Some questions on superjet engine rebuild.

[skithis]

I blew up my 61x 701. I need new pistons, a bore, and a head. How big should I bore it? Is it worth boring over what I need or will the power gain not be noticeable? Also, Will the new pistons come with something that will tell the person boring what ring end gap and piston to cylinder wall clearances I'm looking for?

 

[227]

From your post it implies that there is damage to the cylinder walls. How much damage will determine weather the cylinder can be repaired by boring and how much boring is necessary. Boring over what you need alone is not going to give you any noticeable power gain. Use the smallest-oversize piston which will correct the damage to the cylinder. The actual boring size is determined by the new pistons size which you provide to the shop which will do the work. If you don't feel confident in determining what size new pistons to buy, you should consult your machine shop.