Extreme Studs

J

jnp1267

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Joined
Jun 9, 2014
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14
Has anyone had success using Extreme Studs on an 0 ringed head? What did you tq too, because the instructions say 115 max, and i tq'd to 130 and still blew the studs with ease.
 
I had my head o-ringed with the grooves in the head only, using Haisleys head set with the .105" rings. I had a set of Extreme Studs on the motor and decided to use my new set I had on the shelf. I torqued the head according to the instructions, which was 145 ft lbs. if memory is correct. I broke a stud on the final torque. Jeff said I was only supposed to torque them to 120 ft lbs, not the higher torque. I told him I had this set on the shelf for a year. He has lowered the torque spec for this head studs, but agreed to replace my set with a new set. They were not going to get shipped out for a day or so. I needed a set to get truck back together, so I ordered a set of the ARP new age 625.
 
Not sure why i put blew the studs with ease i meant the head. I only o-ringed the head. Can remember the depth off the top of my head i will need to go back and check the ticket. But i did the initial TQ and went back after a couple of heat cycles and tqd to 130. uploaded all my tunes to my CSP5 and when i turned it to level 5 rolled into the throttle around 65 and when it lit, the oil started pouring out. Popped the hood and oil was covering EVERYTHING in the engine bay. Pulled the front stud outside of the valve cover and you can see where it stretched it. The tensile rating is comparable to the 625s but the tq specs are lower. So im guessing it doesn't matter with his studs even if you o-ring the head you still can only go so much or you will break them. For having such a high tensile rating you would think they could tq past 130, or at least enough to crush the head gasket enough.
 
I run his studs in my motor (12 valve) I also had my head o-ringed as well.011 protrusion iirc for the o-ring. standard thickness gasket. I followed his instructions to a t... and so far they have worked very well for me. Truck will see 75 psi on a hard pull no problems with hg sealing issues yet. When I spoke with him on the phone when ordering he was very insistent upon me not over torquing due to them being a very hard material.
 
I followed them as well and even ran heat cycles before getting into it. I havent had any luck reaching him at this time. When it went, according to my V2 it was just at 98lbs of boost, however im not sure what the drive pressure was.
 
Those studs are not to stretch is the thing. I've run them on 105psi of boost now it was a monster vp44 with top feeds which has far less cylinder pressure then your dealing with but do not ever hot torque these studs or go past that ft# mark and I would think I've read where o rings are good for 65-70psi? After that you want a fire ring I'm sure we all have different opinions on that matter but I'd say if your going to keep that truck at 98psi of boost just go 14mm head studs and forget about it I've tried almost everything but 14mm head studs and had failure with 120psi set up on a lot less cylinder pressure then a common rail!! Good luck man!!
 
Since you went with 625's, would you like to sell your replacement set of extrem's?
 
12 valve - Used bottom dollar ARP's and oring'd head have lasted four years on mine, with several retorques to 140ft/lbs. 18-20*, 100+psi, and no idea on drive pressure, but he351 secondary, so that'll give you a good idea. If the extreme's are really that hard, I wouldn't take them over whatever he says.
 
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