KR> Engine compression loss

[Joseph H. Horton]

Good theory, but I don't think I can subscribe as I fouled one cylinder
on the way to the gathering a few weeks ago and yes I knew that something
was not right from roughness, as far as a major power loss that just did
not happen. I don't believe I lost more that a few hundred rpm and
certainly could have sustained flight if I would not have been landing at
the time anyway. One push of the button on the EIS confirmed that the #2
cylinder was completely cold. Exhaust temp was about 400 and head temp
was rapidly dropping well below 200.  I was not worried in that it was
producing plenty of power even for a go around if needed but I didn't
like it either. In my case i had reduced throttle and caused a rich
condition that actually seemed to flood the # 2 cylinder that I caused by
miss using the mixture in the much colder weather conditions after
summer. I was able to reproduce this condition in cruise and quickly
learned how to manage it. After getting back home I readjusted the Aero
carb for winter mixture and the problem is gone. 
No help for Mark here just an example how many different things
could happen.
Joe Horton, Coopersburg, PA.
joe.kr2s.buil...@juno.com

On Mon, 23 Oct 2006 15:08:55 -0400 "Colin Rainey"
 writes:
> Mark and netters
> Losing the #5 intake valve would cause the air fuel mix that entered 
> the
> cylinder to be expelled back into the intake head area, causing the 
> next
> intake of either #1 or #3 to be very complete as it would 
> temporarily act
> similar to a form of boost, making pressure in the intake. At lower 
> rpms it
> might possible cause the next cylinder to have a lower charge due to 
> the
> reversion of the flow, but the third in the series would be 
> unaffected. At
> higher rpms, this would be negligeable. Since #5 was making no 
> compression,
> the engine would have to lug the mass of piston around as well as 
> making
> power to run, so it would affect power by more the 1/5, more like 30 
> to 40%.
> You would also feel a very pronounced missing due to the dramatic 
> difference
> between a cylinder that makes decent power and then the dead one.
> 
> My opinion about the progression of your problem is that you began 
> to run
> rich due to the carb issues, the associated carbon buildups resulted 
> in hot
> spots in the cylinders, which lead to pre-ignition and detonation, 
> which
> damaged the head area immediately around the intake valve.  The 
> carbon
> buildup would act like little matches lighting off the fuel early,
> especially when you ran the auto pump gas.
> 
> JMHO...
> 
> Colin Rainey
> Independent Loan Officer
> Branch 2375
> Apex Mortgage Company
> 386.615.3388 Home Office
> 407.739.0834 Cell
> 407.557.3260 Fax
> brokerpi...@bellsouth.net
> 
> ___
> Search the KRnet Archives at 
> http://www.maddyhome.com/krsrch/index.jsp
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> please see other KRnet info at http://www.krnet.org/info.html
> 
> 


Joe Horton, Coopersburg, PA.
joe.kr2s.buil...@juno.com

KR> Engine compression loss

[Brian Kraut]

With the intake valve open when the plug fires would it ignite the fuel in
the cylinder and intake?  I would imagine that would cause the other two
cylinders to draw in a bunch of exhaust and cause all kinds of power loss.
Might even travel back through the intake and cause problems on the other
side of the engine.

Mark, is there any soot or other evidence in the intake manifold indicating
fuel burning in there?

Who did the heads on your engine?  Were the seats replaced, just ground and
lapped?

Brian Kraut
Engineering Alternatives, Inc.
www.engalt.com

-Original Message-
From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On
Behalf Of Colin Rainey
Sent: Monday, October 23, 2006 3:09 PM
To: KRnet
Subject: KR> Engine compression loss


Mark and netters
Losing the #5 intake valve would cause the air fuel mix that entered the
cylinder to be expelled back into the intake head area, causing the next
intake of either #1 or #3 to be very complete as it would temporarily act
similar to a form of boost, making pressure in the intake. At lower rpms it
might possible cause the next cylinder to have a lower charge due to the
reversion of the flow, but the third in the series would be unaffected. At
higher rpms, this would be negligeable. Since #5 was making no compression,
the engine would have to lug the mass of piston around as well as making
power to run, so it would affect power by more the 1/5, more like 30 to 40%.
You would also feel a very pronounced missing due to the dramatic difference
between a cylinder that makes decent power and then the dead one.

My opinion about the progression of your problem is that you began to run
rich due to the carb issues, the associated carbon buildups resulted in hot
spots in the cylinders, which lead to pre-ignition and detonation, which
damaged the head area immediately around the intake valve.  The carbon
buildup would act like little matches lighting off the fuel early,
especially when you ran the auto pump gas.

JMHO...

Colin Rainey
Independent Loan Officer
Branch 2375
Apex Mortgage Company
386.615.3388 Home Office
407.739.0834 Cell
407.557.3260 Fax
brokerpi...@bellsouth.net

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KR> Engine compression loss

[Mark Jones]

Brian,
I just took a close look at the head. There is no soot in the intake log 
that I can noticeably detect. My heads were done by a very close friend who 
is a perfectionist when it comes to detail and is also a builder of 
experimental aircraft and engines. The seats in the head are original 
factory (as far as I know) as they were not replaced when the heads were 
rebuilt. They were ground and lapped. If you remember, last year, I had to 
replace the  # 5 and  # 6 pistons and rings due to overheating because of a 
cooling issue . http://www.flykr2s.com/enginebaffles.html The number 5 was 
damaged the most. It is suspected that this damage loosened up the seat 
which caused it to slowly work it's way out. The reason I say slowly is 
because back at the first of this summer, I began to notice engine roughness 
which kept getting worse at the summer went on. All the time I was looking 
at carb and airbox issues. I had done a compression test shortly before the 
roughness began so I never thought that compression would be an issue. After 
I repaired the carb and still had a rough running engine, that is when I did 
another compression test last weekend.

Mark Jones (N886MJ)
Wales, WI
Visit my web site: www.flykr2s.com
E-mail: flyk...@wi.rr.com
- Original Message - 
From: "Brian Kraut" <brian.kr...@engalt.com>
To: "KRnet" <kr...@mylist.net>
Sent: Monday, October 23, 2006 6:58 PM
Subject: RE: KR> Engine compression loss


> With the intake valve open when the plug fires would it ignite the fuel in
> the cylinder and intake?  I would imagine that would cause the other two
> cylinders to draw in a bunch of exhaust and cause all kinds of power loss.
> Might even travel back through the intake and cause problems on the other
> side of the engine.
>
> Mark, is there any soot or other evidence in the intake manifold 
> indicating
> fuel burning in there?
>
> Who did the heads on your engine?  Were the seats replaced, just ground 
> and
> lapped?
>
> Brian Kraut
> Engineering Alternatives, Inc.
> www.engalt.com
>
> -Original Message-
> From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On
> Behalf Of Colin Rainey
> Sent: Monday, October 23, 2006 3:09 PM
> To: KRnet
> Subject: KR> Engine compression loss
>
>
> Mark and netters
> Losing the #5 intake valve would cause the air fuel mix that entered the
> cylinder to be expelled back into the intake head area, causing the next
> intake of either #1 or #3 to be very complete as it would temporarily act
> similar to a form of boost, making pressure in the intake. At lower rpms 
> it
> might possible cause the next cylinder to have a lower charge due to the
> reversion of the flow, but the third in the series would be unaffected. At
> higher rpms, this would be negligeable. Since #5 was making no 
> compression,
> the engine would have to lug the mass of piston around as well as making
> power to run, so it would affect power by more the 1/5, more like 30 to 
> 40%.
> You would also feel a very pronounced missing due to the dramatic 
> difference
> between a cylinder that makes decent power and then the dead one.
>
> My opinion about the progression of your problem is that you began to run
> rich due to the carb issues, the associated carbon buildups resulted in 
> hot
> spots in the cylinders, which lead to pre-ignition and detonation, which
> damaged the head area immediately around the intake valve.  The carbon
> buildup would act like little matches lighting off the fuel early,
> especially when you ran the auto pump gas.
>
> JMHO...
>
> Colin Rainey
> Independent Loan Officer
> Branch 2375
> Apex Mortgage Company
> 386.615.3388 Home Office
> 407.739.0834 Cell
> 407.557.3260 Fax
> brokerpi...@bellsouth.net
>
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html
>
>
>
> ___
> Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp
> to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net
> please see other KRnet info at http://www.krnet.org/info.html