<VV> Engine building - bearing clearance

[corvair at mts.net]

Thanks Bob

That's what I'm finding - I can measure the journals three times and get within a tenth each time... measuring the bearing bores with my crappy chinese snap gauges it's hard to get within three tenths.

I used the mike because I live out of town, moved recently, and could find my micrometer and snap gauges but I couldn't find my plastigauge! Now that I have the right combination of bearing shells I will plastigauge it as a final check.

Am I correct that a .001 US bearing is supposed to take away .001 clearance for EACH bearing shell (.002 total if you use one on each side)? That's what my measuring looks like.

I have a nice .0010-.0016 across all four bearings now, all .001 except for 1 side STD in #2 and 1 side STD in #4.

Les
> 
> From: bobhelt at aol.com
> Date: 2010/01/21 Thu PM 12:10:57 CST
> To: corvair at mts.net,  virtualvairs at corvair.org
> 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
> 
>