About 70% of overhauls buy new cylinders instead of overhauling their existing.
If you decide to overhaul your cylinders, you may want to ask your shop if it’s your cylinders getting overhauled or someone else’s. If they are not your cylinders, you should insist on them being first-run cylinders (meaning it’s their first time being overhauled). But since there’s never any real ‘proof’ that cylinders are first run, request the following:
- Standard barrels
- Non destructive tested heads
- Valves, guides, springs, keepers, piston, rings, and piston pin are replaced NEW (don’t reuse this stuff)
- Verify there’s no weld repairs on the cylinders
If you go with new cylinders, you’ll have 3 options depending on the exact type of cylinder:
- Factory (Continental, Lycoming, Etc.)
- ECI (Purchased by Continental in 2015)
ECI no longer produces Continental parts. Only Lycoming and experimental.
Aviation consumer did a survey on new cylinder reliability and satisfaction back in 2008.
The survey results are pretty dim. Only 13% of Continental cylinders made it to TBO, 63% of Lycoming, 72% of ECI, and 68% of superior. Keep in mind the survey is pretty old and only had 277 respondents. But it’s the best third party source I can give you at this time. Aviation Consumer Magazine came out with a new survey in November of 2015 but you have to be a subscriber to view it.
Most of the shops I’ve spoken to still report Continental cylinder troubles though a few have said they’ve improved. The main complaint I hear is that the choke wears out within 350-750 hours which forms a gap between the rings and the cylinder wall. Oil blows by the rings and you lose compression. Second to that were comments about valve guides wearing out prematurely. The flipside of this argument is that it’s either a result of the operation (excessive leaning and downtime) or that it’s an old opinion that has been circulated longer than the problems have existed.
But, here’s some perspective. Factories have pushed down pricing to compete with overhaul shops for business – especially Continental. This has put downward pressure on overhaul shop pricing and profits. Consequently, shops may have a bit of bias in their opinions about the factories. But, I think shops care more about making sure the customer is satisfied than they do about this possible bias. And remember, they’re the ones that are going to warranty it so they have an interest to steer you in the most reliable direction. You can’t argue that that self-interest.