Re: Piston removal without removing engine?

> There is a slight layer of rust where the piston meets the > cylinder wall. > > Without removing the engine, is it practical and good practice to > remove the affected piston by accessing from the oil pan and > pushing the piston up through the cylinder? I would Like to > hone the cylinder walls while the piston is removed.

Um - don't confuse a little surface rust with major dammage. If that rust is really bad enough to cause problems with that piston or cylinder then you better toss the engine back into the ocean where you found it.

Seriously, removing one piston just because of a little rust ia not recommended. If you took the head off to do a valve job or replace a head gasket then you'll double or tripple the amount of work just to take the bottom end apart to pop out one piston. That, plus honing just one cylinder is unheard of. Might also have some balancing issues unless you replace all pistons as a set.

Yes, knocking out a piston from the bottom is the typical way to do it.

I assume that the engine had a head gasket leak and sat for a while with coolant in the cylinder, old coolant that had lost the rust protection in it. If so, the rust might simply be surface rust. You would be better off cranking over until the piston was at the bottom, then cramming a rag tightly down into the bottom, then using the finest steel wool to get rid of the rust. While you are probably going to lose some sealing in that cylinder, eventually the cylinder wall and piston ring will wear in and help that a bit. At least it will get the thing running well enough to sell off. Otherwise you ought to pull the engine and rebuild it. By the time you get the thing torn down and the pistons all out and hone all of the cylinders, you could have pulled the block out and sent it to a machine shop that could bore the cylinders true again.

Ted