So my O470J has two cylinders at about 55. The leak is past the rings. The rest are middle 60's on a 500 hour motor. These same two were a little iffy last year and I stopped running lower power settings but 50 some flight hours later and they are a little worse.
I'm debating the merits of two new cylinders versus pulling two and having them rebuilt. Down time is obviously a deal and nobody seems to have rebuilds on the shelf for my J motor. Sending them off sounds like it's probably three weeks or better. It's not a lifetime plane for me but I really like to feel like I'm doing things right whilst also being eternally short on cash.
Anybody want to weigh in with experience or opinion on which route is likely to be better?
Thanks

Check your master orifice on your compression tester and see what your minimum is. My bet is around 45/80 for your minimum. If you are above that and the leakage is dynamic(past the rings) and not static(past the valves), you are still within limits. It is common to see continentals in the 50s/80. It becomes a problem when you either notice performance loss, increase in oil consumption or find abnormalities on a visual inspection with a borescope. I had a long talk with the Continental Tech Rep regarding this subject. That being said, if you still replace the cylinders, I would buy 2 new ones, then have these 2 overhauled and stick them on the shelf for spares. Good luck!

What is your oil burn in 25 hrs. I would just run it if it is within limits. I have an extra new never run cylinder for an O470L. Guess if it were new it would have to be never run.

Tim

Why not just repair them?
Take them off and measure, hone clean pistons, replace rings if everything measures out alright.

IRAN?

.