<VV> Re: crank polishing

[djtcz at comcast.net]

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For years the "Chevy Power" books from GM contained a polishing procedure using strips of 400 grit (wet-or-dry?) sandpaper shoelaces and a shoe shine motion.  Bill Jenkin's Chevy engine book contains good advice about polishing Tufftrided cranks

I worked in a shop that did high performance engine work for several years.
We hand polished cranks, etc in a lathe until we got one of those powered belt polishers  like this one. http://www.goodson.com/technical_support/instructions/PCP-1070.pdf
With a fresh belt a tenth or 2 of taper (the limit for good quality work) could be pumped into a journal in no time.  I never used that polisher again.  I would not polish a crank without using a micrometer before, during, and after.

I would not hesitate to use strips of 400 grit or finer paper, pre-dulled by dragging over a clean steel surface (vice anvil, etc).  Directional polishing is important, especially on Tufftrided/nitrided cranks.  Literature states improper polishing direction can tear bearings down to the copper.

--
Dan Timberlake

-------------- Original message -------------- 

> Date: Fri, 16 Jun 2006 11:55:34 -0500 
> From: Stephen Upham 
> Subject: Polishing bearing journals 
> To: virtualvairs at corvair.org 
> Message-ID: 
> Content-Type: text/plain; charset=US-ASCII; format=flowed 
> 
> I need a quick answer. I remember the man I bought the crank from 
> polishing the surface of the bearing journals with a fine grit 
> sandpaper in order to polish them. What #grit would be appropriate for 
> that. 
> 
> Stephen U 
> 
> 
>