Do I need headwork for new valves?

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Jun 2, 2005 | 11:06 AM
  #1  
I'm replacing all of my valves and I'd like to know if I need to replace the guides also.

ITR head with a burnt valve. 36k on the clock.
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Jun 2, 2005 | 11:17 AM
  #2  
Re: Do I need headwork for new valves? (D50boy)
Using one of the new valves, extend the valve 10mm from the seat and measure the guide-to-stem clearance with a dial indicator. (using the wobble method)

Clearances should be as follows:

For intake: 0.002" - 0.006"
for exhaust: 0.004" - 0.009"

Also check for smooth movement of the valve as you push it up and down the guide. (rotate the valve back and forth between finger and thumb as you do this)

Hope this helps
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Jun 2, 2005 | 12:01 PM
  #3  
Re: Do I need headwork for new valves? (jmcclell)
so.... if it doesnt wobble much at all, dont mess with it?
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Jun 2, 2005 | 12:23 PM
  #4  
Re: Do I need headwork for new valves? (D50boy)
Yes, to put it more simply

You will have to get the valves lapped into the seats tho.
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Jun 2, 2005 | 12:27 PM
  #5  
Re: Do I need headwork for new valves? (jmcclell)
You mean a "3-angle valve job"?


I'm fairly new to doing it the right way.
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Jun 2, 2005 | 02:39 PM
  #6  
Re: Do I need headwork for new valves? (D50boy)
Each valve has to be "lapped" to its corresponding valve seat, to give a tight seal.
An abrasive cutting paste and a special tool with a plunger on the end, to grip the valve face is used to "match" the valve to its seat.

Do a google search on "valve" and "lapping", to give you a better idea.
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