<VV> Rod Bearing Clearance Question

[Bob Gilbert]

Thanks Mark and everybody else who responded!

Somehow  I missed the tolerances in the manual when I looked and I've got a
lot of feedback that indicates .002 clearance is fine.
Yes, the crank was micro-polished.

Regards,
Bob


-----Original Message-----
From: Mark Durham [mailto:62vair at gmail.com] 
Sent: February-07-12 5:31 PM
To: Bob Gilbert; virtualvairs at corvair.org
Cc: corvairs at cybrus.net
Subject: RE: <VV> Rod Bearing Clearance Question

Bob, my overhaul manual says .001 to .002 is the correct range for rod
bearings. You can go up to .003 with worn bearings, so .002 is good. I
assume the crank has been micro polished and sized to get the .002 reading,
correct?
If you are concerned, there are undersized bearings to take it that .001
closer. my journals varied a bit after micro polish. My readings were .001,
.0012, .0015, .0017, .0014 and .0015. Mark Durham

Sent from my Windows Phone
From: Bob Gilbert
Sent: 2/7/2012 16:42
To: virtualvairs at corvair.org
Cc: corvairs at cybrus.net
Subject: <VV> Rod Bearing Clearance Question Hi,



I've just started my 190 ci (3.l) build for my UltraVan and I'm using Bob
Helt's book plus the shop manual as my primary guides. Its' been 20 years
since I have done a complete engine like this so I'm using the books a lot!



The crankshaft was checked by both myself and a machinist we both found all
of the journals to be in spec and he recommended that all it needed was a
micro-polish.



I plastigauged the mains and the clearances were between the .0015 as per
Bob's book and .020. That was with standard size bearings.



However, I'm showing .002 clearance on the rod bearings. Bob says that .001
is ideal but I can't find anything to say whether .002 is enough to cause me
concern.



BTW, these measurements are being taken at about 40F. Is that enough to
cause the journals to shrink by .001?



Any thoughts or recommendations?



Regards,

Bob





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