Engine balance

[Steve D.]

I am going to reassemble a small block using the same pistons and rods that came out of it. The pistons are FM L2166. I was told that pressing the pins out to separate the rods and pistons for balancing would more than likely damage the pistons. There is no visible evidence of metal removal on either rods or pistons to suggest an effort at balancing when the engine was previously assembled.

Is piston damage a certainty if the pins are pressed out? If so, then I either don't balance and reassemble the engine, or spend $400 for new pistons. Comments and sage advice appreciated.

Steve

[Clem Z.]

Re: Engine balance

a good shop can press out the pins with no danage to the piston but you should rehone the pin bores in the pistons before reasembly because the pressing will distort the pin bores in the pistons. the pistons should be installed by heating the rod pin end NOT by pressing the pins back into the rods.

[Rob A.]

Re: Engine balance

Most shops actually have a price sheet for just that, removing and refitting the pistons. It is a common procedure and if the shop you use suggests they might be ruined in the process I would question their integrity. I recently had my engine balanced and the pistons removed from their rods and refitted. Make sure you get a price in writing for all the work you are having your shop do before you drop your engine parts off. If you decide later, for instance to have the flywheel and/or pressure plate balanced the cost will be more than if you had it all done at once.