Too much clearance??

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hooter12
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Too much clearance??

Post by hooter12 »

Hi guys.

I'm building a small block chevy 383 stroker.
Just got block back from machining but I'm not satisfied with mains clearances.
I have measured both with micrometer and plastigauge.
Mains 1-4 seem to be ok, but 5th bearing is off.
According to micrometer, it's arround 0.0040"
But that is only of I measure top to bottom. If I measure at an angle (~45 degrees), than it's near 0.0030".

Ever had a situation like this? What would be a best thing to do?

This is bearing nr.1
Image

And this is nr. 5
Image
mag2555
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Re: Too much clearance??

Post by mag2555 »

It's a hard call to make as the rear main is also the thrust Bearing and as such it runs hotter then the other 4 bearings which means that being .0002" out might not be a cause for concern?

See what others say though!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
Newold1
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Re: Too much clearance??

Post by Newold1 »

Did you have the rear main seal in when you checked that clearance on #5 the rear main?? :wink:
The Older I Get, The Dumber I Get :wink:
hooter12
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Re: Too much clearance??

Post by hooter12 »

No, without the seal.

Here is pic when measured at approx. 45 degrees

Image
MotionMachine
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Re: Too much clearance??

Post by MotionMachine »

Micrometer says .004". I assume you mean that the rear main measures .0004" small, not .004"? If that's the case, then it's correct, the spec for the rear main o.d. is smaller than 1-4. If you really want to get picky, you should also torque the oil pump on the cap. If the shop line bored it, they would have done this when they machined it because the main bore will distort when the pump s installed.
hooter12
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Re: Too much clearance??

Post by hooter12 »

I wrote wrong, sorry.
The dial bore gauge says that clearance between crank (measured with micrometer and dial bore gauge zeroed to that measure) is 0.0040"
But that is measured top to bottom of the bearing. If I measure tilted 45 degrees, than it's 0.0030"

Plastigauge also shows the same.
zums
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Re: Too much clearance??

Post by zums »

Ive seen it plenty, what dose it measure in the other 45* direction, i wouldnt put it in print and it isnt textbook correct but it will still work, pump torqued as mentioned above, after market fasteners, same torque as when honed??, The vertical .004 is too much for my lioking
Tom
hooter12
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Re: Too much clearance??

Post by hooter12 »

Other 45 is also ok. Only vertical is off.
All new ARP hardware, cleaned threads....
I haven't tried with pump on. Will do that.
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