[2winpistola]

Hi everyone, im in the mist of rebuilding a 4mm cub. One piston was damaged due to rod bearing failure, the other is fine, are both pistons needed to be replaced in order to keep things balanced or is that not nessesary. Id hate to buy another piston if its not needed.

 

[Mailman]

How many hours are on the motor? If it is pretty fresh then you may be able to get away with it but I would always replace both.

You would need to take measurements on the piston, rings, and cylinder bore to be certain if you really wanted to run the old piston but once again, I would not do it. I would have the cylinder lining inspected; hone the cylinders; and replace both pistons.

Hope this helps,

Mailman

 

[2winpistola]

QUOTE (Mailman @ Feb 21 2009, 07:33 PM) index.php?act=findpost&pid=31559How many hours are on the motor? If it is pretty fresh then you may be able to get away with it but I would always replace both.

You would need to take measurements on the piston, rings, and cylinder bore to be certain if you really wanted to run the old piston but once again, I would not do it. I would have the cylinder lining inspected; hone the cylinders; and replace both pistons.

Hope this helps,

Mailman
would piston ring wear be the most important thing to look at since they are what takes real wear-n-tear?

 

[Radar]

I've replaced one that was pretty new and just burned one up due to running a bowl dry. But if you are gonna want it to be perfect then two pistons and rings will be better of course. Make sure you dont hone a cub cylinder with a reg hone. They take a diamond hone.