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jwasbury jwasbury is offline
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Join Date: Jan 2008
Location: Weehawken, NJ
Posts: 3,593
Quote:
Originally Posted by zcoker View Post
This is a real issue that needs to be understood. It does make perfect sense. The guide only has a small middle portion that has the correct diameter when reamed, the rest of the guild becomes oversized, so the valve stems slap around and beat themselves out. The solution was to get undersized custom guides pressed in and then the the entire guide is reamed to spec. Cured! no problems, smooth as silk and runs better than ever.
Reading this thread made me nervous...with just 4k miles on my DIY rebuild.

I spoke with my machinist who confirmed this is a problem with the factory valve guides. I am happy to say that my heads were done with custom bronze-manganese guides that are reamed the full length to fit.

I sure hope it turns out to be nothing serious for you Jim (praying to the 930 gods)
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Jacob
Current: 1983 911 GT4 Race Car / 1999 Spec Miata / 2000 MB SL500 / 1998 MB E300TD / 1998 BMW R1100RT / 2016 KTM Duke 690
Past: 2009 997 Turbo Cab / 1979 930
Old 01-14-2011, 01:40 PM
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