Head Stud Torque

[icanfixall]

I have 2 differing numbers on the last torqueing of my DPS studs. My International service manual states 100 lbs in the line sequence for the last 2 torques. I also have a member posting 110 lbs for the last 2 torques in the line sequence. What are your thoughts about 100 or 110 lbs. If I think long enough maybe it will work out like bolts 100 lbs and studs 110 lbs... I can't remember anymore...... Getting old... It sure is funny. Maybe sometime I'll forget to forget something and all will be just fine....

 

[Agnem]

These days we typically take them about 10 pounds farther than what the service manual recommends thanks to the turbo kit manufactures research. If your doing studs, your going to get an effective clamping force that will be much higher than what the normal "bolt" torque number actually gives. One thing is for certain, and I can't emphasize the importance of this enough.... get your torque wrench calibrated! Send it to a place like teamtorque.com who will also loan you a wrench for free while they set yours up. If your interested in this 10 pounds of torque difference, it won't mean a thing unless your wrench is right on.

 

[icanfixall]

Thanks Mel. I do have a torque wrench that has been calibrated not too long ago so I feel its correct but who really knows for sure. Thinking back now I do remember something about 10 lbs above the stock bolts when using a turbo plus the added clamping strength of the studs. I called an aerospace fastner manufacturing shop yesterday about making me some differant studs for our motors. They can roll stud threads on anything if I am able to tell them what the stud composition is plus whats the radius of the bottom of the thread. Another shop stated they supply the top fuel teams a h11 stud thats 9/16 inch and they don't ever break them. Thats about 220,000 compared to my DPS set at h13 I think with a 270,000 lbs breaking strength. Oh yeah the time for these was from 8 to 16 weeks because everybody is so busy this time of year. Both places were costly too upwards of $1400.00 to $1600.00.... I do have another shop to call but thats not something to do today.... Thanks again.

 

[typ4]

Hey Icanfixall glad to hear its going back together. I put arp 1/2 inch x 7 studs in mine this last time,110 ftlbs, not as tough as head studs but better than bolts by about half ,going by your yield test numbers. 2k on it and much quieter, no piston slap, good power, more boost with the bigger compressor wheel , too much fuel tho, can hit 1100 on the pyro really easy. Took out the grill and lost 15 degrees of engine temp, 225 down to 210 at 16.500lbs and a damn headwind going to and from Idaho.

 

[icanfixall]

Me too Russ. It will not be finished for some time. I just "found" some other parts I want to install and they wont be here for about another 10 days. Glad you are up and running though. What I looking at building was a stud that was around 7 3/8 inch long with more threads on the bottom for more block engagement. The DPS studs are about the same length and engagement as the stock bolts and we have more threads in the block that can be used. Its not needed but I just wanted to use them.

 

[typ4]

I told ARP that they would benefit from making a stud kit for our engines, he sent the request on to the powers that be, maybe we should all email a request and get them going.
The studs from them contact all but 2 threads in the hole and any longer will interfere with the rocker plates. I am going to work on a roller rocker setup as soon as I can find the right ratio, our rockers suck.

 

[jauguston]

If you use head studs with sae (fine) thread on the top you had better get the torque specs from the stud supplier. The factory numbers for coarse thread bolts will be meaningless.
Jim