by Steve J » Sun Mar 07, 2021 12:50 pm
It's possible that the slight movement you feel when rotating the flywheel by hand is due to other causes.
For example:-
- Increased clearance between the piston rings in their grooves in the piston, which will allow slight vertical movement of the piston in the barrel, before the rings start to move.
This clearance will increase as the engine wears.
- Excessive clearance between the small end bush and the gudgeon (piston) pin, which also increases with wear.
- Backlash between the crank bevel gear and the clutch bevel gear, due to wear or incorrect setting during assembly.
Even with a newly rebuilt engine, it's possible that very slight movement may be detectable, due to the normal clearances between these parts.