Minimum LS3 main bearing clearance?

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Dec 10, 2016 | 11:10 AM

Senna

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From: San Jose CA

Minimum LS3 main bearing clearance?

I'm fitting bearings in my LS3 build, new GM block and new GM crank.Using Clevite 77P bearings. Measured with Mic and dial bore gauge.

I've got .0014"-.0016". If this was a cast block there would be no question that this would be to tight. But being as this is aluminium and will loosen up at operating temp and the factory minimum is .0008" I think I'm good to go.

What's the feeling on one and a half thousands main bearing clearance?

Dec 10, 2016 | 04:57 PM

KCS

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Need more info. What's the engine being used for? Street/strip, drag race, endurance racing? NA or power adders?

Dec 10, 2016 | 05:41 PM

Senna

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Quote:

Originally Posted by KCS

Need more info. What's the engine being used for? Street/strip, drag race, endurance racing? NA or power adders?

Ok,

Basically a NA street engine in a 66 Chevelle, Tremec 6 speed and 373 gears for spirited driving and maybe an ocational autocross.

Like I said, stock block and crank with Scat H beam rods and Wiseco forged pistons. BTR stage II cam. 10.7 Comp ratio

Probably wouldn't be ran as hard as some people run a crate engine with a cam change.

I just finished the rod bearing clearance and they are at .0023"-.0024".

Dec 11, 2016 | 09:38 AM

KCS

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It should run fine the way it is. I'd have to look but I don't think there's much you can do with a P series bearing anyways in terms of undersized of X bearings.

Dec 11, 2016 | 10:26 AM

Senna

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Quote:

Originally Posted by KCS

It should run fine the way it is. I'd have to look but I don't think there's much you can do with a P series bearing anyways in terms of undersized of X bearings.

Right, no + or - in P bearings. I was looking at other brand bearings and King was mention a couple time for having .0005" more clearance, but, compared to what.

I'm not sure yet that I am comfortable with it or not. If another brand bearing was known to have more clearance I would give it a try.

I don't know if it unrealistic to think the crank could be polished .0005? This is really where the problem stems from. The crank is 2-3 tenths over the high limit.

Dec 11, 2016 | 11:22 AM

pantera_efi

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Powdered Iron Mains/Al Block

Your AL block will "grow" to .002" when up to temp with observed measurement.
You will have great oil pressure with a 2010 Camaro Oil Pump (a $90.00 OEM pump "shimmed")
This as stated above will be fine for your use.

I would be more concerned with the Rod Clearance ?

I have assembled Ford Boss 429 (494 Can Am) engines with BOTH AL block and caps (FORD OEM).

That case we required NO GREATER than .001" at "room"

Lance