ARP STUD INSTALL BLOCK THREAD FAILURE

[kcwright1979]

I spent the better part of the other day installing my ARP head studs, cleaning out the holes and using a bottom tap to get them as perfect as I could. Soooooo as I was installing my nicely bulit heads that I got back from the shop yesterday with new pre cups and comp 910-16 springs and my expensive A$$ gasket set using the arp ultra lube and set the studs in the head afer I got them down, screwed them till they touched the bottom and lubed up the washers and nuts. First pass 40 ft-lbs no problem second pass 80 ft-lbs no problem. Took a break and came back third pass 125 ft-lbs one side done went to the other side and got halfway through and heard a loud SNAP and the stud went loose went to tighten it down and it just spun, pulled the bolt and ran a swab and found thread parts in the hole . So now I am going to buy a helicoil set 1/2-13x1inch rated at 220,000 psi and a long drill bit 33/64x12inch to fix the 6 holes that are bad using the head as a guide. Has this happened to anyone else or am I just the bad luck king. (I called ARP and told them my situation and the guy said in 16 years he never heard of this happening)

 

[laserjock]

Are you supposed to bottom them out? I don't know just asking.

 

[BrandonMag]

FWIW, I haven't ever heard of a properly installed ARP stud breaking. Gary will chime in, he has much more experience with ARP.

 

[kcwright1979]

the instructions said thread them in finger tight so I did. And sorry if I wasent clear enough it was the block threads that failed not the stud threads.

 

[G. Mann]

Is it possible that your torque wrench is out of calibration?

Just trying to think outside the box for a bit. The only time I've ever broken a head bolt on assembly was when I was re-using the old head bolts. Clearly, in that case, the bolt had already started to fail because when I recovered the broken piece I put it under a microscope and could see where it had been cracked at a thread.

But.... for brand new high dollar studs to break.. new one for me. Please keep us up to date on what you find, since I just got my new set of ARP high $$$ studs and have not yet installed them.

Question: The stud fail at the block end? The piece that you pulled out [not the piece remaining] did it fail at a thread, or at the base of the threads at the stud?

[Threads on high strength studs are rolled not cut, and then heat treated, if there is error in the rolling of the threads, it could induce stress cracks on heat treat] If that is what caused failure, then it is likely a build lot problem, not just a single stud.

Thanks.

 

[marmot]

So the stud did not fail? I don't think thats a problem with arp products. Why do you need to fix 6 holes? guess I dont understand....the issue was with one hole correct?

 

[IDIoit]

in my unprofessional opinion, the problem is how you cleaned the threads
in dirty threads, that are torque sensitive you do not use a tap.
a tap will actually cut the threads,there is a plastic (dont know the exact material, but its plastic like)
set of thread chasers. its a 4 flute bit, just like a tap.but will not cut the metal, its designed to just clean, and nothing else.
i crindge at using heli-coils on head bolts, but what more can you do?
i wish you the best of luck.

 

[G. Mann]

Ohhhhhhhhhhhh Crap !!

Sorry, I didn't catch that on the first read.. Thought it was stud failure..

So, torque pulled the stud out of the block threads .. Hmm .. is it possible you chased the threads with wrong pitch tap? Or.. was the threads in the block damaged to start with from rust or something?

The stud set I got from ARP has an indent in the head end for an allen wrench. My idea was to "hand tighten" them using an allen wrench, into the block.

Those of you that have done it.. is that the way?

 

[marmot]

Something like this https://store.snapon.com/US-Thread-Chaser-Sets-Set-Thread-Chaser-Internal-U-S--P635190.aspx not taps

 

[marmot]

Ohhhhhhhhhhhh Crap !!

Sorry, I didn't catch that on the first read.. Thought it was stud failure..

So, torque pulled the stud out of the block threads .. Hmm .. is it possible you chased the threads with wrong pitch tap? Or.. was the threads in the block damaged to start with from rust or something?

The stud set I got from ARP has an indent in the head end for an allen wrench. My idea was to "hand tighten" them using an allen wrench, into the block.

Those of you that have done it.. is that the way?

yep

 

[kcwright1979]

I used a 1/2-13 bottom tap the ARP tech said it was needed to clean the threads. one hole compleatly stripped out. five more of them partially let loose but then torqued down. I checked my brand new torque wrench against another one and it was good. some of the holes had alot of rust in them which probably in turn weakened the threads live and learn I guess.

 

[marmot]

I used a 1/2-13 bottom tap the ARP tech said it was needed to clean the threads. one hole compleatly stripped out. five more of them partially let loose but then torqued down. I checked my brand new torque wrench against another one and it was good. some of the holes had alot of rust in them which probably in turn weakened the threads live and learn I guess.

Bummer, best of luck getting her straightened out.

 

[FORDF250HDXLT]

so the thread title is false:
ARP STUD FAIL

should read:
ARP stud install,threads in block fail

major bummer brother.sorry to hear of your misfortune.

 

[icanfixall]

I bet the holes that failed or about to fail are the ones at the bottom of the head. Those are actually exposed to the air. They are made kind of odd in that sense. Sorry but I can't add much to this new problem. I think your biggest hurdle now is drilling down deep enough with the head on the block. Might be able to find a jobber drill bit long enough. then getting the heli coil down the head into the block might not work with the head on the block. Before you go off and drill know this. The block is counter bored 1 inch before you reach any threads. Then the threads run down into the block 1 1/2 inches. DO NOT DRILL THRU THE BLOCK INTO THE WATER JACKETS.

 

[FORDF250HDXLT]

so you show multiple torque steps of the studs but this shows just once is the ticket:
http://issuu.com/arpbolts/docs/ut_details/1?e=1984007/4062479

not that,the threads wouldn't have failed anyway but i just went to look at the instructions is all.i think i personally would just go find another block.the reason being,is that there isn't any shortage of them and there's no time like now.
needless overkill?
good peace of mind?
i mean,your installing studs for what reason? peace of mind right?
if these engines were getting scarce that would be one thing,but with them so plentiful.man.i dunno.i really doubt she'd be going back in my truck.