I'm looking at head studs in the near future, so me gots a question.
I have noticed that the ARP studs are used often, however PDR has some Haisley studs. Is there a difference between the sets or are they basically the same.

 

Haisley studs are manufactured by A1 Technologies.

 

Basically the same. You can get as much ... difference of opinion on A1 versus ARP as a good tranny war.
I needed studs when only the A1 was on the market. Never gave them a second thought on waiting for ARP.

 

i would go with anyone other than ARP. I broke two of them during the torque sequence when I installed mine. I have the pics somewhere but haven't posted them yet. Doug at PDW was awesome while all this was going on and got me another one no charge except for the overnight freight. The second one that broke got replaced with a stock head bolt and torqued the same. I don't have much faith in ARP anymore. I would make sure you do the install by the book and then re-torque the head when it's hot.

 

Thanks for the replies.

Kipo that sucks, what was the reason the studs broke, and did you have to pull the head to remove or did you improvise?

 

There are a lot of people that have had no problems at all including myself with arp studs.

 

I agree for the most part that people haven't had any problems with ARP. But, the reasons mine broke are still a mystery. Doug at PDW and Micheal at Hot Rod Diesel think it was just a bad batch. Doug did some research and found out several people had the same problem over the last six months. Whatever it was I'll end up buying another set when I get around to rebuilding my motor which really sucks. I'll end up buying another brand for sure and go bigger to be on the safe side. The first one that broke broke at the threads in the block. Since they were tightened then backed out, it came out pretty easy. The second one broke the threads on the cap. They just rolled over and wouldn't tighten anymore. I took the whole stud out and installed a stock bolt.

Good luck whatever decision you make, and make sure you buy plenty of moly lube.

 

Is the metalurgy the same? I'm confused after reading all the threads on ARP being stronger (tensil strength). Or are Haisleys (A-1's) different from what was being compared to ARP's over the last yr or so?

RJ

 

Kipo, what a pain. I think I would have the same feelings as you torwards arp if that happend to me. I think I got one of the first batches and have been fine for numerous retorques.

 

Here's Haisley's page on A1 parts http://www.haisleymachine.com/Head%2...0&%20Studs.htm
I blew the head gasket and decided studs and not bolts. I went with A1 was that was the only set available at the time. Either A1 or ARP is much better than bolts.