The International Cessna 170 Association

This isn't 170 related, but with the knowledge of our members I think someone can clarify this question. I was told a Continental O-520/IO-520 is basically an O-470 with larger cylinders and a O-550/IO-550 is also basically an O-470 case with 550 cylinders.
That source stated the 520 & 550 engines tended to have more cylinder,etc issues than the O-470. ??

PPonk has a mod from 0-470 to 0-520

http://pponk.com/engines/

Having owned both a 520 and 470, I'd say it would be hard for any engine to have more cylinder issues than those. As far as I know, the 550 is more of a clean sheet design that runs cooler and has better cylinder life, but I have no direct experience.

I owned a pair of IO-470's and had no particular problem with them despite running them hard and long. But I have to say those engines, especially on older aircraft, are often fitted with "repaired" or "overhauled" cylinders rather than new cylinders and that is what I believe gives the cylinders a bad rap.

Also, there are some significant differences between O-470 and IO-470 engines, and even WITHIN the IO-470 engine line, there are at least two major versions of that engine in which virtually NOTHING is interchangeable. The point is, just because someone praises...or curses their 470 engine...gthe remarks should not be taken as applicable to all versions. The IO-470-L engines are prolific and well-known to be some of the best and most durable aviation engines ever.