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TimRVator(at)comcast.net
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 Posted: Fri Sep 12, 2014 4:59 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
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Case crack: During my RV-10 2014 Condition Inspection I found a small
crack in the crank case under the #2 cylinder on my RV-10's IO-540. I
had rebuilt the engine 500 hours earlier. I knew it was a high time case
(6500 hours) with overhauled but high time cylinders, so I had paid
extra attention to looking for cracks. Unfortunately, I found one
(confirmed by dye penetrant). So, of course, the engine had to come of
the airplane and be completely disassembled for crank case replacement.
Ruined cam: Upon splitting the case, I found significant pitting on
several of the tappet bodies. The cam shaft had to be replaced, as did
several tappet bodies. I got a lot of engine assembly assistance from a
well regarded local repair station (Tom Schweitz at Aero Engines in
Winchester, VA – he's a super guy to work with). Tom told me that the
cam & tappet damage was caused by rust forming on the cam shaft wear
surface. I fly the RV-10 about 120 hours per year, which was apparently
not adequate to prevent rust on the cam shaft wear surface. Following
Tom's recommendation, I now use a Tempest engine dehumidifier to try to
prevent a recurrence.
CHTs too high (defective electronic ignition): Aero Engines provided me
a very good price on a low time (1500 TTSN) narrow deck crank case.
Since I had the engine torn down anyway, I elected to replace my
existing cylinders (high time, but servicable) with new Lycoming
cylinders. So I was expecting higher than normal CHTs on my first
flights. I found, however, that CHTs remained high even after oil
consumption had stabilized (beyond 10 hours). CHTs would climb above 430
on take off unless I reduced power at about 1000'. CHTs were nearly 430
in low level full throttle flight with mixture full rich. Baffling
checks and all the other proven RV-10 cooling tips from Tim Olsen's
wonderful web site didn't seem to help much. Eventually I began to
suspect advanced timing (thanks, Mike Busch). I found that when I
switched off the Lightspeed electronic ignition all my CHTs in climb and
full power operation were normal. My mag timing was fine. Using an
automotive strobe timing light, I discovered that the Lightspeed
electronic ignition (EI) was stuck at 43 degrees BTDC (!!), and did not
change timing based on manifold pressure. This is a very risky situation
– advanced timing reduces detonation margin. A borescope inspection
revealed no signs of detonation damage. A recent Mike Busch webinar
describes a brand new engine being destroyed by advanced timing, so I
feel I dodged a bullet.
I paid Lightspeed to repair the defective EI computer (bad connection on
a timing capacitor, according to Klaus) and to update the hardware to
the latest revision. After reinstalling the EI computer, all CHTs are
now normal.
Power stumble (air leak): At this point, I was hyper attuned to any
engine performance abnormality. I noticed an occasional slight power
reduction for a second or two at a time, when operating at lower power
settings. Based on discussion with a Lycoming tech rep during OSH, I
went on a hunt for any air leaking into the fuel lines. The Lycoming rep
suggested the fuel flow transducer (red cube) as a frequent source of
trouble (including cavitation bubbles). I torqued all fuel fittings
firewall forward. Inside the cabin, I removed the red cube, and
discovered evidence of a fuel seep at the fitting on the forward side of
the cube. After considerable fiddling, I was able to achieve another
turn on the fuel fitting without exceeding the red cube's torque spec.
After reinstalling the red cube, the occasional power stumble in flight
has not recurred.
Several airplane experts have been very helpful to me in this process.
Dick Koehler (IA, tech counselor, EAA “Hints for Homebuilders” webinar
presenter) was an invaluable source of advice. Tom Schweitz at
Winchester Aero Engines was fabulous to work with. He saved me a bunch
of money on parts, and provided invaluable help getting the project
finished.
--
Tim Lewis -- HEF (Manassas, VA)
A&P
RV-6A N47TD -- 1104 hrs - sold
RV-10 N31TD -- 500 hrs
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Tim Olson
Joined: 25 Jan 2007
Posts: 2879
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| Posted: Fri Sep 12, 2014 6:01 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
|
|
Wow Tim, you really had the adventure lately! Thanks for posting.
Great tips for things people can look for.
I'm hoping I don't get rust on my cams, considering I'm not down
to about 100 hours per year or maybe even less. What oil are you
using, and are you using camguard? I'm still using exxon elite
for now, but bought 4 cases of Phillips X/C at OSH. Camguard from
everything I've read, is actually a worthwhile rust preventative,
so I'm going to stick with using it. Lots of good info from Aviation
consumer on it. Also, i think I just read within the last week or
two that Continental is going to be testing camguard. It sounds like
they find it intriguing as well. Maybe they'll make it one of their
recommendations officially some day.
Anyway, just some questions for you.
Tim
On 9/12/2014 7:59 PM, Tim Lewis wrote:
| Quote: |
Case crack: During my RV-10 2014 Condition Inspection I found a small
crack in the crank case under the #2 cylinder on my RV-10's IO-540. I
had rebuilt the engine 500 hours earlier. I knew it was a high time case
(6500 hours) with overhauled but high time cylinders, so I had paid
extra attention to looking for cracks. Unfortunately, I found one
(confirmed by dye penetrant). So, of course, the engine had to come of
the airplane and be completely disassembled for crank case replacement.
Ruined cam: Upon splitting the case, I found significant pitting on
several of the tappet bodies. The cam shaft had to be replaced, as did
several tappet bodies. I got a lot of engine assembly assistance from a
well regarded local repair station (Tom Schweitz at Aero Engines in
Winchester, VA – he's a super guy to work with). Tom told me that the
cam & tappet damage was caused by rust forming on the cam shaft wear
surface. I fly the RV-10 about 120 hours per year, which was apparently
not adequate to prevent rust on the cam shaft wear surface. Following
Tom's recommendation, I now use a Tempest engine dehumidifier to try to
prevent a recurrence.
CHTs too high (defective electronic ignition): Aero Engines provided me
a very good price on a low time (1500 TTSN) narrow deck crank case.
Since I had the engine torn down anyway, I elected to replace my
existing cylinders (high time, but servicable) with new Lycoming
cylinders. So I was expecting higher than normal CHTs on my first
flights. I found, however, that CHTs remained high even after oil
consumption had stabilized (beyond 10 hours). CHTs would climb above 430
on take off unless I reduced power at about 1000'. CHTs were nearly 430
in low level full throttle flight with mixture full rich. Baffling
checks and all the other proven RV-10 cooling tips from Tim Olsen's
wonderful web site didn't seem to help much. Eventually I began to
suspect advanced timing (thanks, Mike Busch). I found that when I
switched off the Lightspeed electronic ignition all my CHTs in climb and
full power operation were normal. My mag timing was fine. Using an
automotive strobe timing light, I discovered that the Lightspeed
electronic ignition (EI) was stuck at 43 degrees BTDC (!!), and did not
change timing based on manifold pressure. This is a very risky situation
– advanced timing reduces detonation margin. A borescope inspection
revealed no signs of detonation damage. A recent Mike Busch webinar
describes a brand new engine being destroyed by advanced timing, so I
feel I dodged a bullet.
I paid Lightspeed to repair the defective EI computer (bad connection on
a timing capacitor, according to Klaus) and to update the hardware to
the latest revision. After reinstalling the EI computer, all CHTs are
now normal.
Power stumble (air leak): At this point, I was hyper attuned to any
engine performance abnormality. I noticed an occasional slight power
reduction for a second or two at a time, when operating at lower power
settings. Based on discussion with a Lycoming tech rep during OSH, I
went on a hunt for any air leaking into the fuel lines. The Lycoming rep
suggested the fuel flow transducer (red cube) as a frequent source of
trouble (including cavitation bubbles). I torqued all fuel fittings
firewall forward. Inside the cabin, I removed the red cube, and
discovered evidence of a fuel seep at the fitting on the forward side of
the cube. After considerable fiddling, I was able to achieve another
turn on the fuel fitting without exceeding the red cube's torque spec.
After reinstalling the red cube, the occasional power stumble in flight
has not recurred.
Several airplane experts have been very helpful to me in this process.
Dick Koehler (IA, tech counselor, EAA “Hints for Homebuilders” webinar
presenter) was an invaluable source of advice. Tom Schweitz at
Winchester Aero Engines was fabulous to work with. He saved me a bunch
of money on parts, and provided invaluable help getting the project
finished.
|
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http://www.matronics.com/Navigator?RV10-List |
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jmjones2000(at)mindspring
Guest
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| Posted: Fri Sep 12, 2014 6:17 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
|
|
Plus one more for ASL Camguard!
Justin
On Sep 12, 2014, at 18:00, Tim Olson <Tim(at)MyRV10.com> wrote:
| Quote: |
Wow Tim, you really had the adventure lately! Thanks for posting.
Great tips for things people can look for.
I'm hoping I don't get rust on my cams, considering I'm not down
to about 100 hours per year or maybe even less. What oil are you
using, and are you using camguard? I'm still using exxon elite
for now, but bought 4 cases of Phillips X/C at OSH. Camguard from
everything I've read, is actually a worthwhile rust preventative,
so I'm going to stick with using it. Lots of good info from Aviation
consumer on it. Also, i think I just read within the last week or
two that Continental is going to be testing camguard. It sounds like
they find it intriguing as well. Maybe they'll make it one of their
recommendations officially some day.
Anyway, just some questions for you.
Tim
On 9/12/2014 7:59 PM, Tim Lewis wrote:
>
>
> Case crack: During my RV-10 2014 Condition Inspection I found a small
> crack in the crank case under the #2 cylinder on my RV-10's IO-540. I
> had rebuilt the engine 500 hours earlier. I knew it was a high time case
> (6500 hours) with overhauled but high time cylinders, so I had paid
> extra attention to looking for cracks. Unfortunately, I found one
> (confirmed by dye penetrant). So, of course, the engine had to come of
> the airplane and be completely disassembled for crank case replacement.
>
> Ruined cam: Upon splitting the case, I found significant pitting on
> several of the tappet bodies. The cam shaft had to be replaced, as did
> several tappet bodies. I got a lot of engine assembly assistance from a
> well regarded local repair station (Tom Schweitz at Aero Engines in
> Winchester, VA – he's a super guy to work with). Tom told me that the
> cam & tappet damage was caused by rust forming on the cam shaft wear
> surface. I fly the RV-10 about 120 hours per year, which was apparently
> not adequate to prevent rust on the cam shaft wear surface. Following
> Tom's recommendation, I now use a Tempest engine dehumidifier to try to
> prevent a recurrence.
>
> CHTs too high (defective electronic ignition): Aero Engines provided me
> a very good price on a low time (1500 TTSN) narrow deck crank case.
> Since I had the engine torn down anyway, I elected to replace my
> existing cylinders (high time, but servicable) with new Lycoming
> cylinders. So I was expecting higher than normal CHTs on my first
> flights. I found, however, that CHTs remained high even after oil
> consumption had stabilized (beyond 10 hours). CHTs would climb above 430
> on take off unless I reduced power at about 1000'. CHTs were nearly 430
> in low level full throttle flight with mixture full rich. Baffling
> checks and all the other proven RV-10 cooling tips from Tim Olsen's
> wonderful web site didn't seem to help much. Eventually I began to
> suspect advanced timing (thanks, Mike Busch). I found that when I
> switched off the Lightspeed electronic ignition all my CHTs in climb and
> full power operation were normal. My mag timing was fine. Using an
> automotive strobe timing light, I discovered that the Lightspeed
> electronic ignition (EI) was stuck at 43 degrees BTDC (!!), and did not
> change timing based on manifold pressure. This is a very risky situation
> – advanced timing reduces detonation margin. A borescope inspection
> revealed no signs of detonation damage. A recent Mike Busch webinar
> describes a brand new engine being destroyed by advanced timing, so I
> feel I dodged a bullet.
>
> I paid Lightspeed to repair the defective EI computer (bad connection on
> a timing capacitor, according to Klaus) and to update the hardware to
> the latest revision. After reinstalling the EI computer, all CHTs are
> now normal.
>
> Power stumble (air leak): At this point, I was hyper attuned to any
> engine performance abnormality. I noticed an occasional slight power
> reduction for a second or two at a time, when operating at lower power
> settings. Based on discussion with a Lycoming tech rep during OSH, I
> went on a hunt for any air leaking into the fuel lines. The Lycoming rep
> suggested the fuel flow transducer (red cube) as a frequent source of
> trouble (including cavitation bubbles). I torqued all fuel fittings
> firewall forward. Inside the cabin, I removed the red cube, and
> discovered evidence of a fuel seep at the fitting on the forward side of
> the cube. After considerable fiddling, I was able to achieve another
> turn on the fuel fitting without exceeding the red cube's torque spec.
> After reinstalling the red cube, the occasional power stumble in flight
> has not recurred.
>
> Several airplane experts have been very helpful to me in this process.
> Dick Koehler (IA, tech counselor, EAA “Hints for Homebuilders” webinar
> presenter) was an invaluable source of advice. Tom Schweitz at
> Winchester Aero Engines was fabulous to work with. He saved me a bunch
> of money on parts, and provided invaluable help getting the project
> finished.
|
| | - The Matronics RV10-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?RV10-List |
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TimRVator(at)comcast.net
Guest
|
| Posted: Fri Sep 12, 2014 6:38 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
|
|
I used Phillips XC 20W50 and Camguard for the whole 500 hours, except
for break in. Oil analysis (every 50 hours) revealed nothing
concerning. Oil filter inspection sometimes revealed a few very small
amounts of tiny ferrous "hairs." Based on that data, I was quite
surprised when we split my case and I saw the cratered face of a couple
of my tappets.
According to Tom at Aero Engines (a well regarded shop in this area),
they almost never see this with flight school airplanes (which fly
daily), but it is not uncommon with owner-flown aircraft. Tom showed me
a pitted set from a recent Continental overhaul, to demonstrate that
Lycomings aren't the only ones that have this happen.
--
Tim Lewis -- HEF (Manassas, VA)
A&P
RV-6A N47TD -- 1104 hrs - sold
RV-10 N31TD -- 500 hrs
Tim Olson said the following on 9/12/2014 10:00 PM:
| Quote: |
Wow Tim, you really had the adventure lately! Thanks for posting.
Great tips for things people can look for.
I'm hoping I don't get rust on my cams, considering I'm not down
to about 100 hours per year or maybe even less. What oil are you
using, and are you using camguard? I'm still using exxon elite
for now, but bought 4 cases of Phillips X/C at OSH. Camguard from
everything I've read, is actually a worthwhile rust preventative,
so I'm going to stick with using it. Lots of good info from Aviation
consumer on it. Also, i think I just read within the last week or
two that Continental is going to be testing camguard. It sounds like
they find it intriguing as well. Maybe they'll make it one of their
recommendations officially some day.
Anyway, just some questions for you.
Tim
On 9/12/2014 7:59 PM, Tim Lewis wrote:
>
>
> Case crack: During my RV-10 2014 Condition Inspection I found a small
> crack in the crank case under the #2 cylinder on my RV-10's IO-540. I
> had rebuilt the engine 500 hours earlier. I knew it was a high time case
> (6500 hours) with overhauled but high time cylinders, so I had paid
> extra attention to looking for cracks. Unfortunately, I found one
> (confirmed by dye penetrant). So, of course, the engine had to come of
> the airplane and be completely disassembled for crank case replacement.
>
> Ruined cam: Upon splitting the case, I found significant pitting on
> several of the tappet bodies. The cam shaft had to be replaced, as did
> several tappet bodies. I got a lot of engine assembly assistance from a
> well regarded local repair station (Tom Schweitz at Aero Engines in
> Winchester, VA – he's a super guy to work with). Tom told me that the
> cam & tappet damage was caused by rust forming on the cam shaft wear
> surface. I fly the RV-10 about 120 hours per year, which was apparently
> not adequate to prevent rust on the cam shaft wear surface. Following
> Tom's recommendation, I now use a Tempest engine dehumidifier to try to
> prevent a recurrence.
>
> CHTs too high (defective electronic ignition): Aero Engines provided me
> a very good price on a low time (1500 TTSN) narrow deck crank case.
> Since I had the engine torn down anyway, I elected to replace my
> existing cylinders (high time, but servicable) with new Lycoming
> cylinders. So I was expecting higher than normal CHTs on my first
> flights. I found, however, that CHTs remained high even after oil
> consumption had stabilized (beyond 10 hours). CHTs would climb above 430
> on take off unless I reduced power at about 1000'. CHTs were nearly 430
> in low level full throttle flight with mixture full rich. Baffling
> checks and all the other proven RV-10 cooling tips from Tim Olsen's
> wonderful web site didn't seem to help much. Eventually I began to
> suspect advanced timing (thanks, Mike Busch). I found that when I
> switched off the Lightspeed electronic ignition all my CHTs in climb and
> full power operation were normal. My mag timing was fine. Using an
> automotive strobe timing light, I discovered that the Lightspeed
> electronic ignition (EI) was stuck at 43 degrees BTDC (!!), and did not
> change timing based on manifold pressure. This is a very risky situation
> – advanced timing reduces detonation margin. A borescope inspection
> revealed no signs of detonation damage. A recent Mike Busch webinar
> describes a brand new engine being destroyed by advanced timing, so I
> feel I dodged a bullet.
>
> I paid Lightspeed to repair the defective EI computer (bad connection on
> a timing capacitor, according to Klaus) and to update the hardware to
> the latest revision. After reinstalling the EI computer, all CHTs are
> now normal.
>
> Power stumble (air leak): At this point, I was hyper attuned to any
> engine performance abnormality. I noticed an occasional slight power
> reduction for a second or two at a time, when operating at lower power
> settings. Based on discussion with a Lycoming tech rep during OSH, I
> went on a hunt for any air leaking into the fuel lines. The Lycoming rep
> suggested the fuel flow transducer (red cube) as a frequent source of
> trouble (including cavitation bubbles). I torqued all fuel fittings
> firewall forward. Inside the cabin, I removed the red cube, and
> discovered evidence of a fuel seep at the fitting on the forward side of
> the cube. After considerable fiddling, I was able to achieve another
> turn on the fuel fitting without exceeding the red cube's torque spec.
> After reinstalling the red cube, the occasional power stumble in flight
> has not recurred.
>
> Several airplane experts have been very helpful to me in this process.
> Dick Koehler (IA, tech counselor, EAA “Hints for Homebuilders” webinar
> presenter) was an invaluable source of advice. Tom Schweitz at
> Winchester Aero Engines was fabulous to work with. He saved me a bunch
> of money on parts, and provided invaluable help getting the project
> finished.
>
|
| | - The Matronics RV10-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?RV10-List |
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jmjones2000(at)mindspring
Guest
|
| Posted: Fri Sep 12, 2014 6:47 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
|
|
Maybe it's time for a heated hangar. Engine overhauls get expensive!!
On Sep 12, 2014, at 18:37, Tim Lewis <TimRVator(at)comcast.net> wrote:
| Quote: |
I used Phillips XC 20W50 and Camguard for the whole 500 hours, except for break in. Oil analysis (every 50 hours) revealed nothing concerning. Oil filter inspection sometimes revealed a few very small amounts of tiny ferrous "hairs." Based on that data, I was quite surprised when we split my case and I saw the cratered face of a couple of my tappets.
According to Tom at Aero Engines (a well regarded shop in this area), they almost never see this with flight school airplanes (which fly daily), but it is not uncommon with owner-flown aircraft. Tom showed me a pitted set from a recent Continental overhaul, to demonstrate that Lycomings aren't the only ones that have this happen.
--
Tim Lewis -- HEF (Manassas, VA)
A&P
RV-6A N47TD -- 1104 hrs - sold
RV-10 N31TD -- 500 hrs
Tim Olson said the following on 9/12/2014 10:00 PM:
>
>
> Wow Tim, you really had the adventure lately! Thanks for posting.
> Great tips for things people can look for.
> I'm hoping I don't get rust on my cams, considering I'm not down
> to about 100 hours per year or maybe even less. What oil are you
> using, and are you using camguard? I'm still using exxon elite
> for now, but bought 4 cases of Phillips X/C at OSH. Camguard from
> everything I've read, is actually a worthwhile rust preventative,
> so I'm going to stick with using it. Lots of good info from Aviation
> consumer on it. Also, i think I just read within the last week or
> two that Continental is going to be testing camguard. It sounds like
> they find it intriguing as well. Maybe they'll make it one of their
> recommendations officially some day.
>
> Anyway, just some questions for you.
> Tim
>
>
> On 9/12/2014 7:59 PM, Tim Lewis wrote:
>>
>>
>> Case crack: During my RV-10 2014 Condition Inspection I found a small
>> crack in the crank case under the #2 cylinder on my RV-10's IO-540. I
>> had rebuilt the engine 500 hours earlier. I knew it was a high time case
>> (6500 hours) with overhauled but high time cylinders, so I had paid
>> extra attention to looking for cracks. Unfortunately, I found one
>> (confirmed by dye penetrant). So, of course, the engine had to come of
>> the airplane and be completely disassembled for crank case replacement.
>>
>> Ruined cam: Upon splitting the case, I found significant pitting on
>> several of the tappet bodies. The cam shaft had to be replaced, as did
>> several tappet bodies. I got a lot of engine assembly assistance from a
>> well regarded local repair station (Tom Schweitz at Aero Engines in
>> Winchester, VA – he's a super guy to work with). Tom told me that the
>> cam & tappet damage was caused by rust forming on the cam shaft wear
>> surface. I fly the RV-10 about 120 hours per year, which was apparently
>> not adequate to prevent rust on the cam shaft wear surface. Following
>> Tom's recommendation, I now use a Tempest engine dehumidifier to try to
>> prevent a recurrence.
>>
>> CHTs too high (defective electronic ignition): Aero Engines provided me
>> a very good price on a low time (1500 TTSN) narrow deck crank case.
>> Since I had the engine torn down anyway, I elected to replace my
>> existing cylinders (high time, but servicable) with new Lycoming
>> cylinders. So I was expecting higher than normal CHTs on my first
>> flights. I found, however, that CHTs remained high even after oil
>> consumption had stabilized (beyond 10 hours). CHTs would climb above 430
>> on take off unless I reduced power at about 1000'. CHTs were nearly 430
>> in low level full throttle flight with mixture full rich. Baffling
>> checks and all the other proven RV-10 cooling tips from Tim Olsen's
>> wonderful web site didn't seem to help much. Eventually I began to
>> suspect advanced timing (thanks, Mike Busch). I found that when I
>> switched off the Lightspeed electronic ignition all my CHTs in climb and
>> full power operation were normal. My mag timing was fine. Using an
>> automotive strobe timing light, I discovered that the Lightspeed
>> electronic ignition (EI) was stuck at 43 degrees BTDC (!!), and did not
>> change timing based on manifold pressure. This is a very risky situation
>> – advanced timing reduces detonation margin. A borescope inspection
>> revealed no signs of detonation damage. A recent Mike Busch webinar
>> describes a brand new engine being destroyed by advanced timing, so I
>> feel I dodged a bullet.
>>
>> I paid Lightspeed to repair the defective EI computer (bad connection on
>> a timing capacitor, according to Klaus) and to update the hardware to
>> the latest revision. After reinstalling the EI computer, all CHTs are
>> now normal.
>>
>> Power stumble (air leak): At this point, I was hyper attuned to any
>> engine performance abnormality. I noticed an occasional slight power
>> reduction for a second or two at a time, when operating at lower power
>> settings. Based on discussion with a Lycoming tech rep during OSH, I
>> went on a hunt for any air leaking into the fuel lines. The Lycoming rep
>> suggested the fuel flow transducer (red cube) as a frequent source of
>> trouble (including cavitation bubbles). I torqued all fuel fittings
>> firewall forward. Inside the cabin, I removed the red cube, and
>> discovered evidence of a fuel seep at the fitting on the forward side of
>> the cube. After considerable fiddling, I was able to achieve another
>> turn on the fuel fitting without exceeding the red cube's torque spec.
>> After reinstalling the red cube, the occasional power stumble in flight
>> has not recurred.
>>
>> Several airplane experts have been very helpful to me in this process.
>> Dick Koehler (IA, tech counselor, EAA “Hints for Homebuilders” webinar
>> presenter) was an invaluable source of advice. Tom Schweitz at
>> Winchester Aero Engines was fabulous to work with. He saved me a bunch
>> of money on parts, and provided invaluable help getting the project
>> finished.
|
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Mike Whisky
Joined: 05 Jun 2006
Posts: 336
Location: Switzerland
|
| Posted: Sat Sep 13, 2014 8:34 am Post subject: Re: Engine marathon: Case crack, bad cam, high CHT, stumbli |
|
|
Does any engineer or metallurgist now why parts like cam shafts are not made of an none corrosive steel alloy? Just reviewing to understand why not the root cause has been tackled in the past by the engine manufacturers. I guess that problems like this won't appear in automotive engines.
Just my 20cc
Mike
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RV-10 builder (flying)
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glastar(at)gmx.net
Guest
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| Posted: Sat Sep 13, 2014 12:00 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
|
|
On 13.09.2014 02:59, Tim Lewis wrote:
| Quote: | Ruined cam: Upon splitting the case, I found significant pitting on
several of the tappet bodies. The cam shaft had to be replaced, as did
several tappet bodies. I got a lot of engine assembly assistance from
a well regarded local repair station (Tom Schweitz at Aero Engines in
Winchester, VA – he's a super guy to work with). Tom told me that the
cam & tappet damage was caused by rust forming on the cam shaft wear
surface. I fly the RV-10 about 120 hours per year, which was
apparently not adequate to prevent rust on the cam shaft wear surface.
Following Tom's recommendation, I now use a Tempest engine
dehumidifier to try to prevent a recurrence.
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Tim, I know how painful this is, I had an O-320 with exactly that issue,
I can tell you, if you see in the filter this fine shiny metal flakes be
aware to expect cam shaft troubles. I had as well oil analysis done all
the time, it showed a bit higher metal values but nowhere in an area
regarded as dangerous. I was as well far away from the Coming SL
describing how much metal you can have. At the end Lycoming steered me
to their SB 480
http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20480E%20%2804-13-2005%29/Oil%20and%20Filter%20Change%20and%20Screen%20Cleaning;%20Oil%20Filter-Screen%20Content%20Inspection.pdf
which more or less tells you latest all 4 month you have to change oil
and filter ....
Cheers Werner
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jmjones2000(at)mindspring
Guest
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| Posted: Sat Sep 13, 2014 12:58 pm Post subject: Engine marathon: Case crack, bad cam, high CHT, stumbling |
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Has anyone considered the Ney Nozzels? I have heard of one guy that had oil pressure issues after he had them put in, but I'm not sure if it was ever attributed to the nozzles or another defective part. If memory serves me correctly, he may have found a missing oil galley plug on a subsequent shut down.
The nozzles will help while the engine is running, but most if the corrosion comes from the aircraft sitting out in the elements. Condensation builds on the camshaft after a warm engine is shut down. This is where ASL Camguard claims to help. It is not suppose to shear off of the camshaft after shutdown, leaving a coat of oil covering the cam and stopping corrosion.
The other thing that will wear a camshaft down quickly is allowing the lycoming to idle below 1,000 rpm. I am not advocating to set the idle higher than the manufacturer recommends, but our lycoming engines rely on splash oil to lubricate the camshaft. There is simply not enough splash oil below 1000 rpm to sufficiently lubricate the cam. I try to limit my time below 1000 rpm.
The dehydrating plugs couldn't hurt to slide in after shutdown.
Hope this helps
Justin
On Sep 13, 2014, at 11:48, Werner Schneider <glastar(at)gmx.net> wrote:
| Quote: |
On 13.09.2014 02:59, Tim Lewis wrote:
>
> Ruined cam: Upon splitting the case, I found significant pitting on several of the tappet bodies. The cam shaft had to be replaced, as did several tappet bodies. I got a lot of engine assembly assistance from a well regarded local repair station (Tom Schweitz at Aero Engines in Winchester, VA – he's a super guy to work with). Tom told me that the cam & tappet damage was caused by rust forming on the cam shaft wear surface. I fly the RV-10 about 120 hours per year, which was apparently not adequate to prevent rust on the cam shaft wear surface. Following Tom's recommendation, I now use a Tempest engine dehumidifier to try to prevent a recurrence.
Tim, I know how painful this is, I had an O-320 with exactly that issue, I can tell you, if you see in the filter this fine shiny metal flakes be aware to expect cam shaft troubles. I had as well oil analysis done all the time, it showed a bit higher metal values but nowhere in an area regarded as dangerous. I was as well far away from the Coming SL describing how much metal you can have. At the end Lycoming steered me to their SB 480
http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20480E%20%2804-13-2005%29/Oil%20and%20Filter%20Change%20and%20Screen%20Cleaning;%20Oil%20Filter-Screen%20Content%20Inspection.pdf
which more or less tells you latest all 4 month you have to change oil and filter ....
Cheers Werner
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