Piston pin length

[SS109]

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.

[Zman]

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.

[SS109]

Originally Posted by Zman

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!

[(F5)]

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.

[Zman]

Good point about the washers. Scratch that idea.