Recipe for Valve Float???
10-28-2008, 10:09 PM
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Recipe for Valve Float??? I am getting ready to stick my car on the dyno. My combo is as follows:
Comp Custom Grind X-ER Lobe
244/248 .620 lift 110*
Comp Shaftmount Rockers 1.7
Patriot Gold Dual Springs
Smith Brothers / Oil Restrictor Push Rods
Comp "R" Lifters
I have driven the car about 20 miles and have made some passes in it to about 6500 rpms, it doesnt seem to fall off. However, I am watching other things to notice a hole lot.
Anyhow, the reason I ask is i have a buddy that had everything else the same as my valvetrain except for the lifters. His setup had valve float terribly, they pulled the rockers and pushrods out off his engine, put standard push rods and stock rockers on it. Valve float is gone...
I think his lifters were morel(sp?) and supposedly my engine builder is telling me that the morels have a similar oil restriction in them like the pushrods did. He said that was redundant and was causing the float.
I really want to think that I am not going to have problems with mine. Any insight would be appreciated.
-Ryan
Comp Custom Grind X-ER Lobe
244/248 .620 lift 110*
Comp Shaftmount Rockers 1.7
Patriot Gold Dual Springs
Smith Brothers / Oil Restrictor Push Rods
Comp "R" Lifters
I have driven the car about 20 miles and have made some passes in it to about 6500 rpms, it doesnt seem to fall off. However, I am watching other things to notice a hole lot.
Anyhow, the reason I ask is i have a buddy that had everything else the same as my valvetrain except for the lifters. His setup had valve float terribly, they pulled the rockers and pushrods out off his engine, put standard push rods and stock rockers on it. Valve float is gone...
I think his lifters were morel(sp?) and supposedly my engine builder is telling me that the morels have a similar oil restriction in them like the pushrods did. He said that was redundant and was causing the float.
I really want to think that I am not going to have problems with mine. Any insight would be appreciated.
-Ryan
Last edited by Formulized94; 12-09-2008 at 09:25 AM.
12-08-2008, 09:51 PM
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Showed it *** on the dyno today. It would not rev past about 4500 rpms...PISSED!
I am worried about putting stock rockers back on it and the port ceilings pulling off of the head.
I am worried about putting stock rockers back on it and the port ceilings pulling off of the head.
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12-09-2008, 04:55 AM
#9
A shim of 0.005 will only increase seat/open force by 1.8 lbs, are you sure of the shimming? Shims typically come in 0.015, 0.030 and 0.060 thicknesses. What is the installed height?
The Comp shaft rockers also have some geometry issues, have you considered a different rocker like the Yella Terra? Were the Comps set up with the correct geometry? Your lifters require a very very small preload, from memory it is 0.002"-0.004" and Comp requires an adjustable valve train for them. The Morels are not oil restricted, they are longer and specifically designed for an aftermarket cam that places the lifter lower in the bore so it is oiled correctly.
Last edited by vettenuts; 12-09-2008 at 05:02 AM.
12-09-2008, 05:10 AM
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So how much pressure do you need to run aftermarket roller rockers? I was thinking of doing this in the interest of quieting down my valve train. I figured Id be good with the PRC dual springs, like 390 open I believe.
12-09-2008, 09:16 AM
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As I was afraid, you don't have enough valve spring. Either lighten things up (rockers/springs) or get stiffer dual springs. AFR 8019's "might" work or check with PAC, they recently introduces some stouter duals.
A shim of 0.005 will only increase seat/open force by 1.8 lbs, are you sure of the shimming? Shims typically come in 0.015, 0.030 and 0.060 thicknesses. What is the installed height?
The Comp shaft rockers also have some geometry issues, have you considered a different rocker like the Yella Terra? Were the Comps set up with the correct geometry? Your lifters require a very very small preload, from memory it is 0.002"-0.004" and Comp requires an adjustable valve train for them. The Morels are not oil restricted, they are longer and specifically designed for an aftermarket cam that places the lifter lower in the bore so it is oiled correctly.
A shim of 0.005 will only increase seat/open force by 1.8 lbs, are you sure of the shimming? Shims typically come in 0.015, 0.030 and 0.060 thicknesses. What is the installed height?
The Comp shaft rockers also have some geometry issues, have you considered a different rocker like the Yella Terra? Were the Comps set up with the correct geometry? Your lifters require a very very small preload, from memory it is 0.002"-0.004" and Comp requires an adjustable valve train for them. The Morels are not oil restricted, they are longer and specifically designed for an aftermarket cam that places the lifter lower in the bore so it is oiled correctly.
The main reason for using these rockers was to help to keep the integrity of the port ceilings. I am afraid if I go back with stock rockers that the ports will pull out.
12-09-2008, 12:22 PM
#12
Well since you now need more spring, the forces even with the shaft system will go up and so will loading to the head. What heads are they?
One other consideration, Lingenfelter makes a steel rocker support for stock rockers that may help reduce local loads to the head. Call them and talk to them about your concerns. Jason Haines is a good guy to talk with.
One other consideration, Lingenfelter makes a steel rocker support for stock rockers that may help reduce local loads to the head. Call them and talk to them about your concerns. Jason Haines is a good guy to talk with.
12-09-2008, 01:36 PM
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Well since you now need more spring, the forces even with the shaft system will go up and so will loading to the head. What heads are they?
One other consideration, Lingenfelter makes a steel rocker support for stock rockers that may help reduce local loads to the head. Call them and talk to them about your concerns. Jason Haines is a good guy to talk with.
One other consideration, Lingenfelter makes a steel rocker support for stock rockers that may help reduce local loads to the head. Call them and talk to them about your concerns. Jason Haines is a good guy to talk with.
I appreciate the info on the lingenfelter rocker supports
12-09-2008, 07:20 PM
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Well we went over the valve train tonight and two cylinders were miss adjusted. The car pulls out standing until about 6100-6200 rpms. It does not matter how you get it to that rpm.....rolling into the throttle or hammering on it it falls on its face hard. I had the guy with me that built the engine and he says it was for sure valve float...of course...
12-10-2008, 02:49 AM
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12-10-2008, 04:52 AM
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I just did AFR heads with the 8019 valve springs. I was told ahead of time that the Yella Terra rockers and the AFR base valve springs might run into float issues, hence the upgrade. No float with the 8019 valve springs.
12-10-2008, 07:37 AM
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I recently looked at some LS3 heads chuck did that are amazing. A buddy of mine welds up the heads so chuck can reshape the runners. They are a work of art for sure.