So im going through the whole torqing sequence to put my new heads on, go to tighten one of my ARP head bolts down to 85lbs AS RECOMMENDED by the MANUFACTURER and ping, it breaks off.


So i guess now i get to pull the head back off and try to get the f**king other half out. THANK YOU ARP!

 

I had the exact same thing happen to me when I was building my 383, I was doing my last torque sequence to 65 ft/lbs and one of the short outside lower bolts broke and I was cursing ARP as well. I also had an ARP cam bolt break when I was torquing it to 25 ft/lbs. Luckily when I took the head off the bolt had broken in such a way that I was able to use a screw driver and small mallet to back it out enough to get some pliers on it and get it out without machining. After that expirence I installed ARP head studs and everything went fine just remember to run a thread cleaning tap through all of your bolt holes first and don't forget to put thread sealant on the bolt/stud threads.

I also have the AFR Hydra-rev kit on mine and I believe that had something to do with my problem. With the extra spring pressure pushing against the head bolt torquing down, that might have helped cause the failure.

 

I thought those were some of the best bolts you could buy.

 

Mine was one of the shorter bolts on the outside also.

I thought they were the best you could buy too heh

 

Just called them, they are sending me a new one...which will be here NEXT FU**ING WENSDAY!

I want OVERNIGHT god dammit....man this sucks

 

If a bolt breaks off in the block, how do you get it out?

 

Where did the bolt break? In the threads or on the smooth area between the threads and the head or under the head? That answer might clarify why it broke.

 

You can use screw extractor (aka easy out). You drill a small hole into the center of the broken bolt. Then you take this thing that looks like a f'd up left handed drill bit and stick it in the hole and then set your drill on reverse.

 

You can also weld to it and grab the weld with some vice grips and spin it out that way.

 

the bolt broke about 1/4 inch down from where the threads start, no marks on it, just looks like it twisted off.

I got the broken part out easy, pulled the head and there was enough showing to get some vice grips on it, and it came right out.

 

85 sounds excessive, though you say it was recommended. The GM manual says 65. That's a big difference. I actually used the torque/angle method when I installed mine. With that method, the short bolts don't get tightened as much as the long ones do. Shorter bolts=less stretch and therefore don't have to be turned as far to reach the same clamping pressure as longer bolts.

 

From the sheet that came with the bolt:

Torque values are based on 75% of the fasteners yield strength. Use the manufacturers torque sequence but do not use the engine manufactureres turque specs. Torque the bolts to 65 ft lbs ARP Moly assembly lube, or torque to 85 ft lbs with 30wt motor oil.

I didnt have any ARP moly lube laying around and couldnt find any local so was using motor oil.

 

I know this doesn't help now, but in the future, if you're torquing the bolt, getting close to the final value, and suddenly the torque stops increasing but the bolt keeps turning, then STOP. The bolt is yielding at that point and is about to break.

Of course, if you're using a "clicker" torque wrench you won't see it happening.

It sucks, but I've never had one break on me (knock on wood). I usually torque mine to 65-70 ftlbs.

Also, another thing to do is use black RTV on all the bolt threads rather than oil on some and RTV on the others. That way all the torque is equal. (In case you didn't know, you need to use RTV on the threads that go into the water jacket.)

-Dave C. '97 Z28

 

Thanks for the info dave, i will use RTV in the future.

 

If you tried to torque the bolts with lube to 85# you are lucky the bolt broke and didn't pull the threads out of the block.
I have pulled ARP's to 120# dry and no problems.With ARP lube (which you should have) they torque to 65-68#.
Where the new?
I'm sure out of the thousand's of bolts per day that they make,there are some bad ones.