OPS .67 engine question

[dallasfan207]

I'm new to large engines & bought a used .67 OPS in a boat. When the piston nears tdc it carries the sleeve with it. Seems to move @ 1/8" or a little more. I've never had a motor with a sleeve. Is this normal or do I have a problem on my hands? Can it be fixed? Thanks

[BoatDoc]

that's because of the fit between the piston and sleeve. most sleeves are tapered slightly. once the head button is bolted down, everything will be held in place just fine.

[engineman351]

Dallasfan...As BoatDoc said, this is normal in the non-ringed sleeved engines we use in the RC hobby. One extra thing I will mention is that on the OPS .67's I have had apart, they do not use a locator pin to align the sleeve to the case. You will have to make sure you align the exhaust port of the sleeve with the exhaust opening in the case, then bolt the head on to hold the sleeve in place. If you miss this step, and the sleeve is not aligned, the engine may not start. If the engine runs at all, it will not develop any power. RC