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Does anyone use a set of these heads? I have a set and the guides are bad after very little run time. The problem with having Dart replace them is they are 4-5 years old. They have less than 2 hours of run time on them.

How tight should the guides fit around the valves? I have a lot of side play and believe it is to much.
 

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Martin,

The clearance should be about .001 stem to guide. Maybe around another .0005 on the exhaust side for heat. In other words, it should fit not much differently than a piston/pin assembly.... should be relatively slop free if you don't have a gauge.

If you can't measure it you'll just have to use your best judgement. Put a valve in the guide, and see if you can side load the valve at the head, with the top of the stem, and see how it interacts with the seat. If it's scrubbing the seat on one side pretty hard then the guides are out of spec.
 

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Discussion Starter #3
I talked to Dart this morning and they are shipping me some replacement valve guides free of charge. It seems they are I different OD then most and only a few companies carry them.

I finally found something on this motor that didn't cost me anything.
 

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The problem with that Martin is that the heads will need a new valve job after you put the new guides in. Not really a problem, just be aware.
 

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After installing the guides, they need to be either broached or reamed then finish honed. Then the valve job. Alot of work to be done, impossible if tooling is not available. .... 8)


Rich Maitre
RAM Racing Heads
www.ramracing.us
 
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