A bit long...but here's the deal. Was cleaning the deck surface on my block for my new HC install. Noted that one of the studs was sitting a bit higher than the others, like over a 1/4 inch higher. It's the 2nd from the front on the passanger side (middle row). It's the stud in the middle row that is longer than the others.

Anyhow, removed the stud (needed an allen-head socket for this) and found that the previous shop who origonally installed the studs NEVER cleaned all the coolant from the boltholes. F'ers....glad they went out of business, as I've now been pulling studs and cleaning bolt holes all evening.

So, cleaned the hole till it was spotless (checked it w/ a flashlight). Put ARP moly-lube on the stud threads and reinstalled. Started threading it by hand. No issues. Moved on to the allen key. No issues, till it got to the point where it was before. Had to switch to the allen-head socket. Was getting to the point where it required about 15-20lbs force to tighten. Tightened till the allen key slipped in the head of the stud. Didn't want to mess w/ it any more and strip out the allen head on the stud. It's tight enough now that I can't loosen it w/out risking stripping the allen head on top of the stud. Every other stud I've been able to "bottom-out" using only an allen-key w/ little to no effort.

So..... now the problem stud is about 1/16" to 1/8" higher than the others in the middle row.

Think this will pose a problem? Should not be in danger of the head stud nut bottoming out on the shank of the stud. Wondering if it could cause a false torque reading when torquing the stud nut? Don't want to lift a head gasket.....

Also don't want to make matters worse (cause they're not that bad now....so I'm not going to do anything crazy, like pull the motor, etc.)

So, think I'm cool considering the current situation?

$0.02 appreciated. Thanks.

 

Instead of tightening it with the allen key, use 2 of the hex or 12 point(whichever you have) bolts tightened up against each other to tighten the stud any further..

 

I think he meant the nuts stacked/tightened against each other. Then carefully tighten the stud the rest of the way. Then break loose the top nut off the bottom one.

 

Not a bad idea...... Hate to put that much torque on it and risk breaking the stud, though. That would be a problem.

BTW, using the 12-point nuts.

 

ARP makes a thread chaser, it is expensive but will straighten out the threads. You don't want to use a tap as it will cut the aluminum and change the thread fit. SDPC carries them. I have the part number at home.

I would also examine that hole very good for cracks to ensure they didn't crack the block with the fluid in there. Sounds like they didn't as it would be harder to do with a stud vs. a bolt, but check it out good.

 

Appreciate the info. Yea, I was checking all the holes I could see for cracks (used an inspection mirror for a lot of them). The car ran like this for a year....so I'm guessing I should have noticed if the block was cracked.

I thought at first that coolant had seeped into the holes when I removed the heads, which I was suprised about cause I vacuumed the water jackets before removing them. Then when I removed the studs I realized it was red "dexcool" in the holes......and the coolant was flushed/switched to the good-ol green stuff when the heads were changed.

 

Just make sure if you do it to use a hex nut underneath or you might not be able to get them off after. Also, if it takes that much torque to turn it that you are worried about breaking a stud, then I would consider taking it out and chasing the threads as vettenuts suggested . If that doesn't work then it's, re-tapping and installing a helicoil.

 

Yah ... I'd remove the stud, clean the hole and then try again especially if you are finding old coolant.

 

Just went through this with my iron block 6.0. Rust & crud does build up in there, though I don't see how. It is a special thread but GM recommends not using anything in there, no tap no sealant, locktite ,nothing. I ground two flats on a stock bolt and ran it down in a couple of times and blew it out. That helped but was real nervous about doing it. Ended up using just a touch of moly paste on the threads too, they were dry in that little bit of rust but any more and it might have hydrauliced and cracked the block. Wish GM could have done something better.

 

The ARP thread chaser works great, you would be surprised at how much sealant/junk comes up when you run it in there a few times. It is pricey, ($20-$30 IIRC) but is specially designed for the long reach LS thread arrangement.