ORIGINAL: MOTORMAN37
ORIGINAL: BillS
My TH 75 engine was very tight and I preheated it before starting it on the bench. I also relieved the cylinder to piston clearance before running the engine. Will do it again if an engine will not turn over to my satisfaction when cold.
Long time mechanic and Mechanical Engineer.
Bill
I understand the preheating you did, but why would you mess with the fit?
I am also a mechanical Engineer.
The fit will loosen up a little after the first run, and reward you with High Performance.
My Tower .75 with the highest time (13 + gallons) still has enough compression, that you can grab a blade and pick the plane up on one side and hold the tire off the ground untill you get sick of holding it, and it will not bleed down.
Frankly it appeared that the final tumbling process created some slight burs on the top inside of the cylinder, probably a result of the tumbler being loaded with too many parts. In any event the fit was not to my liking, I had already paid for the engine, and the maximum exposure was only $110.
Bill