Rocker bolts bottom'd out?
 

Hey guys Im just finishing up my first LS 5.3 build and had a question. I completely rebuilt the 862 heads and noticed yesterday after installing the heads that when trying to bolt the rockers down, they wouldnt. I did have the heads milled 030''. Im using beehive springs for the ASA cam thats installed. It has brand new comp 7.400'' pushrods. It seemed like the rocker bolt was almost all the way down and there was alot of slack in the rocker? I didnt compress the spring very much bc I didnt want to break anything. The motor has head studs and stock MLS gaskets if that makes any difference. Do I need to buy shims now bc of the heads being cut? any help is greatly appreciated. Sorry if this is a dumb question, this is my first ls build and i have always used stud mount style rockers on my other engines.

Did you check you pushrod length?

Two things: 1) make sure you're on the base circle of the cam when you torque down - tho if you're on the lobe, the rocker will compress the valve as you torque the bolt down. 2) If you're still loose after torquing to 22ft-lbs you most definitely need longer pushrods.

Get a Comp pushrod length checker for $20 and throw it in there, adjust it by rotating the length out it until it just barely touches the rocker. Once all the slack is out of the system, but with no preload on the lifter, you're at 0 lash. Take the checker out and count the number of turns it takes to get back to you're starting length. Add your preload to the length on the Comp checker (6.8" + number of turns x .050") and order pushrods of that length.

Agreed with Jake. Another thing just to be sure, and I've seen this happen, you do have the rocker pedestals on right?

Lonnie

Good point. Make sure the rocker rail tabs are securely against the heads. If they aren't secure when you go to torque down, they will walk around and the tab could be caught, pushing the rockers up.

thanks for the help guys, you were spot on with the rocker stands. one i noticed the gm was upside down so I flipped and it cured the problem.