Jay, your first conclusion was that remanufactured cylinders were the problem. Then you concluded that running the engine at 2600 rpm's was abusive and was the problem and because of that, you're gonna set your requirements to C/S only.
Basing big conclusions on a sample size of one may not be your best approach.
And then we have the conclusion that buying a homebuilt is more complex than buying a factory built.
I'm starting to think you're looking for a reason to not buy an airplane, as opposed to looking for a reasonable deal, then making that airplane yours...
Lol! In a buyer's market, prebuys are, by design, a grueling elimination game. There is no need to accept anything less than perfection right now, and I am in no hurry.
My reasoning behind the constant speed prop decision was edited for brevity, but the two major reasons stand. Noise in the cockpit is much higher with a fixed pitch prop, unless you dial the power back -- which results in speeds in the 140 knot range.
Since my current ride is already a 140 knot aircraft, this would leave me with a bad choice of, essentially, go fast or go quiet.
One goal in buying an RV is to be able to get back to Iowa in significantly less time. The thought of enduring those high RPM noise levels to/from Iowa (or OSH) is a bad one, and led us to the elimination of any plane with a fixed pitch prop in our search.
WRT the burnt valves, that was pure speculation, suggested in another group I'm in. It makes perfect sense, however, given the seller's mission of formation flying, which requires high RPMs/power (to keep up with the CS equipped RVs), and constant power changes to maintain position.
This is not the kind of flying where engine management is your primary concern. A little too lean, and you're gonna cook those valves.
This seems like a logical explanation for having three bad cylinders on a bulletproof O-360 in just 500 hours. And the "good" one had compression in the low 60s, so it's not long for this world, either.
The other possibility was a crappy engine rebuild. We know the original builder "went cheap" and rebuilt the old cylinders. In my opinion -- and the opinion of every A&P I know -- that's false economy.
Either way, for whatever reason, the guy's engine is trashed. Did it take the camshaft with it? If so, you're looking at a very expensive proposition, indeed.
So, we're on to the next ones.
