arm and valve springs, I see there is
no gap at TDC between the rocker arm and top of the spring /stem for cylinders #2 and #3.
Just so I'm understanding valve lash / clearance correctly:
- the 0.010-0.014" clearance mentioned is supposed to be here at the red circle in the
attached pic, correct? (While the stem is at its highest point of travel/valve fully seated/TDC...)
-adjusting this clearance/lash requires turning the large adjustment screw at the green arrow, correct?
Based on the air I hear escaping the exhaust stack, I suspect the exhaust valves are sticking or
otherwise remaining open.
Not sure how I went from great compression #'s last year to 0/80 psi this year, but very little surprises
me in maintenance anymore.
Thoughts gents?
Thanks- Justin
On Thu, Apr 29, 2021 at 5:09 AM A. Dennis Savarese <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)> wrote:
| Quote: | --> Yak-List message posted by: "A. Dennis Savarese" <dsavarese0812(at)bellsouth.net (dsavarese0812(at)bellsouth.net)>
Also check the the air injector to make sure it is fully closed. It
too
has a very small valve inside of it about the size of a pencil eraser.
If the little valve spring is broken or the valve remains open, it will
of course affect the compression test.
Dennis
A. Dennis Savarese
334-546-8182
www.yak-52.com
On 4/28/2021 11:58 PM, Justin Drafts wrote:
| Quote: | Good evening all-
A conundrum for you Housai engine experts; I need some advice to go fwd.
Doing the compression check today, I hit a weird wall.
With a partner I was checking cylinders starting with #1 at top, going
CW when viewed from cockpit.
All #'s were good (avg 75/80 psi), until I got the last cylinder, #2.
We got 0 psi on the pressure gauge.
Checking the pressure tester/gauges/fittings/hose, all are fine and
perfectly functional.
So we double checked the previous cylinder, which had just 10 min
prior tested at 74/80 psi.... now it also
showed 0/80 psi. ??
No obvious air leaks from oil breather, carburetor, or exhaust stack;
no oil evident at bases of the cylinders;
the exhaust and intake stacks are good condition. I had flown the
plane earlier in the day w/o any negative
indications.
Pulled the valve covers off to find the rocker arms, springs, etc in
great condition, doing their job when we
slowly turned the prop thru by hand.
Stuck valves?
We tried the "rope trick" to slip a nylon cord into the cylinder thru
the open sparkplug hole, then gently run
the piston up to TDC to try to reseat the possibly stuck-open valves.
As yet, no help.
Fishing for advice & thoughts... what are we missing?
I've never seen a 0/80 psi reading... a bad piston ring or bad valve,
should have SOME psi indication 30~60psi.
Thoughts? Pointers?
Thanks---
Justin Drafts
N280NC
|
===========
List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?Yak-List
===========
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
===========
WIKI -
errer" target="_blank">http://wiki.matronics.com
===========
b Site -
-Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
===========
|
|
|
|
|
|
|
|
| | - The Matronics Yak-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Yak-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
