BEARING & PISTON CLEARENCE`S

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SLICK VIC
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BEARING & PISTON CLEARENCE`S

Postby SLICK VIC » Sun Feb 25, 2007 1:38 pm

WAS WONDERING WHAT KIND OF.clearence`s..
on a BBC... blown alky/nitro 6-71 STD
magIII 30-35 LBS BOOST
steel crank,..steel block,...aluminum rods, forged pistons

main bearing clearence ? oil
rod bearing " " oil
piston to cylinder wall
rod side clearence

thanks
Vic
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SMOLDERY SMOKEY BURNOUTS TO YOU ALL

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Rapid Randy Baker
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Postby Rapid Randy Baker » Sun Feb 25, 2007 10:28 pm

Vic, I would have to check back in my notes. If I remember correctly the cyl walls to piston are around 26-28 thou.

You want all the clearances a little looser with the Nitro in the mix.
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Solid Rock
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Postby Solid Rock » Sun Feb 25, 2007 10:30 pm

Rapid, That sounds like an aweful lot of clearance to me.

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SLICK VIC
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Postby SLICK VIC » Sun Feb 25, 2007 10:42 pm

i agree solid,..maybe more like .006-.008 ???
on the piston wall ??
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Solid Rock
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Postby Solid Rock » Mon Feb 26, 2007 8:48 am

That's what I'm thinking Vic. I'll check my records later today on what I have and post them.
I can't see getting any ring seal with .026 piston to wall clearance. The piston will be rocking in the bore too much to seal.

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Rapid Randy Baker
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Postby Rapid Randy Baker » Mon Feb 26, 2007 9:32 am

Good thing we don't build engines from my memory,,,I have it in my notes, but it is in the race book at home. I know I checked it when we were having some Piston scuffing way back with the BBC. Now you have me wondering and will have to look at my notes! :roll:

Plus,,,I am on meds for this cold so I do have an out!! :wink:
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Leon
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Postby Leon » Mon Feb 26, 2007 1:46 pm

p/w=usually .008 depends on the manufacturer

main=.004

rod= .003-.0035

side=.045-.060 depends on the manufacturer

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Rapid Randy Baker
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Postby Rapid Randy Baker » Mon Feb 26, 2007 9:03 pm

You are right Wheelz! :lol:

With no great suprise, Leon is right. My numbers match his range, except my notes say piston to cyl wall: 8 was normal, with nitro 10-12, and we ran 11 on ours. :wink:

I am blaming it on the cold medicine!! :wink: :roll: :lol: :lol:
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SLICK VIC
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Postby SLICK VIC » Mon Feb 26, 2007 10:18 pm

DAY TIME THERA FLU,..NOT NITE TIME NYQUIL...

THANKS GUYS I GOT A GOOD IDEA NOW.

VIC
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SMOLDERY SMOKEY BURNOUTS TO YOU ALL


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