PVC.. Better with advancing the cam?
- Thread starter birel21y
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NXcoupe
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Why run 1.7's? that's where your ptvc would become an issue. yes, advancing the cam can help with it, depending on the event timing of the camshaft. I know that excessively retarding the cam timing causes the exhaust valve to connect with the piston in higher rpm's.
Well, i already bought an adjustable double roller cam gears/ chain. Where should i run this E303 cam? I understand that advancing= lower rpm power curve, and retarding= Higher RPM power curve. Has anyone experimented with this with an E303 cam? Thanks.
Also, i bought this spring kit. Do you think the OEM push rods will be strong enough? Trick flow told me this kit will handle up to 540 lift. Spring pressure is 110 @1.8, per Trick flow.
http://www.summitracing.com/parts/TFS-2500100/
http://www.summitracing.com/parts/TFS-2500100/
modo
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94GTcobra said:
size is one thing, valve timing events in relation to crank position is a totally different game. advancing / retarding a cam has a drastic affect on piston to valve clearance. there is no guessing and don't take someones word for it. either clay it or use a dial indicator.
I don't know the difference in the pistons on the stock 94-95 and the 92 down. I know the 92 down come stock with forged pistons and the 93 up don't. I have run the F303 and 1.7rr's on a stock bottom end 89 5.0 and a 91 5.0. So I don't see why you can't do it with a smaller cam on stock pistons in the 94-95 5.0.
NXcoupe
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I said what I said in the first post because he has stock heads and the stock springs and retainers don't have much forgiveness in them. If you over rev it, the retainer can hit the top of the valvestem. Add to that the fact that stock heads stop flowing at .450 or so lift and you have to ask yourself, why do it? Why up the lift on an already high lift cam for those heads?
When someone asks a question, I give them an answer, I may not have the time to go into every detail and every bit of experience that goes behind that bit of advice. Suffice to say, most cars that have an E cam in them with stock everything else usually don't make much if any more power at all over stock. It goes back to the heads and intake again. I have also spent a lot of time one year researching stock head porting and flowbench results. I published this in a forum that no longer eixists. I took stock heads, stock valves, cleaned the heads and the valves, and flowed them. I posted that flowsheet. Then I did a 'gasket match' to see what matching the intake and exhaust ports to a gasket and removing the bump in the top of the E7 head. Well to my suprise, it lowered the flow numbers. I don't mean a lot, but by 5 to 6 cfm. Same head, same port that I had previously flowed, same valves, etc. It flat did not improve it. So why did I then spend so much time on my heads? Well because when I started designing my own port, not going with what others had done, and just stabbing at it and trying this and trying that, because lets face it just about everyone has a bunch of these lying around and I was one of them. So I kept trying and failing to get good numbers until I threw it all out the window and tried something, and it worked. I was able to get huge numbers out of the exhaust and pretty good out of the intake, to the tune of nearly 80 cfm on the exhaust and not quite as much on the intake. I had to use stainless 1.9 intakes and 1.6 exhaust. It made one hell of a nitrous head, to the tune of a 10.0 with a stock cam and TFS street heat intake. I still have these heads, and they are going onto another project down the road sometime. Believe me I got a lot of grief from people running these heads, but you can't argue with the results.
But back the OP. Increasing the lift on my flow testing above .450 actually killed flow and became turbulent. I can't remember the exact lift number, but I think it was nearing the .480 mark or so. I do remember thinking how brilliant the ford engineers were designing a head that reached it's peak flow near the range of their stock camshafts.
So anyway, that's what I meant, since he is running the TFS spring kit, there are no worries then, lift away!
When someone asks a question, I give them an answer, I may not have the time to go into every detail and every bit of experience that goes behind that bit of advice. Suffice to say, most cars that have an E cam in them with stock everything else usually don't make much if any more power at all over stock. It goes back to the heads and intake again. I have also spent a lot of time one year researching stock head porting and flowbench results. I published this in a forum that no longer eixists. I took stock heads, stock valves, cleaned the heads and the valves, and flowed them. I posted that flowsheet. Then I did a 'gasket match' to see what matching the intake and exhaust ports to a gasket and removing the bump in the top of the E7 head. Well to my suprise, it lowered the flow numbers. I don't mean a lot, but by 5 to 6 cfm. Same head, same port that I had previously flowed, same valves, etc. It flat did not improve it. So why did I then spend so much time on my heads? Well because when I started designing my own port, not going with what others had done, and just stabbing at it and trying this and trying that, because lets face it just about everyone has a bunch of these lying around and I was one of them. So I kept trying and failing to get good numbers until I threw it all out the window and tried something, and it worked. I was able to get huge numbers out of the exhaust and pretty good out of the intake, to the tune of nearly 80 cfm on the exhaust and not quite as much on the intake. I had to use stainless 1.9 intakes and 1.6 exhaust. It made one hell of a nitrous head, to the tune of a 10.0 with a stock cam and TFS street heat intake. I still have these heads, and they are going onto another project down the road sometime. Believe me I got a lot of grief from people running these heads, but you can't argue with the results.
But back the OP. Increasing the lift on my flow testing above .450 actually killed flow and became turbulent. I can't remember the exact lift number, but I think it was nearing the .480 mark or so. I do remember thinking how brilliant the ford engineers were designing a head that reached it's peak flow near the range of their stock camshafts.
So anyway, that's what I meant, since he is running the TFS spring kit, there are no worries then, lift away!
