First off, the car is a '88 GTA with a L98 350. I have installed the LT4 hotcam kit (complete kit), and a TPiS MiniRam, as well as a set of WP Torquer S/R heads. The problem that I am having is the rocker arm (1.6) is touching off the rocker lock when the valve is closed. It is actually wearing a groove into the rockers. This can't be right. I realized the problem when I had to tear down the motor after a pushrod bent and broke, the lifter for that pushrod broke, and the rocker stud broke off. What is going on??

The heads are a direct replacment for my motor according to World Products. They have the same holes for the pushrods etc. The springs I am using are the ones that came with the hotcam kit. And you are supposed to be able to use the same pushrods and lifters. So I have no idea what is going on. Has anyone heard of this problem??? Please help!!

 

It sounds like your pushrods are too short. Take a look at the wear pattern on the tip of the valve stem. It should have a wear pattern approx. 1/3 the width of the stem, centered on the stem. If the wear is closer to the lifter valley then your pushrods are definitely too short. This can cause bent rods by putting an off-center load on the rod.

You DO have self-aligning rockers, right?

 

Yes I do have self-aligning rockers. The pushrod length is a conclusion we have come to as well. Having some shipped in over night, I'll know by tomorrow evening if that is the fix!

 

I agree your pushrods may be too short. It can definately hurt rocker arm geometry. Another thing to be aware of, the GM rr's that come with the LT4 Hotcam kit are made by Crane, but they are not identicle. The slot in the GM version is shorter. If the head's rocker stud geometry is the slightest bit off, the poly lock can contact the end of the slot and break the rocker stud and more. Also, I've seen the hex on the Crane & GM rr's contact the top surface of the rockers, and this will wear into the top. I had this on my Trick Flow heads even with longer pushrods. It seems Crane and GM may have made the rockers slots deep, the 6 pt hex poly locks short (so as to clear the stock valve covers), thus leading to contact on some set-ups. This can also cause loading on the rocker stud leading to failure as well.

One solution is to discard the Crane/GM poly locks in lieu of some from ARP that don't have the large hex. They have a small 12 pt top that would be totally inside of the rr's slot envelope. The only thing you'll have to check is the overall height of the ARP locks, as this may present a problem under some stock style/height valve covers (like the centerbolts).