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

 

I don't think you have enough valve spring for that setup. Fast ramp rates, high lift and heavier rockers. What are your seat and open spring values?

 

on the seat is around 150-155, I cant recall the open pressure.

 

it's around 365 I think?

 

Mine is closer to 390-395. The springs are shimmed .005

 

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.

 

That shouldn't be an issue running shaft mounts....

 

I know it is not going to happen with the shaft mounts. However, I am talking about putting the stock rocker on the engine. It has not been run with the stock rockers yet.

 

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.

 

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.

 

I apologize on the shimming error. It is actually .050 . I am positive of the shimming. I really hate that I did not put this engine together, because I cannot tell anything for sure with out asking the builder...


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.

 

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.

 

The heads are 853 castings.


I appreciate the info on the lingenfelter rocker supports

 

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...

 

It seems everyone running non-stock rockers runs into these valve float issues?

 

have a conferance call with comp and t and d setup in the am trying to figure this out

 

good luck with it. call me tomorrow and let me know what you figure out. tell chuck im very pleased with the throttle body.

 

Not if the entire setup is correct (valve springs have enough stiffness, proper geometry, etc.).

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.

 

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.

 

Chuck is a SAVAGE....j/k He does good work no doubt. Took him for a ride in the car lastnight and he seemed pretty impressed.