offset valve seats
Moderator: Team
offset valve seats
here is a picture of a Harley Davidson twin cam with offset valve seat. they work quite well
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Re: offset valve seats
Pictures of the cylinder head
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Re: offset valve seats
Machining offset seat
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Re: offset valve seats
Interesting application of an age old speed "secret" of moving valve center(s) and or angles to gain performance. It still works if the application is happy with the change.
First did it in 1961 on a Studebaker V8. It worked. Many happy years followed.
First did it in 1961 on a Studebaker V8. It worked. Many happy years followed.
Re: offset valve seats
I have done this many times, moved valve centerlines.
Why to the hd twin cam? Is it because of valve overlap?
Why to the hd twin cam? Is it because of valve overlap?
Re: offset valve seats
This is different. He just moved the throat. The seat and guide are located stock
Re: offset valve seats
Ok. This is a very common way to make a seat by hand porting after seat job. It takes a couple of minute to do that move.
Re: offset valve seats
Ok, for the stupid like me....How do you move a valve seat without moving the guide? You are talking lateral moves and not in or out ?
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: offset valve seats
I can see the valve seat is moved but don't understand what it accomplishes?? The valve has not moved
In relation to the port.
In relation to the port.
Re: offset valve seats
The throat or venturi is not round after offset portning. Short side radius is better after that move. I do this every time, for every head when porting.
Re: offset valve seats
Thanks I get the concept. It seems that it would add a lot of dollars to the porting job for 8 off set intake seats and
8 exhaust seats. What is the return on investment in terms of CFM and torque.
8 exhaust seats. What is the return on investment in terms of CFM and torque.
Re: offset valve seats
Good question, I would be more interested in hp and tq with a back to back test. Added flow does not always equal more of either