arp head studs

kenpobuck · #1 (**permalink**) 11-04-2009, 09:21 PM

I got my arp studs today and was reading the paperwork with them. It says to torque them to 85 ft lbs. but Chilton says to go in four stages, 40, 65in numbered sequence, then inline sequence to 75 twice. Do I just go in the numbered sequence once with the studs or follow the sequence in the book?

johnboggs21 · #2 (**permalink**) 11-04-2009, 09:52 PM

I would definitly torque them in stages. Probly should go with what the chiltons manual says.

symonds86 · #3 (**permalink**) 11-04-2009, 09:53 PM

normally you go with what the studs say, i called arp when o got the ones for my 347 and they said go with there specs because of the way they are designed. id call them and double check just to be safe

kenpobuck · #4 (**permalink**) 11-04-2009, 10:05 PM

I will call them tomarrow and find out. I am putting a lotof money into these heads and studs with the current economy and if I screw them up my baby will kill me lol!!

symonds86 · #5 (**permalink**) 11-04-2009, 10:24 PM

i hear ya that y i called them aswell ididn't wanna ruin 6000 dollars worth of parts over head studs being torqued wring

87crewdually · #6 (**permalink**) 11-04-2009, 10:29 PM

Torque in the sequence and values written in the book ending with the final torque value of ARP's spec.
This is where it gets crazy. You need to "untorque" in the reversal sequence and retorque them all over again IIRC 5 times. The reason for this is to pre stretch the new studs.
Learn from my mistakes as I didn't know this at first and replaced the gaskets again after a few hundred miles because the studs stretched just enough to weep pressure into the water jackets. Also I ended up torquing my studs to 106 ftlbs with no issues since.

Dave Sponaugle · #7 (**permalink**) 11-04-2009, 11:24 PM

When you install the studs, do use the pattern in the engine manual, starting in the center of the head and working out in a circle.

Also do it in steps like the engine manual specifies.

When you read the ARP paper, torque to spec and then remove a minimum of four times.
Then on the fifth install, you are good to go.

The install and remove four times helps the nuts and stud threads wear to each other.

And I payed rather close attention to how many turns it took to get to torque each time I installed mine.
The fifth time each nut turned about 1 turn farther than it did the first time I installed them.

Be sparing with the moly assembly lube, you don't want to contaminate the head gasket or mating surfaces with lube.
I wiped the head and block surface with acetone to remove all traces of oil before I dropped the gaskets and heads on.

kenpobuck · #8 (**permalink**) 11-05-2009, 07:17 PM

Thanks guys that is what I needed to know.

Marianna2003 · #9 (**permalink**) 11-06-2009, 10:43 AM

I believe that you are collapsing the gasket and seating it. The way metallurgy works, bolts are not rigid. Nothing is totally rigid. The bolts are like real tough springs. They normally stretch. The trick is to stretch them enough to hold the gasket in place under the highest pressures possible while leaving a safety margin for possible anomalies.