Valvetrain gurus inside please.

[91CoupeMike]

So you guys believe its all in the lifters, and or the lash adjustment?

If I had that wrong it still would have made 320rwhp? I feel like that's damn good power and if the lash was wrong or the lifters were bottoming out, bent pushrods ect. wouldnt it would have been more noticeable throughout the curve, ect?

The valve train has noise but not a lot, it was loud at first.

I'm not arguing. I'm genuinly trying to understand as I've never had it broken down and explained in depth.

Thanks guys!

[91CoupeMike]

I know I need new lifters, swapping them out isn't an issue at all.

Would it be benifical to change springs, or the rocker arm ratio?

Realistically how much of a difference will .034 lift make?

[Samhain]

Mike, I might have missed it but what rockers? Stock?

[FoxBodyNick]

Mike, I might have missed it but what rockers? Stock?

Trick Flow

[Andy@PrimeTuning]

I'd leave it alone - fix your suspension and tune in some spray

That cam is pretty small - you aren't gonna see a lot of rpm

Also u can't get too wrapped up in a way a dyno graph reads

[91CoupeMike]

I'd leave it alone - fix your suspension and tune in some spray

That cam is pretty small - you aren't gonna see a lot of rpm

Also u can't get too wrapped up in a way a dyno graph reads

I'm not really worried about track times, I feel like the car runs great. It doesn't feel like it falls off at the top but I don't go over 6,000 anyways.

[racrguy]

I'm not really worried about track times, I feel like the car runs great. It doesn't feel like it falls off at the top but I don't go over 6,000 anyways.

Good, because it's all done at ~5800.

[greenbullitt]

I'd leave it alone - fix your suspension and tune in some spray

That cam is pretty small - you aren't gonna see a lot of rpm

Also u can't get too wrapped up in a way a dyno graph reads

yup

[zemog]

if you can put up with the oil and smoke with the motor running, you don't even need a gauge, just a ear, back off till it clicks, tighten it till it stops and another 1/8th. Even easier than solids.

man, that post brought back memories from the 80's LOL, did this quite a few times !!

[David L. Gary]

What he said

learn how to adjust lifters and your problem may go away.
when you adjust lifters like that your losing so much it's unreal.
Using a good set of used hyd roller lifters is no problem.

Crank each rocker arm over till the valve is fully closed, then barely bump it a tiny bit more, this assures the lifter is on the lowest part of the cam. Back the nut off till the pushrod has slack in it at the rocker arm. Screw the nut down till all the slack is out of the pushrod, turn it 1/8 turn more and lock it with the setscrew. do this on all 16 one at a time. I do this with the intake off so I can actually see the lifter top and see it deflect so I know when it's correct. This is on a race car and I don't care if there is a small amount of lifter click. The way you have it now, the lifters are not letting the valves fully close at upper rpm range. With it adjusted the way I do it the lifter can't pump much at all and it lets you get more rpm. try it and see. It sure will be quicker and cheaper than buying new lifters and a intake gasket.

A little loose may cost 5-10 HP. Too tight - LOTS! Proven on dyno's. By the way......spring pressure is NOTHING compared to the pressure still in the cylinder at bdc times square inches of valve when you try to open it. Ever wonder why exhaust lobes on flat tappets go first?

[91CoupeMike]

Ok, I have some questions.

The valve springs Brodix says I have are the comp cams 987 springs, they list this as the specs:

• Valve Springs:
1.470 Hydraulic Roller Valve Spring -
CC 987, 125 lb Closed, 325 lb open,
1.900 Installed Height
.575 Maximum Lift


But on summit the specs differ.

Comp Cams#249-987-16
Dual Valve Springs
Outer inside diameter: 1.070"
Inner inside diameter: .697"
Seat load: 121lbs @1.800''
Open load: 343lbs @1.200''
Coil bind: 1.150''
Rate: 370lbs/in
With damper

And Info here shows something else:

http://forums.corral.net/forums/5-0-5-8-engine-tech/850893-beware-comp-987-16-valve-springs.html

And the guys on ls1 tech are saying they run them with no issues with .590 lift and 6k+ so wtf? They are running them at 1.8 installed height.