<VV> Engine building - bearing clearance

[Michael Kovacs]

I agree, the only fast and accurate way to check the clearances is to use plastigage. It can be done a couple of times if you want to be sure you are getting the accurate reading, but, mine always came up with the same measurement.
 MIKE KOVACS 



----- Original Message ----
From: "bobhelt at aol.com" <bobhelt at aol.com>
To: corvair at mts.net; virtualvairs at corvair.org
Sent: Thu, January 21, 2010 1:10:57 PM
Subject: Re: <VV> Engine building - bearing clearance


In a message dated 1/19/2010 9:07:36 P.M. US Mountain Standard Time,  
corvair at mts.net writes:

I put  the block together with .001 U/S bearings in it. I mic the bearing 
bore,  and I find I have .0006 clearance on #2 and #4, .0010 on #3, and 
.0016 on  #1. So I take it apart, and put standard bearings in #2 and #4. 
That  should give me .001 more clearance, because they are .001 larger, 
right? I  measure, and now I have .0025 clearance...

So are .001 U/S bearings  actually .001 U/S EACH, so that a pair of them 
take away .002 in  clearance?

Looks like what I need on #2 and #4 is a .001 on one side,  and a STD on 
the other, to give me .001 more total clearance....  correct?

Thanks,

Les



Hi Les,
You said you mic'd the bearings. Why not use the plastigage recommended in  
the shop manuals? Miking the bearings is difficult to do accurately. You 
can  mike the crank journals OK, but the bearings????  And miking the main  
bearing bores is also difficult to do accurately. They could be out of round  
too.
It's possible that you might get different readings due to different  
torque on the long bolts (nuts that is) or shifting of the case halves.
Regards,
Bob Helt