[ajzride]

I'm starting to work on the list of the things that bugs me on the car, and one of those is how noisy my valve train is.

Background.

New AFR 185 Heads (2.02/1.6) valves preassembled with valves and springs
New Comp Cams High Energy Hydraulic Lifters (stock size)
Stock Rocker Arms (Stamped Steele Pedestal Mount)
New Comp Cams 35-600-4




Checking pushrod length on a random lifter gave me 8.150" (stock length)

So I got a set of

New Comp Cams 5/16 x 8.150" pushrods


I knew when I assembled the motor that I had 2 or 3 rockers that were a little loose, but I assumed it was due to worn out rockers, and since I intended to install a pedestal to stud rocker conversion this winter, I decided to table the issue.

Now that winter is here, I am going to have to put off on converting to stud rockers so that I can spend the cash on getting the exterior of the car finished, but I still want the dang sewing machine noise to go away.

Given that I am using pedestal rockers, there is no way to adjust lash and pre-load like on stud mounts. You simply bolt them on, and torque them, regardless of lash. You can shim them if you need to pick them up, but this will only make you need longer pushrods, and I already need longer.

I began by working on cylinder #1, I rolled the motor to get both valves fully closed, and check play. As you can see in the video below, I have significant play, looks like probably 0.05" of a gap between my pushrod and my rocker when I seat the rocker on the valve.

YouTube - Rockers

YouTube - Rockers

Since I though the problem was the rocker, i swapped the intake and exhaust, but the problem didn't move. So I swapped the pushrods, but the problem didn't move. That means that the problem is either

A) Intake lifter is (partially) collapsed
B)Cam Lobe profile is causing issue

I rolled the motor over to close both valves on #2, #3, and #4 in turn, and sure enough, all of the intake valves have play, although #1 has the most. None of my exhaust valves have any play. This leads me to believe that the problem is B, and not A, I would find it really hard to believe that All of my intake lifters were having problems, but none of my exhaust lifters were having problems.

Looking back at my stock heads, I have valve lash caps on the exhaust valves, but not the intake valves. This would lead me to believe that the exhaust valves would be the side that would need longer pushrods if the sides were going to mismatch, but that is not the case.

The motor seems to be running fine, it is making plenty of power, it is just noisy. Just to be double sure, I ran a compression check, and numbers look good:



Is this due to the fact that the cam specs say that valve lift and lobe lift are different for intake and exhaust? The gap in those numbers (0.008" and 0.015") seems small compared to the play I seem to have in my rockers (0.05")

So on to the real questions:

A) Am I hurting anything running it like it is?
B) Is this common, to have different length pushrods for intake and exhaust (I saw it some on the LS1 forums, but haven't seen much on the ford side)?
C) Do I need longer pushrods for the intake side, or do I need some lash caps to tighten up the valve side?

Thanks Guys