This kind of depends on which high compression pistons you used. In my O-200, I used the 8.5:1 O-200-D pistons. The O-200-D piston uses a Keystone ring for the top ring, which is only available from Continental at an incredibly high price. Rather than letting Continental hold me hostage, I machined the top ring land to fit the O-200-A ring and used the stock O-200-A rings. That worked well and as far as I know, the new owner is still flying with this configuration.
I built another engine using 9:1 pistons from Combustion Technology. Those pistons used the stock O-200-A rings. So far, no problems with them, although they don't have very many hours on them. They also made 10:1 pistons that used the O-200-A ring set. Combustion Technology pistons are no longer available as the owner retired and nobody bought the business. Light Speed Aero also makes high compression pistons for the O-200. I believe theirs are 10:1 pistons as well and use the stock O-200-A ring set. He insists that you must have new cylinders before he will sell the pistons. The only other high compression pistons are to use the C-85 pistons, then machine a bevel in the tops of the pistons to fit. That piston also uses the same ring set as the O-200-A and comes out to something like 8.5 or 8.7:1 compression. The tall dome on your pistons suggests they are 10:1 pistons. The two manufacturers that I know that made 10:1 pistons both used the O-200-A ring set. -Jeff Scott Arkansas Ozarks > Sent: Thursday, April 16, 2026 at 3:51 AM > From: "Phillip Matheson via KRnet" <[email protected]> > To: "Mustang Group" <[email protected]>, "KRnet" <[email protected]> > Cc: "Phillip Matheson" <[email protected]> > Subject: KRnet> High Comp pistons 0200 > > I have a set I removed from my engine , 6 months ago? due to low compression > in # 4. I found broken 2nd comp ring and top rib stuck in ring land. Also > another piston had stuck rings. Photo before and after cleaning today, with > hope of refitting in my new cylinders. > > > > > -Wondering if a many have used these with success? - or failure?? > Also did you use standard 0200 rings and stated on line, > - What problems have you had? > - any oil consumption or oki leak problems > Thanks > Phil matheson > Sent from my iPhone-- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet > -- KRnet mailing list [email protected] https://list.krnet.org/mailman/listinfo/krnet
