Retorqueing with ARP head STuds

[RSP]

On retorques, Should I follow the procedure in the book or do it in a straight line or 1st two then next two then next two and so on? Whats the best way? I am on the second Retorque and I am at 122lbs, Should I go more on the next one or is 122 the limit? I am useing a Lube that came with my Power Stroke A-1 studs, It seems to work real well.

 

[CumminsPower98]

I do mine in a line when I'm retorquing once they are up to spec. I maxed out at 125 with the ARP molly lube. So far I have done three retorques. If you are increasing the torque then you need to follow the book sequence. I personally wouldn't go past 125 and that's probably pushing it when using the molly. I also remove each nut and washer and relube all surfaces to insure an accurate torque.

 

[Vaughn MacKenzie]

When you are going through the retorquing sequence, would changes in valve lash serve as an indicator as to whether you're still compressing the head gasket or not? I did one retorque on my '96 last weekend but it had nil effect on my valve lash. . . only had to touch up 2 valves and they were probably off anyway. By the way, I installed my resurfaced head and put in the new studs, did the initial torque, then drove 18,000 miles before doing the retorque procedure

Vaughn

 

[TJSHOTROD]

I take mine to 135.

 

[AMassaro]

125 with ARP's moly lube is what ARP recommends as I called them directly and talked to a tech guy there a few weeks ago. Retorqueing has more to do with friction and stretch of the studs than the head gasket itself. First time a stud is torqued, its friction is at its highest. After the third or so torque, the friction is at its lowest and you have the most accurate torque and clamping force as the stud has taken "set" and will not stretch any more. ARP recommended starting at center and working your way out in circular fashion. No need to remove washer and nut either. Moly is still there. They want you to spin nut one full turn loose before retorque. Three re-torques are all that is neccesary although he said you can go out to five if it makes you feel better. No need to go thru heating cycles either. Once that stud has taken set, it isn't going to stretch anymore. Period.

 

[CumminsPower98]

I don't totally agree about the head gasket being less of a factor. It does settle considerably as I have found. I also think the heat cycles have something to do with it breaking in. The valves will tighten up a lot in the first while and need a couple adjustments (stock bolts). I always go over my valves after every retorque on the studs of course. I have done a couple gaskets on a '97 using the same stock bolts each time and both times the valves tightened right up after it was run a few thousand miles. The last gasket I did on a '94 I adjusted the valves +. 002 to help make up for it some. I have not been back over it again yet. So are you saying to do all the retorques right up front before even starting the engine? I do understand what you are saying about the studs breaking in but it seems to me that the gasket also needs some break in time.



ARP must have changed their specs because the paper with my studs stated 90 using the molly and 125 using oil or was it 122?

 

[AMassaro]

I should have stated that what I was referencing was just changing over to studs, not doing a head gasket change. I'm sorry for that. The third gen trucks have an MLS gasket (multiple layer steel) that is holding up very well on it's own and is very stout with studs.
ARP did change their specs. I had been reading so many differing torq specs for studs that I had to do some research on my own. If you go on ARP's site they have a torque chart for all of their fasteners. And it states for a 12mm head stud to go to something like 96ft/lbs for ARP's moly and 126 for motor oil. Yet everything I read on these forums stated to use 126+ for the studs WITH the moly, which to me, meant over-torqueing by around 30% ARP's specs. So I made a phone call. The gentlemen I spoke with was very aware of our Cummins engine and he said the specs on the site were "generic" and didn't apply to the Cummins. He said the correct spec is 125ft/lbs with ARP lube and three torque sequences for doing a stud swap only. New head gaskets will require the heat cycling as mentioned before. Once again, sorry for the misunderstanding on my part. I spend too much time reading about 3rd gens and forgot this forum deals with all gens...

 

[CumminsPower98]

No problem, thanks for the research calling ARP and all, it's nice to know that is now their recommended torque. I just assumed you were talking about studs and a fresh gasket so I see your point now and I agree.