I think I spelled a few words wrong there, but hopefully got the point across. Anyways, here's my question. I've got a stock 350 longblock from my wrecked car that was rebuilt about 15k miles ago. If I want to use it as the basis for a buildup, will I most likely have to have machine work done? Maybe it is sort of an "If I do this, then I will need to machine it, but if I only do this, I won't" thing. I'm not sure. Can somebody tell me when/under what conditions machine work is needed? Will the cylinders need to be bored or honed if I want to replace pistons, no matter what condition they are in? Thanks ahead of time for any help. Just looking for suggestions. Who knows, maybe I should sell it and start from scratch with a new block. Thanks.

 

When installing new pistons you may get away with a simple honing just to put some crosshatching back into the cylinder walls. It will really depend on the diameter of the cylinder bore. Pistons need a specific clearance between the piston and the wall. If the walls are already too wide then oversized pistons are required. At 15K I'd say that the initial crosshatching is gone but I doubt if there's any noticable wear to the cylinder walls.

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87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

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87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

I had a 350 stroker engine that came out of a wrecked TA years ago.
THe engine sat in the wrecked car for almost two years before I bought it.
I had everything done to it.
All they did was hone the block and then installed the same pistons with new rings. It ran fine and never gave me a problem.

I would say, go ahead and tear down the engine and do it right the first time.

It would really stink if you get the motor installed and then something go wrong. Then you get to pull the engine and do the work anyway, and you have just wasted all that time on the install.

Like they say....
If you don't do it right the first time...then you'll do it right the second time.

As for being bored....
It would only need to be bored if there is a scratch in the walls or if you want to go for bigger displacement.

Gaskets and rings are cheap enough, and the machine work would be worth the effort.

That's what I would do if I had your situation.

 

The motor I'm presently building had 3,000 miles on a +30 bore and it needed to get bored again. The ridge on top is a sure sign. Also taper and concentricity factor in. A simple spring loaded hone is a waste of time if these are out of spec. My machine shop charged me 50 for hot tank, 40 for cam bearing install, 90 for bore and hone, and 10 for tapping the oil passages for screw in plugs and clearencing for a double roller chain. He also inspected the mains and align honed it for free. Nice guy!



[This message has been edited by JoelOl75 (edited August 07, 2001).]