After work tonight we pulled the engine out of the truck, tore it apart, switched in a set of forged rods and called it a night.
Tomorrow we will be completing the engine assembly and re-installing the engine.
As part of my build I have a set of new ARP head studs. The ARP instructions say to torque to like 80 lbs with ARP molly lube and like 106 with 30 weight oil...
I thought you had to tighten and loosen... then tighten and loosen.... and the final torque was more like 135????
Can some body please guide me!!! What is the best sequence and torque spec on new ARP head studs...
When I did mine I was also a bit confused. I know the type of lube does make a big difference. I wound up doing 120 with oil. They held with OEM headgaskets for 30,000 miles @ up to 50 psi boost before I finally split the block. But never had a headgasket leak. Also, if you look closely, you will find that there are 8 studs that are slightly shorter then the rest. These need to go by the injector cups so the hold downs will clear the stud when you install your injectors. I learned the hard way by installing the studs with the motor out, installed the motor, then the injectors and the the hold downs didn't fit. :doh: Then I had to find the 8 special studs with motor already installed and play musical studs what a PITA that was!!
Bring the studs up evenly... 65, 85, 105, 125, (I go 140)
Then, do each stud one at a time... at your final torque (again, some say 125 others say 140)... Torque, Untorque, Torque, Untorque, Torque, Untorque, Final Torque
Use whatever torque spec you are comfortable with. I use 140 all the time and I have never had a failure. Others have said that they broke studs at 125 :shrug:
The directions call for 125 max ft-lbs. If you go more ARP won't warranty them if they stretch out. I went to 140 on my studs
As far as staging goes. This is what ARP said to do. First install all of them per factory spec at 95 ft-lbs. Then go straight to 125 then loosen and tighten back to 125 three times. Then go over all the studs one more time to ensure they are all the same.
You start with the outer part (exhaust manifold side) of the head and work towards the inside in rows.
The reason behind the repeated tightening and loosening during initial stud installation is that the friction between the male and female threads burnishes (polishes) the contact area of the threads. This polishing leads to a more uniform friction from stud to stud, which in turn gives a more uniform clamping force across the cylinder head.
This is procedure is not necessary if you are re-using a set of studs.
The type of lube you use will make a big differance. I originally used the moly lube when installing the motor and the TQ sequence was nice and smooth. with the motor oil I had some popping which indicates a build up of friction, not tension(clamping force). If you use motor oil I would go with the 140. if you use the Super lube, do not go beyond 120.
After reading all these posts, I still don't know which final tq number I’d feel comfortable with. The spectrum is from 120-140.... sure would hate to find out the hard way that I used too much or too little. What to do?
i seen where earlier in the post someone asked about balancing the engine when switching from pmr to forged rods, from what ive experianced the only time you realy need to worry about balancing the rotating assbly is when you are planning to be pulling very high rpms, or loads of power, balancing might give you a slightly smoother idle but it is deffinatly not required for hp numbers under 450 , ive never had any problems with any of the small block chevys ive built and i take them to 7000 rpms and 500 hp.
ya i switched from pmrs to forged rods in my 7.3 bout 2000 miles ago, mine runs great no vibrations or and adverse affects, ive been building engines for a while but this was my first deisel it turned out great. it idles smooth as stock and runs like a raped ape. since these things dont go 6 or 7000 rpms ever. Youll find that iff you just take the individual new rods and weigh them and make sure they all weight the same by taking off material of the heaveier ones that gets you close enough.
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