Piston pin length
 

Currently in the middle of rebuilding/refreshing my '11 EC250. Well, first time looking in the box of my new S3 piston and it doesn't have a new pin with it. Ugh. Anyway, I have a CR250 piston pin that is the same in all dimensions except length as it is about an 1/8" shorter.

Question, could I use this pin without issue or would it moving from side to side cause wear or balance issues? I would prefer not to use the old pin, and don't want to wait on ordering one in, so was hoping this might work.

Never mind. I mic'ed up my old pin and it was still within spec so I used it.

If I recall correctly, an engineer at Wiseco said it is not ideal to have the pin shorter than the piston bore between clips. I think it was related to the pin moving laterally and potentially hammering on the clips. I am not sure where the force to move the pin laterally comes from so I dont really understand it. If it is not too late maybe a 1/16 thick aluminum washer (of the same diameter of the pin), or other suitable spacer on each side of the pin to take up the gap.

Thank you. I appreciate the info!

Probably the best move. I'd be very cautious about introducing any washer in the assembly.

There is a hell of a force on something being shaken up and down so fast. I've destroyed stuff trying to hybrid stuff on race engines to my shame.

Good point about the washers. Scratch that idea.