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Bad bug
June 22nd 2003, 12:26
What are the larges size valves that can be placed in a 96mm bore cylinder head.
Tony Z
June 22nd 2003, 14:20
I think 46x40 would be getting towards the limit. I personally wouldnt go above 44x38 in that bore size
Bad bug
June 22nd 2003, 21:12
is their a reason for not going 46x40, does it weaken the head.
vujade
June 23rd 2003, 08:21
I think he was saying that is wasnt wise to go above 46 x 40 if you are going to use 96mm pistons.

If you are using big bore pistons (102mm - 105mm) then I have heard of people using 50 x 40 valves in a T4 head.
Tony Z
June 23rd 2003, 16:03
A lot of people just put in bigger valves because they flow more air. Ever heard of someone "unshrouding" a valve? This means you move the wall away from the valve to allow the side nearest the wall to flow properly. If you go too big on valve sizes, you actuall put a lot of the valve along and very close to a wall and thereby actually reduce the airflow of the head simply because 30% or so of the valve is not being used porperly or at all.