-----------------snip---------------
If you are going to ground run it you want to bring it up to operating
temp. It's the short runs that not only don't evaporate much of
anything they put a lot more *stuff* into the oil as the cold engine
isn't running as efficient as a warm one and the byproducts can
condense inside.

Find a good clean spot on the ramp, let the engine warm up normally.
Then stand on the brakes and wind 'er up for a prolonged run. Of
course then makes the neighbors unhappy.

at least get the temp needle off the peg. If, for any reason I was
unable
to run the engine frequently, I would certainly place dessicant packages
in
the intake(s), exhaust(s), and crankcase breather.

---------------snip-------------------
If you feel the need to get the oil moving in a stored engine, crank
it over with the fuel and mags shut off untill full oil pressure is
acheived, then recharge the battery. Do NOT ground run for short
periods without getting the oil temperature up to dry it out.
Particularly important with top-cam engines, as the cams and tappets
are very prone to condensation induced corrosion failures. And worse
with Synthetic oils than standard petro oils.

The top cam engines are exactly the problem, which is why I really think we
are going around in a circle. And we are not the first to do so, nor will
we be the last.

In my admittedly limited understanding of top cam engines, the lobes and
tappets are essentially "splash lubricated" in that their coating of oil is
primarily by oil thrown from the crankshaft. In the case of Lycoming
engines, I presume that the intake lobes would receive some oil that could
travel from the camshaft bearings; but I am not convinced that the exhaust
lobes would receive any lubrication at cranking speeds.

Admittedly, there are direct spray modifications available for the Lycoming
cam lobes--according to a bonafide Lycoming Bigot in my chapter who has no
intention of ever flying his airplane at night or under IFR. However, I
have no adea whether the modification is certified under 14 CFR part 33. In
the case of Experimental Category and Day VFR only, presuming that the
modification was part of the original construction, the problem is solved:
just turn off the fuel, crank the engine, and recharge the battery. If the
aircraft is certified under 14 CFR part 23, or if IFR or Night VFR is
included, then my reading of AC 23-11A suggests that the engine as currently
installed is expected be certified and airworthy under 14 CFR part 33 and
the propelled as installed is expected to be certified and airworthy under
14 CFR part 35.

If we simply knew on the last day of good flying weather that it was time to
pickle the engine for the off season, the solution would be pretty simple.
However, other posts in the thread have elaborated that this is not
necessarily the case, and in fact the issue of preserving the engine is
likely to come up at the least opportune time. I admit that part of the
foregoing point escaped my attention as well, and I stand corrected.
Engines do breath in and out with changes in both temperature and barometric
pressure, and a ground run in the rain was really not a recommendation.

Peter

Disclaimer: this is not my occupational specialty and I don't recall why I
happened to read AC 23-11A. Also, if your airplane is registered outside
the US, different rules apply. Also, this is entirely redundant as you
already know by reading the thread; however everyone should go back and read
it again.
Alternate Manager of Duplication
The Depeartment of Redundancy Department