Which is better, a ringed engine or one that is ABC ?

depends on the Mfg.

i personally used ABC in competition free flight, bu prefer Ringed for my RC stuff.

also, post this in the engines forum and you'll get a lot more input on this subject.....

http://www.rcuniverse.com/forum/forumid_114/tt.htm

Buy the one you get the best deal on.

I may be a n00b but my answer would be the engine that is on my airplane at the time I want to fly it..

another way to look at this is that an ABC engine is more forgiving on a lean run than a Ringed engine is..........but if you don't give a little more info on what it is you want, this is a debate that can get into an ugly catbox fight

personally i think a ringed engine is a bit more durable on heavier airplanes.but to say one is better than the other,depends on the application.

Ringed engines will eventually need new rings. A properly run ABC will last indefinately. Now, it may be 600 hours of run time, so you might never get there.

My engines seem to die of other causes than old age. Like impact and sudden violent dissassembly. I've got one ABC (a TTPro46) I'm keeping going on life support. New carb and the second piston and sleeve but still running like a trooper.

abc engines have different problems than ringed engines,we are talking true abc not the abn that os produced.during breakin they require near max rpm to get the correct temp for the cylinder to expand,if too rich and the piston will wear,any dirt that scratches the piston or liner and you need a new piston/liner assenbly vs just a ring or piston and ring.had a freiend ruin a lee custom 7.5 k&b from a lean run in a f9f-8 Couger years ago,took rhe raper out of the cylinder when it cooled and lost all compression.most ring engines when they wear out can be re juvenated by replacing the ring.and since frank bowman makes rings after engines are out of production you can keep a ringed engine in service a long time.I have been using abc engines since k&b introduced the 3.5 in ducted fans.that engine stock in the rk-20 fan on 25% nitro on a pipe would turn 22,500 rpm,with the change of the piston/liner to a pipe tuned piston/liner the addition of a r.p.m machinded rod bushed a both ends a k&b .40 size carb and a robart matk lV pump it would turn 24,500 rpm and 8 ounces more thrust.