I recently acquired an OPS .60 engine. I'm not sure the model, it has a red cylinder head, and is a front intake with a transverse slide venturi carb. Has a header for a pipe, but I do not have the pipe. I think these were popular pattern engines back in the day. It had been sitting unused for quite a while, so I've been carefully taking a few parts off and finally got it loosend up enough to turn over. I took off the back plate and cylinder head, and notice that even without the head, it has a considerable "bump" when going over TDC. Is this normal for an ABC engine? I've heard they are very tight at TDC when cold, but I've never owned one before, so don't know. The cylinder, piston and head don't even look like they've been run (no burned oil stains) but the pipe header does, so I'm pretty sure it probably was. I'm not interested in running or flying it, just want to get it cleaned up enough to try to sell it to someone who might be interested in one of these. Otherwise looks almost new except for the pipe header

Classic OPS engines are always of interest to the classic pattern community. Be careful when dissasembling it -parts are very difficult to come by. And yes, ABC engines have conical pistons and are indeed very tight when cold. The Italian brutes were especially so.

Please post some photos and perhaps you can post it for sale on the market place.

David.