Well there ya go, nevermind me

The final pass on my CA625 studs was 110ftlbs

 

Holy crap!

 

A while back I bought a set of rocker arms with the trunnion upgrade. I cleaned them off and decided to let them soak in oil overnight before I install them.



I used little aluminum loaf pans. How cute! LOL



My helicoil kit showed up.



So I cleaned off the valve covers and taped off or plugged every hole I could. That way when I drill the head for the helicoil I won't get any aluminum flakes in the engine.



Here is the hole I drilled in the head to extract the exhaust stud. I drilled it using the factory manifold as my guide.



And here's the problem. The drill bit that the helicoil tap requires is 21/64. Here it is centered in the hole I drilled previously.



As it turns out, I only drilled out half the broken bolt, so there are already a few threads in that hole. Here's what I'm thinking. Drill out the rest of the threads and install the helicoil. Then use JB Weld to fill in the gap. What else can I do? It should be plenty strong because the thread depth exceeds the stud diameter.

It's JB Weld or leave a gap. Thoughts?

 

Use a bigger size helicoil and bolt and drill out the manifold to fit.

 

Atomic's suggestion is the easiest route but I hate having different size bolts on something when I go to work on it. So here is an option similar to what you were thinking... Put a single wrap of thin tape on the drill bit, install in hole, epoxy gap. I have also seen plastic straws used if the diameter is correct. When cured, remove the drill bit, redrill then install helicoil.

 

I could also fill up the entire hole with epoxy and drill/tap all of it. Or I could screw in an old exhaust bolt and fill with epoxy then drill. Or epoxy in the stud. I'll have to think about it.

 

I've got a bit of an update for you guys. First off, here are my lifters.



Now, I'm running the Z06 cam, LS9 head gaskets, and those LS7 lifters. I've got 7.425 pushrods that I just installed with trunnion upgraded rocker arms. Does 7.425 sound about right?

I cleaned up the rocker guides and installed the push rods.



Installed the rocker arms and torqued them down to 22 ft/lbs.



I actually have a Comp Cams 7905 push rod length checker. The problem I'm having is this... In my mind, the lifters should be solid (or full of oil) to be able to check for push rod length.

I'm imaging swapping this 6.0L in, running it, and then checking for push rod length. I know it's a guess, but with that cam setup, I'm thinking 7.425 is just about right.

I wasn't planning on swapping the LQ4 in this soon, but I don't have to go back to college until the 4th. I'll do some googling, but I bet swapping a 5.3 for a 6.0 doesn't take that long.

 

I would definitely go with drilling up to the next size helicoil/bolt. Helicoil makes inserts called twinsert and they have the same ID but a larger OD. It's just a thicker insert. (Just checked twinsert is 2 helicoil meant to lock together, McMaster has the thicker bush type inserts that require a 10.8 mm and one that takes a 29/64" drill)

I really don't like the epoxy isea. What epoxy would you use? Check the temp range rating and make sure it can stand up to the temps. There is only about an inch of solid aluminum there between the bolt and exhaust port. Aluminum is pretty highly thermally conductive. The bolt will probably be really close to the temp at the wall of the exhaust port.

 

I have never had good luck with jb weld or any epoxy for that matter on things that get hot. I striped the bottom bolt holes of my oil pan at one point and used helicoils to I think 7/16" bolts and they are super solid so I am very happy with that. You might could find a 2 size stud for the larger helicoil if you want them all to be the same...maybe a M10 on one side and M8 on the other.

When I use my pushrod check checker I dont torque the rockers down all the way right off, I gradually do it until the rocker is snug to take out the slack there. If I keep tightening it it will compress the lifter like you described if the pushrod is too long. Its a by feel thing, but you can feel when the lifter starts compressing.

 

Not that anybody asked, but here's my opinion.

When you tightened down the rockers did you happen to pay attention to how many turns past "zero lash" until torqued to spec? (with the cam on base circle) If you had about half a turn you should be in the ballpark.

As far as checking with the tool, the way I have always been told was to shorten the adjustable pushrod until you can torque the rocker down to spec with "zero lash" or basically at the point where the rocker just barely puts any pressure on the pushrod and lifter. Then measure the length of the tool and add the amount of preload to it you desire (say 0.060"), and that's your final length. When I did a VVT cam swap in my 5.3 with LS7 lifters, I went from 7.400" pushrods (stock) to a 7.350" to get the right amount of preload.