 Main bearing clearances? |
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| stugray |
 Jul 28 2012, 08:56 PM
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Advanced Member  Group: Members Posts: 3,825 Joined: 17-September 09 From: Longmont, CO Member No.: 10,819 Region Association: None  |
I am getting ready to put my short block together and I have what appears to be a fairly new crank.
Main bearing journals: 2.361. The bearings appear to be new unused STD-STD. When I put on the main bearing that goes directly beneath the cam gear dry and wiggle it I get ~4 thousandths "wiggle" when measured with a dial indicator stuck to the flywheel. Does that sound correct? Would that be considered two thousandths bearing clearance (2 on each side = 4)? Stu |
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| nathansnathan |
Jul 29 2012, 10:45 AM
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Senior Member Group: Members Posts: 1,052 Joined: 31-May 10 From: Laguna Beach, CA Member No.: 11,782 Region Association: None |
The crank journal should be between 2.3610 and 2.3618. I've got some red and blue plastiguage here that measure 2 to 6 and 4 to 9 thousandths, respectively. Green is 1 to 3 thousandths. Is there a smaller color? - because the whole range of tolerance is +-4 ten thousandths, or 'four tens' as they say.
The other thing about measuring crank tolerances on the crank or the case is how true it runs, if it's whiplashed. You need a jig to check runout, a machine to check the concentricity of the crank bores in the case, if it needs align boring or not. |
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Posts in this topic
stugray Main bearing clearances? Jul 28 2012, 08:56 PM
mrbubblehead
I am getting ready to put my short block together... Jul 28 2012, 09:14 PM stugray Yes I have heard of plastigauge, but you cannot us... Jul 28 2012, 09:58 PM
mrbubblehead
Yes I have heard of plastigauge, but you cannot u... Jul 28 2012, 09:59 PM stugray Bump.
Bolting halves together today.
Anyone else ... Jul 29 2012, 10:08 AM McMark I've never measured the rock but it's defi... Jul 29 2012, 10:11 AM Racer Chris
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When I put on the main bearing that goes dire... Jul 29 2012, 10:32 AM stugray The crank is bolted to the flywheel sitting on the... Jul 29 2012, 11:03 AM nathansnathan I've always taken my crankcase, crank, and fly... Jul 29 2012, 12:18 PM stugray
No I am measuring how much the bearing moves sid... Jul 29 2012, 01:26 PM sixnotfour :beer2: Jul 29 2012, 02:50 PM ldsgeek The only way to check the clearance on those beari... Jul 29 2012, 07:07 PM |
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