Yes, I torque all 16 rocker bolts to 22 ft/lbs @ TDC on the 1st cylinder. Then I turn the motor and torque them all again to 22 ft/lbs (basically a torque check..). How does this produce a different result than the one posted above? All of the bolts were torqued at their base circle regardless if it was on the first pass or the second.

 

^^^^ you are only supposed to tighten the 8 rockers. they wont all be sitting on there base circle at the same time, tightening them and compressing the spring at the same time can be real bad and possibly strip the threads out the head.

 

This is what I was trying to explain, but sometimes ordinary people with little to no experience just happen to be smarter than the trained engineers that designed this ****. Go figure.

I have seen many stripped heads that I have had to drill out and heli-coil because people have tried to tighten the rocker arm bolts against the spring pressure. Follow the GM procedure which puts the lifter on the base circle so it does not compress the spring while you tighten it down and don't listen to LS-1Z28 when it comes to this. Laziness will usually end up costing you a lot in the long run.

 

No they weren't tightened on the base circle. Those off the base circle and tightened on the first pass were fighting the valve spring. The resulting bolt preload will be different. Torque is being used as a measurement of bolt stretch (preload) and it is highly dependent on friction. Friction load is dependent of the force applied to the thread, which when opening a valve is different then one that isn't. In the end the bolt values will be different. If you set your torque wrench to 15 lb-ft and tighten a bolt, then reset it to 22 lb-ft and check it, you will likely find the bolt won't move. These are some of the reasons why ARP wants you to use their lube, it controls the friction you are using to measure torque.

 

Actually haven't heard of that happening before. A quick search and found a couple threads where people have stripped their rocker threads because of this.. When I was tightening mine I did see the springs compress but I definitely didn't feel nearly enough resistance to strip the threads. In fact, I didn't feel much resistance until the rocker bottomed out on the bracket. Guess you learn something new everyday.

I've installed the rockers twice now and haven't had any trouble but I'll make sure to tighten the rockers down only on their base circle.

Thanks for being persistent. Sometimes I can be kinda stubborn

 

LS-1Z28 we learn something new every day no one knows everything we all make mistakes learn from them and move on, people that don't accept their mistake are the ones that never learn and there is a lot of people like that in this industry

 

Thanks man. Cheers to that

 

glad i seen this for some reason two of my rockers came loose?? one bolt is streched my stuff should be here tomarrow and was wondering about the adjustment my buddy said on his vette he just top dead center then torqed them to 22ft/lbs...i would of had to beat him ....lol mines a 6.0 with #317 5.3 heads all the same right???

 

^^ same procedure. 22ft lb and must be on its base circle.

 

Glad to hear and no hard feelings!

 

Sonnaffa biscuit eater!!! I'm gonna check mine tomorrow, this is getting me all phucked in my head.

 

No, not quite... there are 2 TDC's: one has both valves open (overlap, both valves are ramping), the other has both valves closed (both valves are on base circle).

Follow the Service Manual procedure posted above.