WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
01-05-2007, 09:52 PM
#1
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WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
I am converting to MAF and I feel like I want to put a cam to help complement my ported intake and heads. My question is what cam specs should I look for? I have stock heads, ported out and decked .030 running 1.7 roller rockers(thinking my PTV clearance is about .060 less). I think I have limited myself by decking the heads and running the 1.7's, but I figure there are others running something simular. Any advice would help.
01-05-2007, 10:14 PM
#3
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RE: WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
I have new .600 lift springs when I ported my heads. I want to know what duration I can run with about a .500 lift cam to clear my pistons.
01-05-2007, 11:17 PM
#5
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RE: WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
You can run a .550 lift cam with stock pistons.
I used to run GT40P heads that were shaved 0.040" and 1.7 rockers with a Ford F cam and it had plenty of PTV clearence. It has 288/288 Duration & 544 lift with 1.7s
I used to run GT40P heads that were shaved 0.040" and 1.7 rockers with a Ford F cam and it had plenty of PTV clearence. It has 288/288 Duration & 544 lift with 1.7s
01-06-2007, 02:28 AM
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RE: WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
Isn't duration the limiting factor when it comes to PTV clearances? Correct me if I am wrong, but technically, I could run a .600 lift cam if it had a short enought duration.
I just want to know what is better, the lift of the E cam or the duration of the B cam. Thanks tho
I just want to know what is better, the lift of the E cam or the duration of the B cam. Thanks tho
01-06-2007, 04:00 AM
#9
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RE: WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
Lift and duration affect PTV clearance, but duration more so. I ran my E cam w/ 1.72's (.535 lift) w/o any issues, but I would recommend claying up anything close to .530.
The B cam w/ 1.7's is supposed to be a great combo, but your power will be down lower, as opposed to the E cam which will put it up higher in the rpm band. I like the TFS stage 1, but I don't know that I'd risk running it w/ 1.7's......
The B cam w/ 1.7's is supposed to be a great combo, but your power will be down lower, as opposed to the E cam which will put it up higher in the rpm band. I like the TFS stage 1, but I don't know that I'd risk running it w/ 1.7's......
01-06-2007, 11:19 AM
#10
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RE: WHAT CAM CAN I USE WITHOUT SMASHING MY VALVES??
It's not duration and lift....it's the overlap "phase" (exhaust to intake cycle change) when both intake and exhaust valves are open anywhere from .016" to .157" (lift) at the same time, and the piston at TDC.....or when they are like.....
Lift alone is not a problem since max lift occurs when the piston is >1.5" down the bore, no way it could hit the valves. A lot of factors come into play for a PtV clearance problem to be present.....duration, lobe separation angle, cam timing, heads, valves position, quench, valves size vs. piston valve relieves, etc......check the article at http://www.fordmuscle.com/fundamentals/pistontovalve/
Lift alone is not a problem since max lift occurs when the piston is >1.5" down the bore, no way it could hit the valves. A lot of factors come into play for a PtV clearance problem to be present.....duration, lobe separation angle, cam timing, heads, valves position, quench, valves size vs. piston valve relieves, etc......check the article at http://www.fordmuscle.com/fundamentals/pistontovalve/