ARP Stud gave up

WWDiesel · **Posted:** Mon Aug 07, 2017 10:32 am

A torque wrench is simply measuring the mechanical resistance of whatever it is trying to turn be it fine thread, coarse thread, bolt, nut, etc..
The torque wrench is dumb, it does not know or care what it is turning and has no need to. It is simply measuring the mechanical force required to turn an object!

from wikipeda wrote:
*Torque, moment, or moment of force is rotational force. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object. Mathematically, torque is defined as the cross product of the vector by which the force's application point is offset relative to the fixed suspension point (distance vector) and the force vector, which tends to produce rotational motion.
Loosely speaking, torque is a measure of the turning force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque (turning force) that loosens or tightens the nut or bolt.

The magnitude of torque depends on three quantities: the force applied, the length of the lever arm connecting the axis to the point of force application, and the angle between the force vector and the lever arm.

*some text from wikipedia

Different clamping forces between bolts, nuts, studs, course threads, fine threads, is another whole different matter.....

racertracer · **Posted:** Mon Aug 07, 2017 11:35 am

I just got off the phone with the same ARP tech that i spoke to previously.

He reiterated what I stated previously.

No lube should be applied below the washer.

Apply lube on top of the washer, under the nut and on some of the fine threads starting from above the top of the washer.

He did not respond to my question of the conflicting installation instructions that are included in the VW kit 204-4706, which is the same kit that we are using for our engine.

He did say that ARP does not make a kit for the VM Motori 2.8L engine as of yet.

WWDiesel · **Posted:** Mon Aug 07, 2017 1:08 pm

racertracer wrote:

He did say that ARP does not make a kit for the VM Motori 2.8L engine as of yet.

Wish they would! It would probably clear up a lot of the questions and unknowns about using their studs.... :roll:

racertracer · **Posted:** Mon Aug 07, 2017 2:44 pm

He also said to wipe the studs clean of their rust inhibitor coating prior to install.

Brake fluid would probably do the job.

Also, to clean the threads in the block, insert the stud in the thread and chase the threads up and down 2 to 3 times to clean them like a chaser tap would, vacuum or blow out the left over debris and install the stud using the Allen wrench. Install the bone dry washer on the top of bone dry metal head, lightly coat the top of washer with lube, coat bottom of the nut with lube and a little of the fine threads just above the washer. Then finger tighten the nut allowing it to rest on the top of the lubed washer. Drive the stud down below the top of the nut approx. 3 threads using the Allen wrench and begin the torque sequence in thirds resting 20 second or more between turns.

After the completion of the torque sequence, the top of the nut should be in alignment (approximately) with the top of the stud.

Until ARP develops a proper kit for our CRD, I for one am going to follow this techs advice..... sounds good to me.

OK. now let the debate begin.

WolverineFW · **Posted:** Mon Aug 07, 2017 3:32 pm

I would call and speak to someone else at ARP if you can. Play dumb and ask all your questions like you never talked with anyone there yet. See if you get the same answer.

I see it as a red flag that he would not address the conflicting instructions in their official literature. Is he some know it all that thinks he has better ideas than everyone else at the company? He may be incorrect.

Sent from my SM-N910W8 using Tapatalk

APC9199 · **Posted:** Mon Aug 07, 2017 5:17 pm

WolverineFW wrote:

I would call and speak to someone else at ARP if you can. Play dumb and ask all your questions like you never talked with anyone there yet. See if you get the same answer.

I see it as a red flag that he would not address the conflicting instructions in their official literature. Is he some know it all that thinks he has better ideas than everyone else at the company? He may be incorrect.

Sent from my SM-N910W8 using Tapatalk

I'm not a head-stud engineer (I AM an engineer, though!), but the instructions posted above make sense to me. The idea of the assembly lubricant is to provide a reduction in torque applied to the shank of the stud, and instead allow the force of the nut to "pull" on the shank without twisting it. Not only does twisting the shank reduce its strength, but it also gives the stud the ability to "unwind" over time and lose the applied force on the head. You don't want to apply lubricant to the block threads because it can decrease the pullout force of the threads and could potentially allow the stud to unwind over many thermal cycles. You also don't want to apply lubricant under the washer because it (the washer) acts as a sacrificial surface for the nut to twist against. Once again, if the washer started to spin it would allow torque through the shank of the stud and twisting would occur again. A small amount of lubricant on the open-threads will allow the nut to turn freely up to full torque without twisting.

I'm no pro at this, but what he said seems to make sense.

TKB4 · **Posted:** Mon Aug 07, 2017 8:02 pm

Yes it does make sense to me also but they definitely need a better instruction writer and need a bold print warning not to put lubricant on the coarse threads at all. No one should have to call them to get clarification.

I still do wonder about the 125ftlbs answer though . That would probably work fine but the factory presumably wanted less torque on the outside bolts than the inside ones and putting 125ftlbs on all is definitely not doing that. I still think one of the engineers there said 130 and 120 but i wouldn't argue with 125 and 115 or 120 but i have absolutely nothing else to base it on. For now I will use 130 and 120.

I have also seen recommendations to use copper coate on all four surfaces involved. I have not used, it and the reason I didnt is I have not seen leakage between cylinders even though I know others have . I believe most of them leak through the layers of the head gasket due to the liftoff of the head from the block allowed by the stretched head bolts, allowing the coolant between the layers of the head gasket. I don't think it hurts anything and certainly think it could help at least on both sides of gasket I didnt have any handy at the time and asked a couple of certified diesel mechanics I know and they said it should be fine without it . Only time will tell. I would probably have used it had i had it handy at least on two surfaces but this would be essentially useless against leaking between the layers. I guess it might delay it starting some though.

flash7210 · **Posted:** Mon Aug 07, 2017 8:31 pm

I used Mopar gasket spray on my head gasket.
Basically, it's just red sticky stuff.

You shouldn't have to spray a MLS gasket with anything. It should already have the necessary sealing compound applied to it. But sometimes a little extra stuff adds piece of mind.

I've read about some guys reusing their MLS gaskets. They drill out the rivets, separate each layer, and get them perfectly clean. Then they spray each layer with copper coat and reassemble.
IDK how well it works but these were for engines where new head gaskets were very hard to find.

GordnadoCRD · **Posted:** Mon Aug 07, 2017 8:52 pm

flash7210 wrote:

Regarding fine thread vs coarse thread torque values...

I can see how a fine thread will achieve the same clamping force with less input torque.
But I think that the difference between the two is relatively small.
I think the most important aspect of fine threads is this:

Quote:

Fine threads because of their finer pitch allow for finer adjustments in those applications that need this characteristic.

Which translates into a more evenly distributed clamping force across the entire head.

Lubrication of the threads is also important.
Whether it be a bolt or a nut on a stud, the force to be overcome when torquing is friction.
As it tightens, friction increases. That is not the only force, there is also the force in form of work being done.
Conceivably, a oil of infinite lubricity could allow a bolt/nut to be tightened to the point of breaking before the prescribed torque value is achieved.

Not exactly. The torque applied to a threaded stud with infinite lubricity, is exerting work in the form of applying tensile force to the stud-nut or bolt, as well as compressive force to the head.
As such, if there were indeed infinite lubricity, as soon as you removed the torque wrench, the nut/bolt would immediately come unwound until there existed no more force applied AND the energy of momentum dissipated.
Why? Because threads = slope. Roll a ball bearing up a slide and let go. Same thing.

I'm not an engineer, but I have more than a passing acquaintance with physics. :dizzy:

flash7210 · **Posted:** Mon Aug 07, 2017 9:36 pm

No argument there.
Consequently, the ratcheting mechanism of the torque wrench wouldn't work either.
I was just trying to point out a unrealistic scenario where a theoretical lubricant would allow someone to keep turning the nut/bolt until it breaks with minimal effort (torque).

The force of work being done is applied by your arm through a lever (the wrench).

GordnadoCRD · **Posted:** Mon Aug 07, 2017 10:05 pm

Exactly.
Lubrication significantly increases the efficiency of the work transfer.
Friction adds to the work, holds the mechanism in place between applications of work, and the entire assembly in place, when work is complete.
The energy of the work, less friction, is stored as clamping force.
There is frequently a safety factor involving the risk of the clamping mechanism coming unwound, and many contraptions to nullify it.
NylaNuts
Stud/Nut combinations
Castle Nut / Cotter pin combinations
Safety Wire
Multi-angle or interference-cut threads.
Chemical thread-locking compound..
etc.

WolverineFW · **Posted:** Tue Aug 08, 2017 12:43 am

Sure they make sense but they directly contradict the supplied instructions. Why the discrepancy and why did he avoid the question?

I have seen lots of erroneous information in published instructions so it is very possible, but you would think they would have corrected that by now if they are so blatantly wrong.

APC9199 wrote:

WolverineFW wrote:

I would call and speak to someone else at ARP if you can. Play dumb and ask all your questions like you never talked with anyone there yet. See if you get the same answer.

I see it as a red flag that he would not address the conflicting instructions in their official literature. Is he some know it all that thinks he has better ideas than everyone else at the company? He may be incorrect.

Sent from my SM-N910W8 using Tapatalk

I'm not a head-stud engineer (I AM an engineer, though!), but the instructions posted above make sense to me. The idea of the assembly lubricant is to provide a reduction in torque applied to the shank of the stud, and instead allow the force of the nut to "pull" on the shank without twisting it. Not only does twisting the shank reduce its strength, but it also gives the stud the ability to "unwind" over time and lose the applied force on the head. You don't want to apply lubricant to the block threads because it can decrease the pullout force of the threads and could potentially allow the stud to unwind over many thermal cycles. You also don't want to apply lubricant under the washer because it (the washer) acts as a sacrificial surface for the nut to twist against. Once again, if the washer started to spin it would allow torque through the shank of the stud and twisting would occur again. A small amount of lubricant on the open-threads will allow the nut to turn freely up to full torque without twisting.

I'm no pro at this, but what he said seems to make sense.

Sent from my SM-N910W8 using Tapatalk

racertracer · **Posted:** Thu Aug 10, 2017 9:09 pm

https://ibb.co/meurra

Parts are starting to arrive.

Almost new short block going in this weekend.

Dent · **Joined:** Sat Aug 04, 2012 11:05 pm **Posts:** 275

See my PM. If you want to know if the stud was defective, the heat treatment was compromised, or if the failure was due to overtightening, contact me. Also, don't put the two pieces of the stud back together if you haven't already. You will cause microscopic damage to the fracture surface, which could impede an investigation. Keep the pieces from corroding too.

racertracer · **Posted:** Fri Aug 11, 2017 5:43 am

Dent, the top of the stud that remained in the head had to be extracted by using a drill bit and an extractor. Do you still want the stud?

Dent · **Joined:** Sat Aug 04, 2012 11:05 pm **Posts:** 275

That part won't do much good, but the part that broke and was not drilled will be very telling.

racertracer · **Posted:** Sat Aug 12, 2017 4:51 pm

Dent,

PM me the address of where you want me to send it.

racertracer · **Posted:** Sat Aug 12, 2017 5:53 pm

Using the old TTY bolts to chase the threads

Getting ready to put the block back in.

DieselJeepLuvr · **Posted:** Sun Aug 13, 2017 12:38 am

So I have to throw something in here. I'm not an engineer or an ARB tech but I've been building engines both race and diesel since the 80's and one of the most important things you can do during an install is to be VERY careful during a torque sequence. Because you stated that it was the first stud torqued during sequence, it'd doesn't surprise me that is the one that failed. Leverage will put a tremendous amount of pressure on bolts/studs if the sequence is not consistent and gradual. That's why race engines are bored with a torque plate installed because simply the process of torquing a head on will "warp" the bores of a cast iron block. How I was taught and have always done since without fail is hand tighten every bolt, then use a 3/8" drive ratchet wrench to and snug each bolt/stud in proper sequence, then use the same wrench to apply adequate force to tighten them (as if it were a 1/4" bolt). NOW get the torque wrench out. If it calls for 120 then start with 30 ft/lbs, then 60, then 90, then 120. Now I count 6-7 incremental steps to full torque. A retired diesel mechanic once told me that is the best way to build an engine (my dad).

racertracer · **Posted:** Sun Aug 13, 2017 2:38 am

DieselJeepLuvr wrote:

So I have to throw something in here. I'm not an engineer or an ARB tech but I've been building engines both race and diesel since the 80's and one of the most important things you can do during an install is to be VERY careful during a torque sequence. Because you stated that it was the first stud torqued during sequence, it'd doesn't surprise me that is the one that failed. Leverage will put a tremendous amount of pressure on bolts/studs if the sequence is not consistent and gradual. That's why race engines are bored with a torque plate installed because simply the process of torquing a head on will "warp" the bores of a cast iron block. How I was taught and have always done since without fail is hand tighten every bolt, then use a 3/8" drive ratchet wrench to and snug each bolt/stud in proper sequence, then use the same wrench to apply adequate force to tighten them (as if it were a 1/4" bolt). NOW get the torque wrench out. If it calls for 120 then start with 30 ft/lbs, then 60, then 90, then 120. Now I count 6-7 incremental steps to full torque. A retired diesel mechanic once told me that is the best way to build an engine (my dad).

Sounds good, I will follow dad's advice.

ARP Stud gave up

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