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View Full Version : whats the benefit of a big valve head?


bigjim
13-11-2005, 22:40
pm'd benr about head work and cams and he mentioned bigger valves? whats the benefit of running bigger valves over standard? is it because the head is ported more so requires bigger valves and thus gets more flow than standard? is it worthwhile?
BenR
13-11-2005, 23:25
lol, why didnt you ask?

Basically the more valve area you have, the more scope for flow you have, the more flow you can produce, the more power and torque you can make on any given cam profile. Increased efficiency if you will.

Even the largest of my custom 35mm inlets is bump up the head in the world of high performance 16V heads. The F7 engine doesnt have scope for alot of valve area.

The Mi16 has 34.6mm inlet std, the F4R 33.5mm, S2000 35mm and new duratec 35mm.
richy
13-11-2005, 23:28
ben would running 33mm valves be benifical or better off with 35mm valves on a flower/ported head for F7R?
BenR
14-11-2005, 01:06
33mm is beneficial over std willy valves, so long as appropriate porting is done otherwise they will flow less than std, hence the bowlport level of work.

35mm's is a ultimate, but they are heavier and require stronger springs and lightweight retainers if your going to rev them high. BUt they do flow, and flow well. They are nowhere near as cheap though as you need the valve seats replaced with larger inserts and extensive porting.
VIPERONE
14-11-2005, 01:12
theres a company in newcastle that convert valver heads to run 35mm valves for £300... i'll dig out the link
BenR
14-11-2005, 01:16
good price, what valves do they run?
VIPERONE
14-11-2005, 01:18
i havent got a clue, i once saw one of their head on ebay for buy it now, im sure it was 35mm, i can remember think hmmm surely not.

i know stan is running shims to make up the length in his valves....
BenR
14-11-2005, 03:02
erm, flow passage control?

Yea, stans got to use those, but since i have to offer customers a once stop straight installation, i had them made.
neilc
14-11-2005, 10:32
theres a company in newcastle that convert valver heads to run 35mm valves for £300... i'll dig out the link

Could be an excuse to get my valve steam oil seals replaced :D
richy
14-11-2005, 12:10
benr pm'd u :)