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Jim Burns[_3_]
May 23rd 07, 08:45 PM
What do your JPI readings show?
Jim

Jim Burns[_3_]
May 23rd 07, 11:59 PM
Here's a WAG for conversation's sake. Is the EGT temp low on initial
start up / warm up, while operating at low rpms and or does it cool
down faster than the others on shut down?

Could the exhaust valve be sticking when cold, moving and wearing the
guide in the boss, causing increased oil usage and both aluminum and
steel in your samples yet showing good compressions after warming up?

Like I said, completely a WAG.

If you really suspect the cylinder, I would not fear pulling it for a
thorough inspection. You'd get immediate knowledge of the condition
of the piston and pin, the ability to examine the cylinder, the valves/
seats/guides, and check the rings, and even a peak at a few of the cam
lobes. A wealth of knowledge available for relatively minor $. I've
only had the need and the experience of pulling one cylinder, but
under an A&P's guidance I removed it myself in less than 2 hours and
we reinstalled it together in about 3 hours.

Easier and cheaper to catch a problem before it becomes a disaster.

Robert M. Gary
May 24th 07, 05:26 AM
On May 23, 3:59 pm, Jim Burns > wrote:
> Here's a WAG for conversation's sake. Is the EGT temp low on initial
> start up / warm up, while operating at low rpms and or does it cool
> down faster than the others on shut down?
>
> Could the exhaust valve be sticking when cold, moving and wearing the
> guide in the boss, causing increased oil usage and both aluminum and
> steel in your samples yet showing good compressions after warming up?
>
> Like I said, completely a WAG.
>
> If you really suspect the cylinder, I would not fear pulling it for a
> thorough inspection. You'd get immediate knowledge of the condition
> of the piston and pin, the ability to examine the cylinder, the valves/
> seats/guides, and check the rings, and even a peak at a few of the cam
> lobes. A wealth of knowledge available for relatively minor $. I've
> only had the need and the experience of pulling one cylinder, but
> under an A&P's guidance I removed it myself in less than 2 hours and
> we reinstalled it together in about 3 hours.
>
> Easier and cheaper to catch a problem before it becomes a disaster.

I've never had any symptoms of a sticky valve. In the 1000 hours I've
had this engine there have been maybe two times the engine has
stubbled slightly in flight (as a CFI I've seen this on many planes),
and its never had any morning sickness. However, I'm not sure if the
valve action relates to oil passing or not. Blackstone seems pretty
sure this is a pin plug. At first they said it could be the dip stick
but I would have been something on the stick by now. I guess if I pull
the cylinder it will be obvious where the oil is coming from??

-robert

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