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Old 03-16-2008, 01:19 PM   #1
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Default SBC help

when the weather breaks, i will be soon working on a 350 for my s10. i have it down to the bare block. but when i took out the pistons, i made the mistake of not marking which cyl they came from. so i now have a few questions.

1- is there anything i can do?
2- can i measure with my micrometer, and figure out their original cyl (not likely)?
3- and if i buy new pistons, do the rods have to go to a certain cylinder too?
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Old 03-16-2008, 01:37 PM   #2
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With a good honing, and new rings you shouldn't have a problem. Same with the rods, if new bearings are installed, it should be ok. Not ideal, but ok.

But if you want to do a real good job, bore out the cyls, put in new pistons and rings. Chances are that it should be bored out anyway to get it back to a proper round shape.

I guess you're finding out how the $$$$$$ add up in an engine rebuild, huh?
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Old 03-16-2008, 06:29 PM   #3
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Quote:
Originally Posted by JMH1950
With a good honing, and new rings you shouldn't have a problem. Same with the rods, if new bearings are installed, it should be ok. Not ideal, but ok.

But if you want to do a real good job, bore out the cyls, put in new pistons and rings. Chances are that it should be bored out anyway to get it back to a proper round shape.

I guess you're finding out how the $$$$$$ add up in an engine rebuild, huh?
i got a set of rings, they are just oe, not overbore.
so, you think using the original pistons would be ok? im not planning on running any sort of forced induction, just a decent flowing n/a..

keeping in mind that i have never honed cylinder walls, should i go with the bottle brush honer, or one with the stones?

and yes, i definitely realize how easily you can spend some loot on just the bottom end, let alone the heads.
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Old 03-16-2008, 06:39 PM   #4
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I assume this is going to be raced or worked hard?

I'd go ahead and get new. A set of forged pistons won't set you back that much. And if the originals have a lot of wear and you mix them up, you could run into trouble pretty easily.

The nice part about the SBC is the depth of the aftermarket. You can find good parts for half the price that you'd pay for any other engine.
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Old 03-16-2008, 11:31 PM   #5
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Quote:
Originally Posted by GonneVille
I assume this is going to be raced or worked hard?

I'd go ahead and get new. A set of forged pistons won't set you back that much. And if the originals have a lot of wear and you mix them up, you could run into trouble pretty easily.

The nice part about the SBC is the depth of the aftermarket. You can find good parts for half the price that you'd pay for any other engine.
no, it won't be worked too hard at all. it is only a swap of convience. i had a 350 that needed to be rebuilt. and the 4.3 in the truck also needs to be rebuilt. and after pricing the rebuild kits, and parts between the two, it was cheaper to rebuild the 350.


these are what i was looking at. http://store.summitracing.com/partde...0&autoview=sku
they're not that bad i can afford $80, but will i be ok with the rods, in different locations?
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Old 03-17-2008, 01:13 AM   #6
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The primary concern would be weight differences between the individual piston/rod pairs. If you are having the crank refinished or reground, in my opinion it is best to have the entire reciprocating assembly balanced. It shouldn't break the bank and since you already have it all apart, it will be good insurance if you expect to put many miles on it.
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Old 03-19-2008, 08:35 PM   #7
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Quote:
Originally Posted by samueljackson
but will i be ok with the rods, in different locations?
That'* a sticky problem. Messing up and not marking which rod & piston came out of which bore is pretty common.

Worst problem is mixing up rods and their caps, or mixing up main caps...which is a real bear to figure out.

So, assuming you have the correct rods and their matching caps, you are not *.o.l..you just need to hand the whole thing over to a machine shop and have the rotating assembly re-balanced...that will correct any imbalance caused by mixing up the pistons and rods. They will hand it back with the punch marks to tell you which piston & rod goes in which bore.

If you are new to rebuilding motors, then turn the block over to the machine shop as well. Let them boil it out and inspect the bore diameters and taper. If you go through this much work, you might as well put together a motor that will spin for 100k miles instead of just a simple re-ring.

Just food for thought. I know people who just reassembled the motor any old way and it still ran well. ( Sometimes the tolerances are held so well at the factory that swapping parts around does no real harm.)
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Old 03-19-2008, 09:00 PM   #8
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double check at the trans shop about the 4.3 trans is it a 700R4? or a 4L60 E

you might need to get the shift points adjusted for the 350

man i wish i still had my S15 with a small block
i still have the trans and a brand new 350 waiting for a body to drop it in

as for the engine i would get the block hot tanked and checked at the machine shop BEFORE purchasing any parts.
then go from there
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Old 03-19-2008, 09:01 PM   #9
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i was going to have the block cleaned and checked for cracks. and i was leaning towards having them hone the cylinders too. just so i know it is done right.

any esitmation on how much the rebalance would be? and if i do that, would i even need new pistons?

i did keep the caps in order, and marked them. i dont know why i didnt mark the pistons/rods. i feel like such a jacka$$ for doing that. but what can i do now. live and learn.
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Old 03-19-2008, 09:02 PM   #10
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Quote:
Originally Posted by GMC Guy
double check at the trans shop about the 4.3 trans is it a 700R4? or a 4L60 E

you might need to get the shift points adjusted for the 350

man i wish i still had my S15 with a small block
i still have the trans and a brand new 350 waiting for a body to drop it in

as for the engine i would get the block hot tanked and checked at the machine shop BEFORE purchasing any parts.
then go from there
i am certain it is a 700r4. its an 89.
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