<VV> Re: polishing cranx

[djtcz at comcast.net]

Should have added that the swarf from crank polishing goes right into the crank's oil holes, where it will lie in wait for an opportunity to go straight to the rod bearings.  Solvent and air are not sufficient to clean those holes. Scrubbing strokes from Gun cleaning brushes almost alway extract satisfying amounts of crap.
--
Dan Timberlake

-------------- Original message -------------- 
Message: 10
Date: Sun, 18 Jun 2006 16:57:54 +0000
From: djtcz at comcast.net
Subject: <VV> Re: crank polishing
To: virtualvairs at corvair.org
Message-ID:
	
<061820061657.28449.4495861200036FE500006F212200734830960C9B060B 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