new cam old block

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a100addict

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hey guys this is my first post so take it easy on me . i have a 318 rebuilt aboot 6 years ago. the guy i got it from never ran it and apparently must have left the hood off. i finally got round to putting it in a100 van. decided it would be a good idea to freshen up the gaskets. went to turn over the motor and it only goes so far. turns out two of the cylinders have rust damage. it was all bubbly and flaky.it has everything new. 30 over pistons new cam oil pump pushrods lifters etc.i am pretty sure it will not clean up with a ball hone.and i am on a zero budget. i also have a 318 out of a 86 truck. about 120k on it. so my question is can i use the new cam ,lifters.pushrods heads oil pump timing set on my old engine. the old engine ran awesome in my truck and only had a bad timing chain. in my head it should work does anyone have any exp with this ?.
 
I'd guess it depends on your plans. If you plan on coming up with another engine to build, or bore the water damaged one, even if you only bore the damaged holes, I would not put the new parts in the old engine, except for fixing the timing drive.

On the other hand if you figgure this 120K engine will "be there" for awhile, then knock yourself out. Just be aware of stuff like oil pan/ oil pickup fit, etc.
 
what is the opinion on boring 2 cylinders bigger. will it cause a imbalance? will a machine shop do it? can i buy just 2 pistons? how much will it cost on average. i have been underemployed since march but start a new job on mon. while i have to catch up on bills. if i am wasting my time i suppose i could wait a couple more mos and try to save up ?
 
I wouldn't bore only 2 cylinders out. Yes, this would cause an in-balance in the motor.
You could move the cam/lifters/pushrods/oil pump/ heads over to the other 318 block, you 'll just have to swap out oil pans....not sure if the van pan is a rear sump or not, if it is I wouldn't worry about it.
Make sure when removing lifters from new block that you keep them with the lobes they were riding on, they were "broke in" that way so they are "worn" to a specific pattern on the lobe. That's if the motor was broken in.
Do you know how well the oil pressure is in the 86 318? If oil pressure is good, then I wouldn't be afraid to do it at all.
 
Boring 2 cylinders wont cause an imbalance, oversized pistons weight the same as std as long as you keep within manufacturer. Theoretically, they will produce more power due to the increase in size, but I wouldnt sweat it in a van. How bad is the damage? You can get by with a good hone and some new rings as long as the rust was just surface.
 
Having two oversized cylinders won't create an imbalance? Didn't know that. I figured having two pistons that are bigger than the others means they would weigh a little more (prob a few grams) so the engine would have to be balanced (internally or externally) to make up for the difference.
But I guess if we'retalking .010-.030" that really isn't that much.
 
i ran a 120 ball hone through it. it is still catching my fingernail. i think i will throw into the van and take it by a machine shop. anybody know a reliable shop in the pdx area??
 
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