<VV> Compression test and Cylinder leakdown test

[Sethracer at aol.com]

In a message dated 8/15/2011 6:53:57 A.M. Pacific Daylight Time,  
kenpepke at juno.com writes:


In  addition, the 'leak down' test provides one the opportunity to listen 
at the  tail pipe for valve leaks.
Ken P





A compression test (even though a pain to do - especially on A 140)  will 
point you in the right direction. If all cylinders are close and a  
reasonably high number, say 125 or above, look elsewhere for running problems,  fuel 
or spark, probably. But if one cylinder is lower than the rest, the next  
test should be a leakdown test. Pumping air into the cylinder (with the piston 
 at TDC) will show some leakage. A burned or bent valve will show up as 
noise. An  intake leak can be heard through an open throttle plate, and exhaust 
with  the sound out the tailpipe. Piston deterioration or piston/ring 
breakage can be  heard via the oil filler (with the cap removed). At this point, 
if you can  hear it, you have work to do!
 

Seth  Emerson

C's the Day! - Corvairs, Camaros, Corvette
San Jose,  CA