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fredmeister fredmeister is offline
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Join Date: Oct 2002
Location: Baltimore, MD, USA
Posts: 2,235
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clearance between valve guide and stem for OEM 930 wastegate

What is considered a normal clearance between the valve stem and the valve guide bore for an OEM 930 turbo wastegate?
I can here air blowing past the valve guide and into the exhaust port when I pressure test the wastegate housing. I realize a small amount of air will inevitably pass thru the clearance gap between the 2 parts, but when is it time to replace the valve guide from wear? I have not been able to find a spec on this yet. Would like this info in order to be able to machine a new guide and have it pressed into the housing if need be.

Air leaking past the guide is air lost to opening the wastegate valve so ideally this should be a minimum.

Appreciate any info,
Fred
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1979 930 Turbo....3.4L, 7.5to1 comp, SC cams, B&B intercooler, Snow Perf water/meth injection, Rarlyl8 headers, Garret GTX turbo, 36mm ported intakes, Innovate Auxbox/LM-1, custom Manually Adjustable wastegate housing (0.8-1.1bar),--running 0.7bar max
---"When you're racing it's life! Anything else either before or after, is just waiting"
Old 03-14-2013, 01:00 PM
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