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Is Beef correct??

  • Yes, Beef is right

    Votes: 2 66.7%
  • No, Beef is wrong

    Votes: 1 33.3%
  • Whats a valve job?

    Votes: 0 0.0%

  • Total voters
    3
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Discussion Starter #1
This is a calification for another member... and all I need is pretty much a confirmation that this is correct(even though I know it is).

When doing a 3 angle(or any angle for that matter) valve job the 3(or 5 or whatever) angle cuts are cut into the valve seat in the head and the valve only recieves one cut commonly refered to as the interference angle or "facing the valve" and this also sets the valve margin.


Thanks
 

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They call it a valve job for a reason. The valve seat only seats to one angle on the valve. Now the valve seats might have to be swapped to match the new-ground angles on the valve, but its the valve that is actually ground.


Thank you, drive through
 

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Discussion Starter #3 (Edited)
I see we have 2 people who dont know how to do a VALVE job now...

The VALVE SEAT IN THE CYLINDER HEAD(read: NOT VALVE) gets the multi angle cut, NOT THE VALVE ITSELF. The reason for cutting the SEAT with multiple angles is to provide the incoming air a smoother transition from the port past the valve and into the cylinder.


going back through the drivethrough because the order was
wrong


Edit: The valve can technically get more than one angle cut, but as explained above is the basis for a "valve job"
 

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Like I said, the valve seats might need to be replaced/modified to fit the valves, but the valves DO get ground in some cases.

Maybe not all the time, but there are multi angle valves out there.

Edit: This page proves my point, scroll down about halfway, there's a pic of a valve grinder with a little comment. http://www.performanceaeroengines.com/tour.htm
 

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So we're both right in a way.

Discussion over :)
 

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The typical 3 angle valve job is a 45* angle on the seat with a 30* top cut and a 60* throating cut. One of the main reasons to do a 3 angle valve job is to properly position the valve face on the seat and provide the correct seating width. Seating width will vary depending on whether it is intake or exhaust and the particualr application, street, drag, OT, etc. The added benefit of the three angle valve job is smoother transition from port to combustion chamber. A valve job may even be 5 angle, with an additional 15* top cut and a 75* throating cut. You can also put a 30* backcut on the valve to smooth the flow across the valve face. Some people will refer to this as a 5 angle valve job.

An interference angle is something totally different. If you grind the valve seat at 45* a typical interference angle of 1* would require the valve face to be ground at 44* instead of 45*.

I just had to post this to prevent too much mis-information from being disseminated.
 
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