Was given a chev 350 (couldn't argue with the price!) was told there was water in the oil... I'm hoping just a head gasket not a cracked something. I find 040 stamped on the pistons. My question is, at .040 over is the engine worth rebuilding? Assuming there is no other bigger problem. Thanks for taking the time.
Maybe, maybe not. If you have a use for the engine, and can't find a better core, and nothing is cracked, then it might be worth it.
I would not bother, even though some rebuilders are saying core 350s are getting a bit scarce. The water in the oil, plus already 40 over is the reason. If you did find a simple reason why the water went into the oil, and if it does not need rebore, then maybe i would.
How are the cylinders? If no more than .007 wear you can use the old pistons with new rings, no need to rebore. Check it out, see how it looks. If the crankshaft is good and the cylinders are good, no cracks in the block, etc you may be able to buy an overhaul kit and be back on the road for very little dough. .040 by itself is not scary, max overbore is .060 so you are well within the limits.
the only way to know for sure is to take it apart and do an examination. if there is any noticeable cracks in the blocks it's junk...find a different one. small cracks you will need to magnaflux to find the water in the oil could be from something simple like a bad intake gasket..it has happened to me as already said , you have one more bore to .060. while there is nothing wrong with that , i personally like to stick with the first overbore at .030. that way it gives you one more rebuild
Thanks for all the help. Have the engine down to bare block, bores look ok to me. Only some small ridges at the top (7 pistons came out easy, 1 was a little more work). I guess its off to the machine shop to look for cracks...
If you don't want to spend a lot of money on it you can buy a rering kit with rod and main bearings from http://www.northernautoparts.com/ProductDetail.cfm?ProductId=148 for 80 bucks. I've run one in my 71 GMC for the past six years and about 70K of driving. You have to make sure you tell them the ring and rod and main bearing sizes. Make sure of the year first though.
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