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  #1  
Old 01-22-2013, 09:00 PM
mtnflyer mtnflyer is offline
 
Join Date: Jul 2007
Location: granby co
Posts: 135
Default A little help from my friends? Lycoming camshaft

Can a person inspect a cam on a lycoming without splitting the case or pulling a cylinder????? Thanks
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  #2  
Old 01-22-2013, 09:33 PM
tim2542 tim2542 is offline
 
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Location: Redding,Ca
Posts: 235
Default Sorry

No practicle way to do it, but its not hard to pull a jug.
Don't forget the followers are likely to fail before the cam
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  #3  
Old 01-22-2013, 10:32 PM
jrs14855 jrs14855 is offline
 
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Location: Gallup, NM
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Default Cam

IIRC on the four cylinder Lycoming two cylinders share a pair of cam lobes.
This would be the most critical area as these lobes are doing twice the work as the others.
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  #4  
Old 01-22-2013, 10:48 PM
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Snowflake Snowflake is offline
 
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Default

I've been told that it's possible to disconnect the intake on a cylinder and run a borescope in to see the cam. I haven't looked at an engine diagram to see if that makes sense yet.
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  #5  
Old 01-22-2013, 11:21 PM
BPoletti BPoletti is offline
 
Join Date: Dec 2012
Location: St. Louis, MO area
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Quote:
Originally Posted by jrs14855 View Post
IIRC on the four cylinder Lycoming two cylinders share a pair of cam lobes.
This would be the most critical area as these lobes are doing twice the work as the others.
Six lobes. IIRC, the second and fifth lobes are "shared" by the intake valves on the opposing cylinders. The other four are for the exhaust valves.
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  #6  
Old 01-22-2013, 11:27 PM
jetdriven jetdriven is offline
 
Join Date: May 2012
Location: Houston tx
Posts: 128
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If you pull two cylinders on one side you can use a flashlight and inspection mirror or a borescope to view the cam and all the lifters. Failure will usually begin with the lifter face, it will get slight pitting, then progress to all out lifter face breakdown and spalling. Then the cam will get rough and destruct.

We did this inspection on our airplane at prebuy and it looked great. IO-360A3B6D. Then 250 hours later we had 3 spalled lifters and a trashed engine. You can't see the small pits at the center of the lifter face, which we must have had.

We recently tore down a Continental E-185 which looked good. However, 8 of the 12 lifters had early signs of slight pitting. Its very small, but if the lifter faces dont look like chrome and zero scratching or pitting, its going to have to be split and the cam and lifters replaced.
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1977 Mooney 201
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  #7  
Old 01-22-2013, 11:35 PM
BPoletti BPoletti is offline
 
Join Date: Dec 2012
Location: St. Louis, MO area
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Quote:
Originally Posted by jetdriven View Post
If you pull two cylinders on one side you can use a flashlight and inspection mirror or a borescope to view the cam and all the lifters. Failure will usually begin with the lifter face, it will get slight pitting, then progress to all out lifter face breakdown and spalling. Then the cam will get rough and destruct.

We did this inspection on our airplane at prebuy and it looked great. IO-360A3B6D. Then 250 hours later we had 3 spalled lifters and a trashed engine. You can't see the small pits at the center of the lifter face, which we must have had.

We recently tore down a Continental E-185 which looked good. However, 8 of the 12 lifters had early signs of slight pitting. Its very small, but if the lifter faces dont look like chrome and zero scratching or pitting, its going to have to be split and the cam and lifters replaced.
Do roller lifters overcome this problem? Ney nozzles? (Don't mean to hijack the thread.)
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  #8  
Old 01-23-2013, 07:28 PM
jetdriven jetdriven is offline
 
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Location: Houston tx
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I can't speak for Ney nozzles, but I dont think they would. The damage is caused by a polished lifter face pitting from corrosion. The Ney nozzles would help with dry start scuffing and make the lifter run cooler, but does nothing for the corrosion.

We went with a factory Lycoming engine which does have roller tappets. Lycoming swears only two tappet failures (and they were mechanical, IE it came apart) at the beginning of the program in 2005 and to date, no cam failures.
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  #9  
Old 09-02-2013, 04:27 PM
rc454 rc454 is offline
 
Join Date: Sep 2013
Location: walla walla, wa
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Quote:
Originally Posted by jrs14855 View Post
IIRC on the four cylinder Lycoming two cylinders share a pair of cam lobes.
This would be the most critical area as these lobes are doing twice the work as the others.
What does IIRC stand for?
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  #10  
Old 09-02-2013, 04:35 PM
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Mike S Mike S is offline
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Location: Cameron Park Ca "o61"
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Quote:
Originally Posted by rc454 View Post
What does IIRC stand for?
Ron, welcome to the good ship VAF.

IIRC is "If I Recall Correctly"

This may help.

http://www.gaarde.org/acronyms/?lookup=F
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