Engine/Transmission (1998.5 - 2002) ARP Head Studs.

[Harlacher]

I am going to put BD twin turbos on my truck and plan on keeping the OEM head gasket with APR head studs.



I am going to replace them one at a time and torque each one up to the stock torque then take them up five pounds at at time in sequence to 122 ft/lbs.



My question is about the re-torque, why should I un-torque each bolt then re-torque it to 122 ft/lbs? That is what it appears everyone is doing but I do not understand why. What do I gain? It would seem if I un-torqued the bolt to re-torque it I am adding another flexing un-flexing of the head gasket. I can see why I would want to check and re-torque if necessary but can't understand the un-torquing of the stud.



What do you gain if you un-torque and then re-torque instead of just re-torquing?



I will be keeping my boost under 50 PSI.

 

[JohnBoy5]

i am about to be doing the exact same thing. i am getting the tow twins. if anyone that has done this or has experience doing this please shed some light on this. i have had a battle in my head about weather to pull the head off and have it o-ringed ot run the twins. i how ever want to let them run up to what ever psi they will make. everything i am reading about the tow twins is fix the waste gate closed and control boost with a programs such as my quadzilla. i was just going to let it loose and see what she can do. i think another part of the real question is how much boost can you safely run doing the studs like this?

 

[WCPoe]

I believe the reasoning for the untorque or loosen is that when you do the retorque you won't get a false reading because of the "break-away" torque. If you just try to add more torque it won't do anything to a fastener that's already torqued because it has taken "a set" and basically won't budge until an excessive amount of torque gets it to break away and move. I don't know if I'm explaining this right but the principle is well practiced.

 

[Harlacher]

Makes sense, I guess I will do it that way for the first heating up and just check it the second time. That sounds like what most people who have successfully done it do.

I hope I am not missing anything. I do not see any reason to change a head gasket that has been working great up to this point, with 200,000 miles on the truck. Sounds like the key is keeping boost in the low 50s. I will operate in the range of 45 to 50. Can't wait to get the BD twins on. Should be here the first of this week. Doing the studs first then the twins. I have a BD intercooler on back order. Want a good driver that can pull a 10 thousand pound trailer. (maybe a run or two at the 1/4 mile)

 

[Harlacher]

Put the ARP head studs in, first torque was to 100, had to do it that way to get up to the old head bolt torque which I checked before starting, then went up to 122 in five pound increments. Got it hot and let it cool down, pulled it apart again and checked the torque on each one, found one that had loosened up or I had missed. One by one I un-torgued and re torqued to 122. Ran it for a while checked the ones I could without pulling off the rocker arms. I did not find any loose so I went with it. I have about 1,000 miles on it now, took the boost up to 50 pis I few times with no issues. I hope it will hold when we start running it on the track. I want to get it dynoed but I am still waiting for my charge air cooler to arrive. With the edge set at three I cannot keep the back wheels from spinning, the BD twins are amazing, I jump to 40 pounds of boost just feathering the throttle. People think I am flooring it when I am driving normal. Cruise is useless, it throws you back in your seat each time it speeds up. I have to get the waste gate set right, I am using the edge right now, it defuels at 50 PSI of boost. I am sure there is a lot more left. I don't think it is going to be easy to set the waste gate, the twins do not give you a lot of room to work.

 

[JohnBoy5]

how high can you take the boost with a setup like this?

 

[Harlacher]

I don't know how high it will go, I am limiting it to 50 pounds because I have stock head gaskets. I know it will go much higher. It jumps to fifty real easy. I have read threads on this site that say even with the ARP head studs not to go over fifty. "Still" waiting for my BD inter cooler... ... .....

 

[AWeaver]

hey guys... i just installed a set of studs and was wondering if you had any trouble getting your studs all the way down in the block holes? I had hell getting some of them to bottom out and some were still a little higher than others. Thanks in advance.

 

[Bill Weber]

Installed a set of ARP's in Sept. Removed 1 bolt at a time and installed the ARP's to 125#s. Ran it a few days & rechecked = OK. Most of the drivers side bolts had oil in them when I removed them - it DID NOT leak in as I removed them???? This oil must have been there from manufacture as only the bottom of the bolts showed any oil.

When I tried to install the 1st stud I couldn't get it in all the way. Saw oil on the bottom of the removed bolt. Carefully stuck a piece of oil absorbent pad into the bolt hole to remove the oil. A few I had to do 3x. to get it all. Then installed the studs with no problem.

Haven't pushed it all out yet but it has seen 45# on my set up.



Bill

 

[AWeaver]

ok thanks, I kind of figured that might be the culprit. I will run it like it is for a few days and check torque. I guess I can remove the higher ones one @ a time and re-torque w/ no problems?

 

[JJPage]

I am going to put BD twin turbos on my truck and plan on keeping the OEM head gasket with APR head studs.



I am going to replace them one at a time and torque each one up to the stock torque then take them up five pounds at at time in sequence to 122 ft/lbs.



My question is about the re-torque, why should I un-torque each bolt then re-torque it to 122 ft/lbs? That is what it appears everyone is doing but I do not understand why. What do I gain? It would seem if I un-torqued the bolt to re-torque it I am adding another flexing un-flexing of the head gasket. I can see why I would want to check and re-torque if necessary but can't understand the un-torquing of the stud.



What do you gain if you un-torque and then re-torque instead of just re-torquing?



I will be keeping my boost under 50 PSI.

I know you already did this... so this is after the fact. I am going to install studs in the future and I wanted to know the correct procedure also.



When I installed my R700's, Piers Harry sent me an email stating that if I kept my egt's below 1200*, he said no worries, no matter the boost with stock headbolts and gasket, block the wastegate on the secondary and run it...



I did not block the wastegate, but I do manage my egt's, I hit 50/60#s boost and my headgasket is still holding. I will still do the studs, and the following link I pulled from CompD answers a group of questions that I had.

ARP 425's who has the right way to install? - Competition Diesel. Com - Bringing The BEST Together



Jess

 

[Harlacher]

I blew out each hole with compressed air, was a little messy but I held a rag over each one. I also used a bottoming tap to clean up the threads so each bolt went down all the way. If you do a search you will find that most people who kept boost below 50 lbs did not have any problems, those going over did. That is why I stay below 50.

 

[JJPage]

I thought the instructions state, not to run the studs all the way to the bottom?

EDIT:Re-read, do not torque the studs in.

 

[Harlacher]

You are right, I backed each one back out one half a turn and then held them there with the allen head top. Pretty easy to do really. I have had no problems with them yet. I have to work on getting my waste gate to open at 50 PSI +/- a couple of pounds.

 

[JohnBoy5]

does anyone know if any of the studs come in contact with a water jacket?

 

[Harlacher]

Oh yes, make sure the tap is a bottoming tap.