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New LS3 with 600 miles on it. TSP stage 2, TSP double valve springs, retainers, polished galleys via CNC. I installed the cam and Comp trunnion kit and used OEM bolts if the Comp bolt bottomed out. So there’s a mix of OEM and Comp bolts. Also used plenty of Lucas green assembly lube everywhere.
Noticed clacking sound a few days ago at idle for 20 seconds, then went away, and was dismissed as lifter bleeding. Today after startup clacking didn’t go away, so I pulled the valve cover on that side.
Noticed a rocker sitting on its side with the upper half of the OEM bolt still inside it, and 1/8”’of the snapped off shank sticking out of the head. I’m going to grab the head with vice grips and take it out - only 22 ft-lbs so should come out. I also have plenty of OEM and Comp bolts.
Question: I can remove the entire set of rockers from that head using an air wrench with stress on valves, correct? It’s only putting them in and torquing each pair of exh & intake when each cylinder needs to be TDC, correct? (Obviously anything pulled needs to kept in order — bolts and rockers. I can leave push rods in).
I would not use an air wrench on the remaining bolts just a breaker bar and a rachet. You can use the air stuff after they are loose. I am wondering how this broke in first place.
I would not use an air wrench on the remaining bolts just a breaker bar and a rachet. You can use the air stuff after they are loose. I am wondering how this broke in first place.
Yes, I just used a normal hand-held ratchet-socket and loosed the rocker bolts until they were loose, then spun them out with the air wrench.
It would be due to greater stress on everything, because of the double valve springs and greater valve lift of the stage 2 cam. OEM cams have 0.55” lift while stage 2 is 0.6-0.65”. The Comp kit bolts are a beast whereas the OEM bolts have thinner shanks.
On another note, from an engineering standpoint, I actually don’t like the thought of this happening, because it could happen again. Does anyone make heads for an LS3 that are a good match for stage 2 cams? I mean good springs-retainers, stronger bolts, better roller rockers, stronger castings where rocker bolts are. Basically, plug and play, with low risk of upper end failures?
I almost want to say that the rocker arm pedestal was not centered correctly which put a bind on that rocker arm bolt. I always start the end rocker arms and one midway by hand to make certain the stand is centered. LS3 heads in stock form can handle .600 lift from a single spring so it's not the head but more so what spring for the camshaft application. The stock rocker arm bolt broke and this is the first one I've seen happen. I've used the Allen head bolts from COMP without issues so if it were me I'd chalk this up to a fatigued bolt and I wouldn't be afraid to run those Allen head bolts unless you find there's some kind of interference issue with the head of the bolt coming into contact with the rocker arm body when the valve is opening or opened.
Agree 100% with 01Camaro. I’d chalk this up to a simple fastener failure. I’ve never seen one break, even with 400+ lb dual spring setups. That broken fastener in the head has zero torque on it and should easily unscrew by hand. If it doesn’t, it’s binding somehow, and could have contributed to the failure.
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Snapped rocker bolt 
