Crankshaft Play
 

Hello

just finished doing a bottom end rebuild on my EC 300 2002 new main bearings seals and conrod installed all went together well and spins freely and selects gears well.

This engine does use the roller type bearing on one side the bearings where with c3 cleareance.

The question is there appears to be quite a lot of play side to side in the crank as in moves about in the cases but no vertical play i haven't attached anything onto the crank yet like the primary nut or flywheel would this and refitting the piston and cylinder solve this problem ?

First time doing this so didn't want to go any further in case i have done something majorly wrong ?

Any help appreciated

Matt

Forget your fears. Zip it up and enjoy.

Okay i will try.

Its just that this thing does seem to have a lot of end play and the cases went together like a dream which makes me think the actual diameter of the crankshaft is worn away which is allowing that in and out movement i describe.

Am i on the right track..or is this just a normal thing for an old gas gas ?

Normally the crank would be a snug fit in the bearing and would not move back and forth. In reality some movement is not a big deal. Other machines that have roller bearings on both sides of the crank always have some end play. This would be .005 to .010 inches. Have you measured the actual play?

If I understood everything right the crank moves from side to side not back and forth.

Yes you are correct the movement is 1mm it moves fully from one side of the case to the other.

It is definitely the crank moving and not the bearing moving in the case the more i think about it the less issues i think this could cause but I'm a novice at this.

Picture of the crank it moves from side to side till.it hits the case

Movement is not an issue but it should not actually be able to rub on the case while it rotates.

Is the rod big end narrower than normal? Does the crank pin project out each side of the flywheels? 1mm (.040") movement is large. Is there any change a shim was missed on reassembly? Meaning a shim between the flywheel and inner bearing race. It is normal to shim the crank bearings to reach a nominal reference width.

From what I see from the picture the crank touches the case and that is a no-no. 1mm, as Neil already said seems to be too much imo.

Did you change any parts? Casings or crank? Have the bearings the same width as the old ones?