rocker bolt tightening
Well if you don't torque them enough, obviously they can come loose. Too much they can break the bolt or pull the threads out of the cylinder head. Best bet is to torque to spec. Borrow a TQ wrench if you don't have one.
Jon
Jon
I think he meant torquing using the TDC method. I personally have never used that method, as I feel it's a waste of my time and I've never had one rocker come loose or fail. So, just torque down to 22 foot pounds and enjoy your day!
I have wondered the same thing. I tried it both ways and it felt the same.
Funny, I got a PM the other day from someone who followed the methods that result in "no problem" rather then GM's method, he was shopping for heli-coils to repair his stripped rocker threads. The GM procedure is very easy to follow and there is just no reason not to.
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Verdad Gallardo they were torqued to the proper spec i believe, just not in the order or manner that gm specs. they just seem noisy compared to b/4 when i had a ls1 cam in my 5.3. i am using the stock p/r on a pat g 218/222 cam .595/.597 lift w/.030 milled 243s and .041 gaskets. I was advised that i needed 7.375prs. put them in and it was noisy even after a minute or so. so i put the factory ones in and they were alot quieter. I was just wondering if the methodology of tightening the rockers down could of led to the noise.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
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From: So.Cal.
If the cam lobe is up, when you tighten the rocker bolt you're compressing the spring at the same time (the lifter plunger bottoms out)... i.e. the torque on rocker bolt has to overcome the spring pushing back, this takes some of the 22 ftlb, so the final torque on the bolt is less than 22 ftlb.
But, then people spin the crank once (or an odd number of turns) and go over the bolts again (this gets all of them to 22 ftlb)... the problem is when people spin the crank twice (or an even number of turns), this leaves some of the bolts at less than 22 ftlb.
But, then people spin the crank once (or an odd number of turns) and go over the bolts again (this gets all of them to 22 ftlb)... the problem is when people spin the crank twice (or an even number of turns), this leaves some of the bolts at less than 22 ftlb.
i guess i need to measure. i would like to put the shorter p/rs in if it will make the car perform better. all things considered, with the mill of the heads and the thinner headgasket, 7.375 sounds like it should be the right size. but oh well!
where can I find the proper gm procedure to torque the rocker bolts? Also is there a write up on how to check proper pushrod length? When you buy a package are they usually the correct length?
