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cd001633(at)mindspring.co
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 Posted: Mon Jun 03, 2013 4:23 am Post subject: Engine Start Mystery |
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This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami FL
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bwade154(at)yahoo.com
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| Posted: Mon Jun 03, 2013 8:26 am Post subject: Engine Start Mystery |
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Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com>
To: yak-list(at)matronics.com
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
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[quote][b]
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cjpilot710(at)aol.com
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| Posted: Mon Jun 03, 2013 4:53 pm Post subject: Engine Start Mystery |
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I agree with Bill if you had a valve stuck open, the engine would not kick passed that cylinder. I had this happen on the HS6a with a burnt exhaust valve. As for the super rotation - - - I am totally stumped. Pappy
In a message dated 6/3/2013 12:26:32 P.M. Eastern Daylight Time, bwade154(at)yahoo.com writes:
| Quote: | Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com>
To: yak-list(at)matronics.com
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
|
[quote][b]
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pfstelwagon(at)earthlink.
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| Posted: Mon Jun 03, 2013 6:01 pm Post subject: Engine start mystery |
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I wonder, since the M14 is usually started with the mags off until it fires if the engine was actually running on the shower of sparks in the hot cylinder environment. The initial cylinder pull through with the normal compression then the soft cylinder may have been the cylinder actually burning residual fuel.
That would be similar to the early days of emission controls when the engines tended to run on after shut down. This was due to the high heat and the carburetor allowing fuel into the engine. Remember the shower of sparks is retarded and with the hot engine it may have actually been running.
Would have been interesting if the mags had been turned on while it was spinning fast, probably would have started fine.
[quote][b]
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viperdoc(at)mindspring.co
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| Posted: Mon Jun 03, 2013 6:53 pm Post subject: Engine Start Mystery |
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A freek alignment of the compression rings with the oil scavenge rings comes to mind. As possible air start valve leaking. Any oil spray around the bases of your air start valves? loose spark plugs will allow air leaking also. Not likely I know. Check the ceramic bases on your plugs also. You could have blown the cores on a few of the plugs to if they are RU or Chinese. A fully blown core will be a blow torch I know but not some that are cracked.
Just a few more thoughts on the the subject.
Doc`
Sent from my iPad
On Jun 3, 2013, at 7:50 PM, cjpilot710(at)aol.com (cjpilot710(at)aol.com) wrote:
[quote] I agree with Bill if you had a valve stuck open, the engine would not kick passed that cylinder. I had this happen on the HS6a with a burnt exhaust valve. As for the super rotation - - - I am totally stumped. Pappy
In a message dated 6/3/2013 12:26:32 P.M. Eastern Daylight Time, bwade154(at)yahoo.com (bwade154(at)yahoo.com) writes:
| Quote: | Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
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| Quote: |
===================================
//www.matronics.com/Navigator?Yak-List
===================================
cs.com
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matronics.com/contribution
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cd001633(at)mindspring.co
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| Posted: Mon Jun 03, 2013 7:02 pm Post subject: Engine Start Mystery |
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Thanks Pappy!
I am scratching my head on this fast rotation issue  BIG Time! I may have not primed enough thinking of a warm engine (only two strokes, which were normally enough) but let’s say not enough priming  in this case –
But why the fast rotation? Air Tank Pressure was 42 ATM on the first fast spinning attempt and 38 on the second fast spinning attempt.
Third attempt was successful with additional Priming and slower (normal) rotation speed – 35 ATM…
Could anything shifted in the Air Distributor alignment only to return to normal a few minutes later?
I told you this Mystery Challenge will be hard to crack! J
Any ideas? Anyone?
Sam
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of cjpilot710(at)aol.com
Sent: Monday, June 03, 2013 8:51 PM
To: yak-list(at)matronics.com
Subject: Re: Engine Start Mystery
I agree with Bill if you had a valve stuck open, the engine would not kick passed that cylinder. I had this happen on the HS6a with a burnt exhaust valve. As for the super rotation - - - I am totally stumped. Pappy
In a message dated 6/3/2013 12:26:32 P.M. Eastern Daylight Time, bwade154(at)yahoo.com (bwade154(at)yahoo.com) writes:
| Quote: |
Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com>
To: yak-list(at)matronics.com
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
|
01234567890123
[quote][b]
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cd001633(at)mindspring.co
Guest
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| Posted: Mon Jun 03, 2013 7:10 pm Post subject: Engine start mystery |
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Hi Frank,
Thank you for responding.
Interesting point – I believe you are referring to a “Dieseling Effect” where combustion can occur in a hot cylinder on compression stroke when fuel or fuel vapor is present. I am thinking that if this what occurred I would have heard or seen some evidence of it, like popping or at least light smoke from the exhaust. Also, the engine was at least 15 minutes if not more from shut down (at the Gas Pump), so although very warm, it was not as hot to facilitate Dieseling, I believe.
Sam
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Frank Stelwagon
Sent: Monday, June 03, 2013 10:00 PM
To: yak-list(at)matronics.com
Subject: RE: Engine start mystery
I wonder, since the M14 is usually started with the mags off until it fires if the engine was actually running on the shower of sparks in the hot cylinder environment. The initial cylinder pull through with the normal compression then the soft cylinder may have been the cylinder actually burning residual fuel.
That would be similar to the early days of emission controls when the engines tended to run on after shut down. This was due to the high heat and the carburetor allowing fuel into the engine. Remember the shower of sparks is retarded and with the hot engine it may have actually been running.
Would have been interesting if the mags had been turned on while it was spinning fast, probably would have started fine.
| Quote: | | http://www.matronics.com/Navigator?Yak-List |
01234567
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cd001633(at)mindspring.co
Guest
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| Posted: Mon Jun 03, 2013 7:21 pm Post subject: Engine Start Mystery |
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Thanks Doc – I appreciate the input.
I will definitely followup on checking all the spark plugs (Chinese) as I will on other basic engine tests such as Compression testing each cylinder, Valve Lash / Rockers, checking the Oil Filter and Screen even Cylinder base bolts (common problem in the Housai, not the M-14).
Still, I can’t explain how any of the good suggestions for the problem so far on the List, if true, disappeared on the third engine start attempt where engine started and ran normally throughout the entire Power/RPM range and subsequent shut downs and re-starts – all normal…
The Mystery continues…
Sam
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of Roger Kemp M.D.
Sent: Monday, June 03, 2013 10:47 PM
To: yak-list(at)matronics.com
Subject: Re: Engine Start Mystery
A freek alignment of the compression rings with the oil scavenge rings comes to mind. As possible air start valve leaking. Any oil spray around the bases of your air start valves? loose spark plugs will allow air leaking also. Not likely I know. Check the ceramic bases on your plugs also. You could have blown the cores on a few of the plugs to if they are RU or Chinese. A fully blown core will be a blow torch I know but not some that are cracked.
Just a few more thoughts on the the subject.
Doc`
Sent from my iPad
On Jun 3, 2013, at 7:50 PM, cjpilot710(at)aol.com (cjpilot710(at)aol.com) wrote:
| Quote: |
I agree with Bill if you had a valve stuck open, the engine would not kick passed that cylinder. I had this happen on the HS6a with a burnt exhaust valve. As for the super rotation - - - I am totally stumped. Pappy
In a message dated 6/3/2013 12:26:32 P.M. Eastern Daylight Time, bwade154(at)yahoo.com (bwade154(at)yahoo.com) writes:
| Quote: |
Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
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viperdoc(at)mindspring.co
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| Posted: Mon Jun 03, 2013 8:28 pm Post subject: Engine Start Mystery |
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Agreed Sam, it has me scratching my head too!
Doc
Sent from my iPad
On Jun 3, 2013, at 10:19 PM, "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)> wrote:
[quote] <![endif]--> <![endif]-->
Thanks Doc – I appreciate the input.
I will definitely followup on checking all the spark plugs (Chinese) as I will on other basic engine tests such as Compression testing each cylinder, Valve Lash / Rockers, checking the Oil Filter and Screen even Cylinder base bolts (common problem in the Housai, not the M-14).
Still, I can’t explain how any of the good suggestions for the problem so far on the List, if true, disappeared on the third engine start attempt where engine started and ran normally throughout the entire Power/RPM range and subsequent shut downs and re-starts – all normal…
The Mystery continues…
Sam
From: owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com) [mailto:owner-yak-list-server(at)matronics.com (owner-yak-list-server(at)matronics.com)] On Behalf Of Roger Kemp M.D.
Sent: Monday, June 03, 2013 10:47 PM
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Subject: Re: Engine Start Mystery
A freek alignment of the compression rings with the oil scavenge rings comes to mind. As possible air start valve leaking. Any oil spray around the bases of your air start valves? loose spark plugs will allow air leaking also. Not likely I know. Check the ceramic bases on your plugs also. You could have blown the cores on a few of the plugs to if they are RU or Chinese. A fully blown core will be a blow torch I know but not some that are cracked.
Just a few more thoughts on the the subject.
Doc`
Sent from my iPad
On Jun 3, 2013, at 7:50 PM, cjpilot710(at)aol.com (cjpilot710(at)aol.com) wrote:
| Quote: |
I agree with Bill if you had a valve stuck open, the engine would not kick passed that cylinder. I had this happen on the HS6a with a burnt exhaust valve. As for the super rotation - - - I am totally stumped. Pappy
In a message dated 6/3/2013 12:26:32 P.M. Eastern Daylight Time, bwade154(at)yahoo.com (bwade154(at)yahoo.com) writes:
| Quote: |
Sam if you had a valve stuck open on the cylinder or just not seated well your start would stop on that cylinder and the start air would escape through the open valve exhaust or intake as the air is injected into the cylinder on the power stroke. As for spinning fast and not starting I don't have a clue.
Bill Wade
From: Sam Sax <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
To: yak-list(at)matronics.com (yak-list(at)matronics.com)
Sent: Sunday, June 2, 2013 10:43 PM
Subject: Engine Start Mystery
--> Yak-List message posted by: "Sam Sax" <cd001633(at)mindspring.com (cd001633(at)mindspring.com)>
This is a "good" one... I fly my CJ6 with the M-14p engine over a decade and have never seen or heard of this happening. I'd appreciate any ideas shedding light on this mystery...
Earlier today upon returning from a routine acro practice flight, taxied to the fuel pump and performed a normal shutdown.
After fueling and as a practice before each start, I have my GIB rotate the prop by hand a few blades as I prime (a little when engine is hot). My GIB reported that the first two blades were tight with normal feel of compression but the next blade was very soft. I didn’t think much of it and asked him to hop in and I commenced with normal engine start procedure.
Upon pressing the Air-Start button, the blades rotated in an amazingly fast rate - much faster than normal start rotation speed - as if there was no compression in the cylinders... Moreover, there was no ignition whatsoever during this fast rotation. I released the start button, waited a minute and tried again - same high speed rotation and no ignition...
At this time I got very worried and thought that the rear segment of the crankshaft somehow sheared off (on shutdown??)! Spent about 10 minutes with my knowledgeable GIB trying to figure out what could have happened. At that point, I asked him to try rotating the prop by hand and see if ANY of the cylinders have compression. As he was turning the prop by hand, I could see his strain as he rotates blade by blade - he proceeded to report feeling normal compression resistance on all blades. At this point I wanted to attempt another start. GIB was back in the rear cockpit and I pressed the starter button - engine started on the second blade (as it normally does)! I have the JP Instrument 9 Cylinder unit where I can see CHT and EGT for all 9 cylinders - All showing normal!
Taxied back to hangar - Performed a Magneto check - Normal. Oil, Fuel pressures and temps - normal. I shut down again and re-started two additional times in an effort to duplicate the problem... Started perfectly normal each time.
So... what the hell happened there? I am thinking a stuck intake valve but one stuck valve will not make the prop spin that fast on starting... Two stuck valves? Three?? Can that happen? If one did stick, why wasn't there any ignition on the other cylinders? If the sticking valve was the intake valve on #7 cylinder (that gets most of the Priming flow), I can see no ignition condition but this is only a guess.
Some engine info:
M14-P standard (360HP)
Total time: 765 hours since new
Last compression check (4 months ago): 77 - 78 all cylinders
Engine oil: Philips 25W60 multi viscosity oil
Last Valve Lash adjustment: 80 hours ago
System Air Pressure at first re-start attempt: 42 ATM, at last (Fifth start) 28 ATM
Location, Hot Miami, FL
Anyone seen anything like this before? Ideas?
Thank you in advance for any input,
Sam Sax
Miami ties such as List Un/Subscrip-= Photoshare, and much mum/Navigator?Yak-List" target="_blank">http://www.matronics.com/Navigator?p; --> http://forums.matr -Matt Dralle, List=========
[/url]
===================================//www.matronics.com/Navigator?Yak-List |
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cjpilot710(at)aol.com
Guest
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| Posted: Tue Jun 04, 2013 5:53 am Post subject: Engine start mystery |
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I've had this happen - where the "shower of sparks" was actually running the engine while holding the start button. Pappy
Sent from my iPad from some where on The 3rd rock from the Sun.
On Jun 3, 2013, at 9:59 PM, "Frank Stelwagon" <pfstelwagon(at)earthlink.net (pfstelwagon(at)earthlink.net)> wrote:
[quote] I wonder, since the M14 is usually started with the mags off until it fires if the engine was actually running on the shower of sparks in the hot cylinder environment. The initial cylinder pull through with the normal compression then the soft cylinder may have been the cylinder actually burning residual fuel.
That would be similar to the early days of emission controls when the engines tended to run on after shut down. This was due to the high heat and the carburetor allowing fuel into the engine. Remember the shower of sparks is retarded and with the hot engine it may have actually been running.
Would have been interesting if the mags had been turned on while it was spinning fast, probably would have started fine.
[b]
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richard.goode(at)russiana
Guest
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| Posted: Tue Jun 04, 2013 7:30 am Post subject: Engine start mystery |
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When you start the engine, of course with magnetos off, it IS running on the shower of sparks, and would continue to do so if you were able to separate the shower of sparks from the air start system!
Richard Goode
Rhodds Farm
Lyonshall
Hereford
HR5 3LW
Tel:Â +44 (0) 1544 340120
Fax: +44 (0) 1544 340129
www.russianaeros.com
From: owner-yak-list-server(at)matronics.com [mailto:owner-yak-list-server(at)matronics.com] On Behalf Of James Goolsby
Sent: 04 June 2013 14:51
To: yak-list(at)matronics.com
Subject: Re: RE: Engine start mystery
I've had this happen - where the "shower of sparks" was actually running the engine while holding the start button. Pappy
Sent from my iPad from some where on The 3rd rock from the Sun.
On Jun 3, 2013, at 9:59 PM, "Frank Stelwagon" <pfstelwagon(at)earthlink.net (pfstelwagon(at)earthlink.net)> wrote:
| Quote: |
I wonder, since the M14 is usually started with the mags off until it fires if the engine was actually running on the shower of sparks in the hot cylinder environment. The initial cylinder pull through with the normal compression then the soft cylinder may have been the cylinder actually burning residual fuel.
That would be similar to the early days of emission controls when the engines tended to run on after shut down. This was due to the high heat and the carburetor allowing fuel into the engine. Remember the shower of sparks is retarded and with the hot engine it may have actually been running.
Would have been interesting if the mags had been turned on while it was spinning fast, probably would have started fine.
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mark.bitterlich(at)navy.m
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| Posted: Tue Jun 04, 2013 10:18 am Post subject: Engine start mystery |
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That actually makes sense.
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