TBO etc et al

[n86121]

Good Morning Fellow Thrasherists!

I've had my T337 for fifteen years, with a nearly new engine out front (TCM new), and about 1,200 hrs on the rear. I do not expect to sell the airplane for many moons, if ever, so 'TBO' as a market value consideration is nil to me.

My strategy has been to replace any cylinders on the rear as they get weak with NEW TCM cylinders (no metallurgical cycles), and have replaced all of the fuel lines, injector lines, etc. I've done four out of five, and am about to replace yet another. Except for the one about to go, 66/80, the rest all show 74+/80.

Is 66/80 worth worrying about?

I run 50 hour oil samples, and have for years.

My belief is that I can keep the top end of the engine fresh this way, and oil analysis will pick out anything starting to wear on the bottom end.

Years ago I spoke with a TCM guy, who felt this was a reasonable strategy.

I also know a fellow who states that he used to fly for a check carrier that used a bunch of T senecas, (same engines) and they just kept swapping cylinders, and had better than 4,000 on the bottoms ends.

Am I crazy, or does this make sense?

(Perhaps two unrelated questions...)

David Wartofsky - Potomac Airfield
www.potomac-airfield.com