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Lycoming Valve Wobble Test?

skeptic

I'm New Here
How many of you are accomplishing the valve wobble test every 400 hours as recommended by Lycoming SB 388C?
 
I Just Finished Mine

HR II IO-540-C4B5 800+ Hr. Total Time

Just finished my second one - didn't find 'nuthin!

HFS
 
Thanks. I have been shopping around for a flying RV-7 (hope to build one of my own in the future). Most of the airplanes I have inquired about have not had the valve wobble test accomplished. I was just wondering if for some reason people in the RV community had decided that the test was not necessary? I personally would probably not want to own an engine that had gone more than 500 hours without the test.
 
I have the tools and have done the test. On my own airplane, I wait till I have higher oil consumption or poor differential compression with leaks through the valves. Then will do the test. I do not tend to go looking for things wrong unless something is wrong.
 
I have the tools and have done the test. On my own airplane, I wait till I have higher oil consumption or poor differential compression with leaks through the valves. Then will do the test. I do not tend to go looking for things wrong unless something is wrong.


Exactly... also, many are not even running with factory Lycoming cylinders and/or parts that had the original concern.
 
Exactly... also, many are not even running with factory Lycoming cylinders and/or parts that had the original concern.

My factory reman engine with new Lycoming cylinders failed on the too loose spec. after about 650 hours.

It did use the newer, harder valve guides.

Other O-360s I have checked were in the middle of the tolerance after 2000 hours.
 
Exactly... also, many are not even running with factory Lycoming cylinders and/or parts that had the original concern.

IIRC some of the concern is how much oil is getting pumped up the pushrods to the valves - which is not cylinder manufacturer related.
 
Clicked on the link, but got this result:
Not Found

The requested URL /support/publ...fs/SI1485A.pdf was not found on this server.

Apache/2.0.52 (Red Hat) Server at www.lycoming.com Port 80

The "..." in the actual link doesn't help....:)

Try this one

http://www.lycoming.com/support/publications/service-instructions/pdfs/SI1485A.pdf

It's the SI that identifies the harder material valve guides I mentioned in post #8. Even though it calls for 1000 hrs to the first test, mine failed at 600 hrs.
 
Last edited:
Another data point.

A 2008 factory Lycoming 0-540 needed one valve reamed after 950 hours. Had not been done since new.
 
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