On Sep 17, 12:41*pm, Charles Talleyrand wrote:
My local mechanic says that I need to overhaul my engine. *It's got
1200 hours but it's been 27 years since the last overhaul. *He's
worried about the age, and he hears "piston slap" when he runs the
engine. *Compression and oil analysis are fine. *He is well respected
around the local airport.

He proposes either a name brand $16,000 overhaul, or a less costly
option where he and a local aviation mechanic professor can work on it
together ("two eyes are better than one" he says).

If it makes a difference, I don't live in farmland. *I live in the
forest, with forest and lake for 100 miles in every direction.

Any advise? *Any way to explain to the wife? *Anyone want a nice C-150
with a new paint job but a tired engine?

Those little Continentals have a weak top end. At 1200 hours
it's not unusual to need a top overhaul: rings might be OK but the
valves should be cleaned up and the lifters will be sludged up and can
be cleaned from the outside of the case. The mechanic might be hearing
valve clatter rather than piston slap, and when the cylinders are off
the dimensions can be checked to eliminate that anyway. I'd bet that
the last overhaul was a hone-and-rering job and that the cylinders are
at service limits now, maybe even .010" oversize and would need
expensive replacement with new ones.
Sludged lifters are cause by too many short flights or running up
on the ground. Crankcase condensation mixes with the oil and creates
sludge (bad) and acids (really bad). The cylinders might be pitted.

Dan