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Old October 7th 08, 06:39 PM posted to rec.aviation.owning
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Default Can hydraulic lifters cause inadequate full power?

Orval Fairbairn wrote:
: You would HEAR tappets clicking if you have bad lifters.

: Cams in Lycomings tend to corrode on the front lobes over time, with low
: usage. One way to check is to pull the valve covers and check the valves
: for proper movement as the crank turns.

: Check the logs for cam replacement at overhaul.

The overhaul had yellow tag for the cam. Put a dial indicator on the cam last year and it came up at 0.353 +- 2 on all lobes... that agreed with a friend's brand new
PMA's cam lift. I'm fully convinced the cam is fine.

If the lifters had clogged valves, I'd agree that you'd hear them, but excessive leakdown maybe not? Like I said, I don't *really* believe this is the problem, but I
didn't believe the dry tappet clearance would affect anything either (but did). We've checked everything else anyone's ever come up with (check my post from a week ago).

Thanks,
-Cory

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* Cory Papenfuss, Ph.D. Electrical Engineering, PPSEL-IA *
* Research Associate, Vibrations and Acoustics Laboratory *
* Mechanical Engineering *
* Virginia Polytechnic Institute and State University *
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