I realize that getting a PPI from a reputable source is important, but I am looking to see if my initial observations hold weight with Lycoming/Continental aircraft engines, as they would with most other automotive engines. I would not want to do a PPI on unworthy candidates that I can eliminate myself.

I recently was interested in a local homebuilt airplane and the seller represented that the engine (IO-540) was 750 hours since new. The engine looked clean, seemed to run well enough, and he shared the results from itís last inspection. Compressions were in the upper 60ís and oil use was claimed at a quart every 4 hours. He then showed me a few images of his engine monitoring panel, while in flight, to illustrate his claims of speed and fuel burn. What surprised me most was that the engine was level cruising at 2400 rpm, at about 70% power, with the oil at 150 degrees and the oil pressure was just over 60psi. EGT and CHT both looked normal.

None of these items, individually, are disqualifying but when taken as a whole they seem to indicate that the engine does not have as much service life to offer before needing a major overhaul, as itís hours might imply.

Does this sound reasonable, or am I being too critical?