ARP Head Studs

[martx-5]

I'm finishing up the TR3 engine, and have installed new ARP head studs. The OE torque recomendation is 100-105 lb/ft. ARP suggests to use 90 lb/ft when using their assembly lubricant based on 75% of the fasteners yeild strength for this size stud. OK, no problem, the stud kit comes with their lubricant. However they say that if you are using 30 wt motor oil as a thread lubricant, torque to 130 ft/lbs.

Astonishing that a different thread lubricant has that much affect on how tight the nut is! I went on their site to see why there is so much of a difference, but the blurb was just about friction. Does friction suck up that much torque when tightening a nut??

 

[DougF]

Could it be that 30 wt. squeezes out at high torque? Their lubricant could be a moly base that is made for high loads.

 

[Brosky]

Art,

The ARP studs come with their own installation lubricant and special (five), yes (five) times retorquing process. Please make sure that you do not use engine oil with these studs.

 

[martx-5]

I'll be using their lube, as it comes with the studs. The instructions didn't mention about the five times torque down procedure, but noticed it when I went on their web site. What's up with that, and why wasn't it mentioned in the instruction sheet that came with the studs??

 

[Guest]

Ditto. No 5-time torquing mentioned to me either.

 

[Brosky]

I've got to find that previous thread when I did my head. They have a set procedure of torque down, backing off and retorquing that they say must be followed.

There were others at the time who were familiar with it. Tom had to do the same thing with his TR6 engine.

 

[PeterK]

Below is a link of Triumph head stud fitting instructions from APTFast.com

https://www.aptfast.com/ARP_Additional_Stuff/ARP_notes_info/Triumph_HS_Kits.htm

 

[Brosky]

Peter,

That is similar, but does not match the instructions that I got with my kit. I didn't even get them open, when Tom or someone mentioned the procedure with five steps of torquing.

I'll find it sooner or later.

 

[Guest]

There seems to be a big difference between screwing down the nut "snugly" and torquing it down. These instructions don't even talk about a re-torque after the engine has been run. I installed mine with similar actions, torqued down to specified numbers, ran the engine a few hours, pulled the valve train and re-torqued.

Seems to be some confusion.

I did use their lube too. Even tapped the block.

 

[Brosky]

This is not after the engine has been run, Bill. It's on the install installation.

 

[tomshobby]

I found it for you Paul and sent a PM with the link to the information. Rather than add to the confusion I will let you handle it. It was not me that mentioned it but, you are right and it applies to different methods of reaching the correct torque. Whether using a torque wrench, the torque angle method, or a stretch gage.

 

[Brosky]

Art,

Page 40 of the latest catalog describes the recommended installation method for the ARP head studs, which does differ slightly from the instructions that we had last year. With that being said, proceed as you will.

 

[martx-5]

OK, I called the ARP tech guy and inquired about the 5x re-torque procedure. I also asked him why it wasn't mentioned in the instructions I got with the stud kit. Never got an answer to that question.

Anyway, after a bunch of techno burble, he said that re-torqueing (sp?) lowers the friction on the bolts/nuts and a truer pre-load results. He also gave the indication that five times wasn't really neccessary...two or three would most likely do it. The procedure is to loosen all the nuts in reverse sequence of tightening, and the bring back up to torque. He also mentioned to re-torque after the first heat cylce, but NOT to loosen...just check that it's up to snuff.

I'm begining to think that this is more smoke and mirrors then science. I'll follow their procedure and torque recommedations, but I'm not going to get anal over this.

 

[Guest]

I'm with you.

 

[PeterK]

I think that it's a standard procedure when re-torquing to first back off the nut a flat before applying torque to it. But of course, not loosen it.

 

[Brosky]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]OK, I called the ARP tech guy and inquired about the 5x re-torque procedure. I also asked him why it wasn't mentioned in the instructions I got with the stud kit. Never got an answer to that question. [/QUOTE]

Art, I don't doubt you one bit, but it's pretty confusing when I got an entirely different answer from ARP five months ago. I guess that the three is probably good to follow now and that's why I will do on the new engine.

I'm glad that you posted this as that really is a pain in the butt to do over and over if it's not really going to make a difference.

 

[TRED]

I agree, the torque to overcome friction is important.
I just did the heads on my engine and used arp studs and arp lube. I backed off at least a flat before doing the final torque. The type of head gasket and the planned use of the engine really determines if a retorque is needed.

I think that it's a standard procedure when re-torquing to first back off the nut a flat before applying torque to it. But of course, not loosen it.

 

[Brosky]

Tred,

What gasket did you use? I used the Payem, which I liked very much.

 

[TRED]

I used a Cometic but my engine is a Pontiac and has already seen 19 PSI of boost. I have always retorqued heads on nitrous and now turbo's, but the Cometic's didn't need to be retorqued.

Tred,

What gasket did you use? I used the Payem, which I liked very much.

 

[TR3driver]

Silly question ... seems like everyone is assuming that all studs are the same when it comes to installation; but I note that the referenced web page does NOT mention the TR2-4 motor; while being very specific about which Triumphs it does apply to. Might it be that they actually have different instructions for different installations ?

Not sure _why_ they might be different; but I note that ARP's web site talks about undercutting 'short' studs, and the TRactor motor has two very different lengths of head studs while AFAIK all of the mentioned motors do not...