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> Last weekend, on my A&P's instructions I returned to Kentucky, got an
A&P
> form a nearby airport and performed the following checks.
>
> 1. Changed oil and checked screen. Found no indication of problems on
the
> screen.
> 2. Performed compression check. Results 72/68/68/68
> 3. Checked spark plugs for fouling. A&P said they looked fine
> 4. Performed Magneto alignment check. All ok.
At lease on the follow three things must be occurring:
You've lost cooling.
You've got bad readings.
You are generating excess heat.
Look for these and determine what, if anything is wrong.
1. Cooling: Check to insure that nothing has cause the baffles to change
or blocked the flow of air. A small change can have big affects. Look
them
over good, even if you think they are okay check them again. Remember,
also, that you need both a tight seal at the top, (High Pressure area),
and
a tight seal at the bottom, (Low Pressure area). Also all the cooling air
must be exhausted out of the cowl - no blockage. Are you flying in a crab
angle and inhibiting air flow?
2. Readings: Sounds like you had a predetonation problem. So it was
running hot. But just be sure. As already suggested, check the gauge and
the oil screen. A quick check without the other thermometer would be to
put
the probe end into boiling water. (Water boils at 212 degrees +/- a
little
for altitude. So it is easier to use for a check to see if all is okay.
To
calibrate you will need the other thermometer). Was there any metal in
the
old oil?
3. Excess Heat: You've check the compression and it looks okay.
a. Now take the plugs back out and turn the engine by hand.
Is there any tightness that shouldn't be there?
b. Timing, you've checked. Check again.
c. Exhaust pipes open and not venting inside the cowl?
d. I don't think the mixture could get the oil temperature that high.
You would have got a rough engine before it heated that far.
e. Just to make me feel good:
Did you by gas at the last stop?
Did you get 100LL or Jet A?
(Check it - don't believe it).
After most of this, I would look for something bad happening inside.
No metal makes me think more of a cooling problem or a fuel problem.
Let us know the final out come. Just for general knowledge.
Jack
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