rod bearings and checking the journals

[wc701lists at bellsouth.net]

At 08:14 AM 3/29/2007, David Pertuz wrote:
>granted that I can just replace the bearings with the same grades. 
>So I am assuming I will want to measure the journals.....but with 
>what? My memory of the amount of space involved tells me I can't fit 
>a mike in there. Is plastigauge any good under the circumstances? If 
>the journal surfaces look good am I likely to be OK with putting in 
>new bearings of the same grade?

The steps between bearing grades are like 4-ten-thousandths IIRC -- 
0.0004", like 1/4 of a sheet of paper  -- and the overall crank to 
bearing clearance is very tight in a new engine.  I don't think 
plastigauge works down to that clearance, or that it would be 
accurate to more than a thou' or so.

When I did one, I just cleaned it up with some < 1000 grit paper (it 
had smeared a bearing) and put in the same grades.  That should have 
opened up the clearances, but that's usually considered a good thing 
on an endurance racing engine.

>Also, are any of the old-timey folk here going to the convention this year?

Where's that?


    -Wayne  '06 RSX-S / 93 SE-R / 93 NK2k / 90 Miata / '07 Scion tC