ARP head stud concerns

[trik396]

ARP head stud concerns

--------------------------------------------------------------------------------

I have installed many studs in mains and heads on gassers in the past. I've read almost every thread here in reguards to torquing head studs down. And it seems every one I read is incorrect, at least to ARP's specs. First this is right off of ARP's site.

1. The friction factor changes from one application to the next. That is, the friction is at its highest value when the fastener is first tightened. Each additional time the fastener is torqued and loosened, this value gets smaller. Eventually the friction levels out and becomes constant for all following repetitions. Therefore, new fasteners should be tightened and loosened through several cycles before applying final torque. The number of times depends on the lubricant. For all situations where ARP lubricants are used, five cycles are required before final torquing.

2. The lubricant used is the main factor in determining friction, and therefore, the torque for a particular installation. Motor oil is a commonly used lubricant because of it’s ready availability. If less friction is desired in order to install the fasteners with less torque, special low friction lubricants are available. With special lubes, the required torque can be reduced as much as 20 to 30 percent. It is important to keep in mind that the reverse is also true. If the torque value has been specified for a particular fastener on the basis of low friction lube, installing the fastener with motor oil will result in insufficient preload; the torque has to be increased to compensate for the extra friction caused by the motor oil

Going to the fastener torque recommendations I find that the correct torque for a 12mm stud is as follows.
Using 30wt motor oil - 122ft./lbs

Using ARP's moly lube - 96ft./lbs

I think if the guys here and elsewhere that are using the 122ft/lb number AND using ARP's moly are really over tightening the fastener to a point of possible weakening the stud.
Can anyone here point me to a study that shows in our Cummins application that the studs should be torqued to 122ft./lbs using the moly lube? This is placing something around 30% more pre-load than ARP recommends for this fastener. I would think they should know the correct strength of their product.
If I am wrong, please do not hesitate to correct me. I will be studding the head soon.

Thanks
Tony
__________________

__________________
2005 DodgeRam2500 CTD/ 4x4/ BigHorn/ Autometer/AmsoilBypass/AemBruteforce
Trans by Goerend/ Walbro392custom fuel system/CAT2micfuelfilters/IISilver64/BanksIC
Projector HID's/DiablosportPredator/VanAaken3.2/QuadsXZT
617hp 1200+trq
KOREChasewFoxShox/Carli&FoxDualSteeringStabilizer/ NittoTerras285's
3 people can keep a secret if 2 of them are dead...

[trik396]

I just got off the phone with ARP. I talked to a very well informed technician named AL. He said the specs I was refering to were "generic" and do not apply to our Cummins.

The correct torque is 125ft/lbs with moly lube. He strongly recommends to install the studs finger tight only in the block using motor oil or moly. NEVER LOCTITE. Using loctite can totally screw up your torque measurements among other things. He suggests doing one stud at a time from center out. Once all are torqued to max, go back and loosen one at a time and go back to 125ft./lbs. Do this three times and you are done.

I stand corrected and I'm very glad I decided to call ARP directly.

__________________
2005 DodgeRam2500 CTD/ 4x4/ BigHorn/ Autometer/AmsoilBypass/AemBruteforce
Trans by Goerend/ Walbro392custom fuel system/CAT2micfuelfilters/IISilver64/BanksIC
Projector HID's/DiablosportPredator/VanAaken3.2/QuadsXZT
617hp 1200+trq
KOREChasewFoxShox/Carli&FoxDualSteeringStabilizer/ NittoTerras285's
3 people can keep a secret if 2 of them are dead...

[BBRam]

Nice job Tony . That is some great info. Sorry I didnt get here sooner. On the retorque, if the head gasket is not being replaced, just the stud's installed, I think 3 retorque's may be a little excessive. If the gasket has been replaced I agree with 3. But there should be heat cycle's done in bettween the retorque's.

__________________

03-3500, DRW, QC, 4x4, DTT Trans, Mag-Hytec, R700 BD Twins, BD IC Boots, BD Billet Flexplate, Lockup Switch, SMARTY TNT-R BETA/TS MP-8, Eliminator Fuel System, Floor It Stage 3.5 CP3, F1 Flux 3.8's, ARP Head Stud's, Springs, Fluidampr, ATS ARC-FLOW, AFE, Boost, Drive Pressure, Pyro, Fuel Pressure, Tran's Temp, Rail Pressure Gauge, GDP Ladder Bars, GR 7" Miters. Old #'s (R/T .021, 60' 1.76, 1/4 ET 13.14 @ 100.45 mph)

[trik396]

Head gasket is not being replaced... thankfully...

The three re-torques are for the reasons mentioned in number 1 above...

I know I've done re-torques on engines with aluminum heads due to the greater expansion of aluminum, never on iron, but I guess it couldn't hurt.

__________________
2005 DodgeRam2500 CTD/ 4x4/ BigHorn/ Autometer/AmsoilBypass/AemBruteforce
Trans by Goerend/ Walbro392custom fuel system/CAT2micfuelfilters/IISilver64/BanksIC
Projector HID's/DiablosportPredator/VanAaken3.2/QuadsXZT
617hp 1200+trq
KOREChasewFoxShox/Carli&FoxDualSteeringStabilizer/ NittoTerras285's
3 people can keep a secret if 2 of them are dead...

[Paccool]

Good info Tony.

You have a PM

__________________
Stan

93 D250, PDR Twins HX35&HT3B, 60+# boost,PDR stage 2 head w/o-rings, PDR Cam, modified VE Pump, piston style lift pump, modified 5" intake w/AFE, ATS ported manifold,DTT 89% converter, 4" RIP exhaust, modified tranny, EGT/boost/tranny/tach gauges, TPS removed, a little chrome under the hood. Mag-Hitec tranny and diff. covers. Rear sway bar. Line-x bed liner, after market seats. Front end rebuilt with new springs - 2 " taller now. Single stage Water/Meth system installed. Oversized intercooler installed 10/06, 3" IC lines.

"if you're not part of the solution, you're part of the problem"

[jaymo]

Good job Tony. This the info I received from What I believe is a reputable source. Just not ARP themselves.


Thanks for setting mymind at ease...Jay....

__________________
2000 2wd 5spd , TsT/ez stack , afe stg 1 , rips 5" ,
Fassed , con FE , Jammers stg5. Ported head ,Oringed and studded.Dynod 444/834 on may 12 07
UNION CARPENTER AND PROUD OF IT

[JMP'S PERFORMANCE]

Did ARP say to use new moly each time you break torque and retorque or just the first time?

Also I went 100 ft lbs first time ran the motor up to temp twice and drove it a little ways and then while it was still hot broke torque and retorqued to 115 ft lbs I have put on over 400 easy miles not going over 20 psi in a week and am going to break torque and retorque to 125 ft lbs tomorrow, then in about 1-2 weeks I will retorque again to 125lbs before towing a big heavy trailer a few hundred miles.

On my last retorque should I still break torque and retorque?

I have 0.020 head gasket, and o ringed head

Will I be fine running 43lbs of boost by that time or should I do one more retorque?

New Moly each time or just break torque and retorque?

Thanks,

__________________
96 Ram 2500 Cummins; #10 TST fuel plate, star wheel adj,17* timing, headstuds, 3k gsk washer, 0.020 Marine Headgasket,O ringed head, 5spd, South Bend clutch.
FARMBOYS DIESEL @ farmboysdiesel.com

[trik396]

Break free then torque one more time and your studs should be "set". The moly is there from the first time, no need to add any more.

__________________
2005 DodgeRam2500 CTD/ 4x4/ BigHorn/ Autometer/AmsoilBypass/AemBruteforce
Trans by Goerend/ Walbro392custom fuel system/CAT2micfuelfilters/IISilver64/BanksIC
Projector HID's/DiablosportPredator/VanAaken3.2/QuadsXZT
617hp 1200+trq
KOREChasewFoxShox/Carli&FoxDualSteeringStabilizer/ NittoTerras285's
3 people can keep a secret if 2 of them are dead...