Motor compression by hand???
 

Hey guys.

I bought a O.S RG .21 from a guy that said it had new bearings and was pinched.

With the flywheel on how hard should it be to turn the motor over?
I can turn it over almost with ease. There is a bit of resistance at TDC.
Not alot? The motor has not been ran since the pinch. Should it inprove?

What about a higher end motor like a RB. Should it be able to tunred over by hand?


Thank you for all your help.

If it was pinched, it should have resistance when close to TDC. If it was a light pinch, with no metal scratchiness at TDC, then it should have a lot of compression, and should push back when spun past TDC. Turn & hold the crank at the compression point and place the engine body at a 3 o'clock position. If it has good compression it should hold the engine case at the 3 o'clock. If the compression is low, then the engine will continue to turn and end up at TDC.

Great tip... The motor makes it way down from the 3 o'clock postion. Does that mean the pinch is no good?

Yes, the pinch is no good. After a pinch or on a good motor, the engine should hold the 3 o'clock position by either compression hold or by piston to sleeve pinch tightness (new engine or fresh pinch).

want to unload the engine? i am in need of some parts