Phil.S Posted July 9, 2006 Posted July 9, 2006 Hello all I'm looking at buying a cylinder head for modding or one that has already been done. I've found a janspeed modified one and it says it has triple cut valves. What does this mean? Just though aswell, I'm going to put some fast road cams in it aswell. Is it worth fitting vernier pulleys or not - the overall plan is modified head, vvc inlet plenum, cams, bb exhaust manifold. What do you reckon? oh yeah I'm on a (tight) budget too!
simondann111s Posted July 9, 2006 Posted July 9, 2006 Hello all I'm looking at buying a cylinder head for modding or one that has already been done. I've found a janspeed modified one and it says it has triple cut valves. What does this mean? It may be the ginding process used to seat the valces into the head and get the best match. Done three times with progressively finer grinding paste. I could be talking utter bollox though, it's been a long time since I did vehicle engineering at college......
Martin_S Posted July 9, 2006 Posted July 9, 2006 Simondann is quite right...he's talking utter bollox! Triple cut valves (AKA 3-angle valve seats) are where the valve seats are machined at 3 progressively steeper angles. Difficult to describe, but this link should make it clearer: http://www.hanzenginehouse.com/HANZENGINEH...at_closeup.html Advantage is that it marginally improves flow past the valves as the engine breathes in and out. Disadvantages are that since the valve seats only on the narrow, middle band of the valve seat, valve sealing isn't so good, doesn't last as long and 3-angle valve seats are more prone to burning out exhaust valves.
simondann111s Posted July 10, 2006 Posted July 10, 2006 Simondann is quite right...he's talking utter bollox! Triple cut valves (AKA 3-angle valve seats) are where the valve seats are machined at 3 progressively steeper angles. Difficult to describe, but this link should make it clearer: http://www.hanzenginehouse.com/HANZENGINEH...at_closeup.html Advantage is that it marginally improves flow past the valves as the engine breathes in and out. Disadvantages are that since the valve seats only on the narrow, middle band of the valve seat, valve sealing isn't so good, doesn't last as long and 3-angle valve seats are more prone to burning out exhaust valves. But I was close, it was something to do with the valve seat
Steve J Posted July 10, 2006 Posted July 10, 2006 I thought they had to do it three times beacuse they messed it up the first two times.
Phil.S Posted July 10, 2006 Author Posted July 10, 2006 Simondann is quite right...he's talking utter bollox! Triple cut valves (AKA 3-angle valve seats) are where the valve seats are machined at 3 progressively steeper angles. Difficult to describe, but this link should make it clearer: http://www.hanzenginehouse.com/HANZENGINEH...at_closeup.html Advantage is that it marginally improves flow past the valves as the engine breathes in and out. Disadvantages are that since the valve seats only on the narrow, middle band of the valve seat, valve sealing isn't so good, doesn't last as long and 3-angle valve seats are more prone to burning out exhaust valves. Ah tis all clear now.
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