Cliff notes: snapped ARP head bolt at less than 50 ft/lbs of torque and stripped another upper head bolt hole during reinstall. Need advice on repair or replacement.

What a day. This was supposed to be an easy lifter and head gasket replacement. Pull heads off, change the stuff, put heads back on. I'm using ARP bolts which were installed with the heads, and I intended to re-use them for this swap. So here's what happened...

Everything came off just fine. Swapped the lifters, cleaned up the heads, made it all pretty and clean. I put the heads back on the car and started to tighten the bolts in sequence. When I got to the upper five, I noticed the most forward bolt felt a bit "mushy" on the torque wrench - that is, it wouldn't continually get more difficult to tighten, and the torque wrench never "clicked" when ramping the sequence up to 50 lbs/ft. I pulled back, checked the wrench against the other 4 bolts - all gave me a nice "click!" on the wrench. Moved back to the most forward bolt - two, three more pulls, then SNAP! I popped the bolt in half. I got the head back off and there was just enough of the bolt sticking up to get a pair of pliers on it a twist it out. Clean snap about an inch up the bolt.

Since no replacement ARP bolts were available this evening, I decided to get stock replacements. I chased the top row of threads and got out a little dirt and junk, but nothing serious. I brought the new bolt set out and started the sequence again. This time the CENTER bolt in the top five felt a little mushy. I handed the ratchet over to my helper and he gave it a quick turn and the bolt just spun in place. Stripped the CENTER hole. Two of the other bolts were not tightening properly - again, just not getting tighter as I continued to rachet - so I called it quits. Obviously, they are headed the same direction...

So what should I do at this point? Am I stuck with a heli-coil or an equivalent? Should I stud the top row? And why the heck did this happen in the first place? Who snaps an ARP bolt at less than 50 ft/lbs of torque? And why did my threads just melt away after a simple bolt removal and retightening? All the bolts seemed tight and seated properly when removing them. Something just doesn't seem right here. Any suggestions are welcome - from the best way to repair to the cheapest replacement short block in the DFW area. Thanks!

 

Rather than something not being right, sounds a little to me like you just had a tremendously bad string of luck there. I'd probably talk to ARP about the head bolt because that should NOT have snapped at under 50 ft/lbs no matter what.

As for the stripped holes.......I'm not sure a helicoil can be installed in the block like that. I want to say that yes you can and it's just a matter of pulling the head, getting the right helicoil kit, and going to town, but I'm not 100% sure that's going to be the case.

Best of luck to you, I feel your pain when nothing seems to go your way.

 

are you tq'ing one of the 10 BIG head bolts OR one of the SMALL 5 top row bolts???????????????????????

at a min., grind a groove in a stock head bolt to clean the threads, spend an hour w/ a shop vac and paper twls to get the coolant out

 

The 5 small bolts are supposed to be ~22 lbs. Drill and tap the stripped hole a little bigger. Those 5 bolts don't seem to do much after you haved torqued the large bolts down to 70 lbs.

 

I'm in DFW and went through similar problems last week. I had an ARP stud shear into 2 pieces and it was 3.5" deep inside the block when torquing to 70 ftlbs (this was the middle row, or top row of the big studs - not the little ones)! Luckily, I got it out... Called ARP and they sent me a new stud. Also ordered from them the correct tap to clean/chase the threads. Don't waste your time looking for a local shop that has the tap - the pitch used is rare and nobody has them. Kent-moore specifically made a tool set for GM to repair threads and remove broken head bolts, but it's expensive. GM recommends using time-sert fittings as opposed to helicoils. Go to time-serts homepage and check for local dealers - there is one in Carrolton who has the correct ones in stock. I also called several shops with my problem and most didn't want to mess with it. Try calling Patrick at Quality - he offered to order me what I needed.

Goodluck! I too thought I'd need a new block, but lucked out this time. If you're interested in using my tap, let me know...

 

Thanks guys - my big mistake here. I tried to read the shop manual... what a piece of junk. WAY too vague on pocedures. And I'm talking about the top five, unfortunately. I'm sure I can get all but the center bolt to torque to 22 lbs/ft, but the center will need attention. I'll give Patrick a call as well and get the right bits in. My f-up for sure, but dang it, I went over that stupid manual time and time again. Wow. It can be fixed at least - that's a relief. Thanks again.

 

If I feel head bolts get "mushy" I usually stick a straw on a vacuum down there. In my experience it's usually liquid in the holes. Helicoil should work well.

 

Do you have the correct manual? What is vague about this?

# Tighten the cylinder head bolts.
Tighten

1. Tighten the M11 cylinder head bolts (1-10) a first pass in sequence to 30 N·m (22 lb ft).
2. Tighten the M11 cylinder head bolts a second pass in sequence to 90 degrees using the J 36660-A .
3. Tighten the M11 cylinder head bolts (1,2,3,4,5,6,7,8) to 90 degrees and the M11 cylinder head bolts (9 and 10) to 50 degrees a final pass in sequence using J 36660-A .
4. Tighten the M8 (11-15) to 30 N·m (22 lb ft).
Begin with the center bolt (11) and alternating side-to-side, work outward tightening all of the bolts.