[DeTomaso] Bronze or Steel Valve Guides

[JDeRyke at aol.com]

In a message dated 7/18/10 2:48:02 PM, tborcich at msn.com writes:

> The exhaust guides were already done (not my original heads) with steel 
> and I'm not sure if they should be redone.
> 
Its pretty easy to tell if a guide is badly worn. You take a valve and 
stick it in upside-down- from the rocker side. With a couple of inches of valve 
stem in the top of a guide, if you can wobble it more than maybe 1/16", it 
too worn to center a valve grinder mandrel- or a valve. Bronze guides are no 
harder to correctly clearance than other materials, but bronze does take 
different clearances than cast iron, and chromed valvestems take different 
clearances than 'regular valve stems, too. If a shop uses bronze-clearances for 
cast iron guides, (or vice-versa) you'll have trouble. My used Ford/SVO 
aluminum heads were built with bronze guides in 1984; when I bought them from an 
ex-drag racer, I also bought an extra set of bronze guides. Which I still 
haven't needed... Good luck- J Deryke