Originally Posted by
countilaw
I have O.S. Max engines that are over 36 year's old. I've never had to change a rod. I have changed the bearings every couple of years. Of course I never leave fuel in my engines and always use Marvel Mystery Oil after a days flying.
Also, the lower rod end should a very small amount of play. I think it was Clarence Lee that stated that the little amount of play is what lubricates the bushing. And if anyone knows about engines, it's Clarence Lee. You can catch his articles in Model Airplane News.
Frank
Not having to do a lot of maintenance on an engine is one of the benefits of aircraft engines. Car/buggy and boat engines routinely need new bearings along with pistons and sleeves due to the much higher RPMs they operate at. In the boats I run, getting more than a year on a set of bearings or more that three or four from a piston and sleeve would be a borderline miracle. Then again, my marine .21s run at 35K while my .67s run at 28K, running on 50% nitro, something not needed in an aircraft engine