Did I just break an ARP main stud??

[mauromj]

Installed ARP main studs the other day using a classic beam style torque wrench. The torque spec listed in the instructions was 100lbs, so I went ahead and torqued them down (in sequence) in 20-40-60-80-100 increments.

In the 80-100lb process, one of the studs felt like it stretched and lost significant torque. This occurred at around 90lb mark and read ~70lb after that.

Has anyone had this happen? Any ideas what happened? Im really confused what the hell happened here and with it being a main fastener and all, I am somewhat concerned in running it.

[Nizmo]

Installed ARP main studs the other day using a classic beam style torque wrench. The torque spec listed in the instructions was 100lbs, so I went ahead and torqued them down (in sequence) in 20-40-60-80-100 increments.

In the 80-100lb process, one of the studs felt like it stretched and lost significant torque. This occurred at around 90lb mark and read ~70lb after that.

Has anyone had this happen? Any ideas what happened? Im really confused what the hell happened here and with it being a main fastener and all, I am somewhat concerned in running it.

So you busted the stud installing it or you where tightening the nut onto the stud when stretched?

Check for cracks, if none pull the stud and check for cracks. What type of tool where you using to install the studs?

[zillarob]

Not sounding good man.
People breaking the block with oem studs makes me think there is no reason to upgrade.

[mauromj]

So you busted the stud installing it or you where tightening the nut onto the stud when stretched?

Check for cracks, if none pull the stud and check for cracks. What type of tool where you using to install the studs?

I threaded the stud in by hand. The "stretch" occurred when I was torquing down the nut on the stud.

[mauromj]

Not sounding good man.
People breaking the block with oem studs makes me think there is no reason to upgrade.

This upgrade to the stud kit was not based off of strengthening the block.

I chose to go studs because oem one time use bolts are the same price as multi-use arp studs. That's all.

Anyways, back on topic.

I went ahead and bit the bullet and finished the tightening sequence. It is currently tightened all the way to 100lbs and seems to be holding fine.

I'm not sure if I should pull it out or just leave it and not worry about it.

What may have happened here was that the stud was hydrolocked. After tightening it to enough pressure, the liquid(or whatever was in the threads) made its way past the threads and caused that torque decrease spike. Does this sound possible to anyone? I'm trying to think positively here and believe everything is alright lol.

[mauromj]

Also, I see no cracks in the block around the stud area.

[zillarob]

People have cracked the block from too much hp/tq/bad timing/wtf ever while running the oem bolts.
Sounds like they are strong enough for the application and dont require any other work to use.

Whatever caused what you felt, you are pretty much screwed because you will never know for sure. Not a set of dice I would roll.

[mauromj]

People have cracked the block from too much hp/tq/bad timing/wtf ever while running the oem bolts.
Sounds like they are strong enough for the application and dont require any other work to use.

Whatever caused what you felt, you are pretty much screwed because you will never know for sure. Not a set of dice I would roll.

So I'm screwed? I should just throw my build away and start over? *insert rolls eyes emoji here*

Update:

Ended up pulling the stud. No signs of cracking on the stud itself.





When looking down the hole, I see a line (Assuming scratch? Hope not crack...) about half way down the main cap. I'm assuming it's a scratch since there's no really way a crack would occur there.



I'm at an awe guys!

[zillarob]

Its not a problem, they commonly lose 20ft/lb or so out of nowhere. Its just the arp lube kicking in.

[MacDaddy]

I would checK the threads on the block and if ok, re install and try again. Iirc arp has a recommended install torque for studs themselves before torquing them down. As you said yourself they are multi-use so may as well do it all over again to be safe.

[DieselElectric]

If the threads were damaged you would see material on the stud upon removal.

Did you take initial measurement on the stud? IIRC ARP recommends keeping record of stud lengths to record stretch from multiple uses. If you didn't measure, I would pull another one and compare. If all checks out, slap it back in and try again .

[aysix]

I would run it

[LightningLou]

As long as you use the ARP moly lube you should be good... Threads look fine

[mauromj]

Went ahead and installed the stud again and torqued it down to 100ft-lbs. No signs of what occurred previously.

I guess i'm good to go?

[Nizmo]

Went ahead and installed the stud again and torqued it down to 100ft-lbs. No signs of what occurred previously.

I guess i'm good to go?

You did the right thing here, pulling and checking.

Make sure you use some moly lube on the threads of the stud, should be stated in directions....

Without the lube you wont get accurate torque readings. I will assume you have already done this.

[zillarob]

Man, Id have a real tough time sleeping until I tore that thing far enough apart to figure out exactly what caused that.
Maybe all the way back down to the crank out if it.

Prob just hung up on the dowel or maybe just had to find its home, but Id sleep much better knowing what it was, or at least going back over everything.
There are quite a few curveballs these evil cars like to throw at us. Id def take that that main back off and be checking bearings and clearances just to be safe.

[Zba]

Based on the mark on the main cap it was probably the friction being overcome between the nut and the cap. I've had this happen although on a much smaller scale. If any of you have done cam covers on an air cooled 911 you know what I'm talking about.

[MacDaddy]

If the threads were damaged you would see material on the stud upon removal.

Not necessarily.

If in doubt, double check your work. It can save you a lot of time and money

[sxC]

Pull it out and put some more molly lube on it. Retorque. I think you'll be fine.

[mauromj]

In all honesty, I think I am going to pull them all out and take my block in to get line honed. This is something I never had done.

I have heard of people swearing by it and saying it needs to be done when studs are installed, and others saying its not totally required.

Anyone not had a line hone done?

[landfill]

Bud DO NOT, I REPEAT, DO NOT torque your main studs to 100ft/lbs.
034 and the numbers you get from ARP are incorrect. There have been
multiple threads on here about this. Torque is in 3 sequences with your
final torque being 55-65ft/lbs if I remember correctly. Your final torque
should be exactly what it says in the Bentley manual. Also make sure
you use the moly grease on the threads and do not use any sort of loc-tite
or equivalent. If you have any other concerns feel free to ask here. I learned
a lot on my first 2.7. Also you are supposed to check your bearing clearances
with your caps torqued down just FYI.

[landfill]

A line hone is required if you do a block mod that throws
your main bearing bores out of alignment. On this particular
application there are only 3 scenarios that would require
a line hone.

1. Using main caps that were not assigned to your motor from the factory
2. Installing aftermarket billet main caps. These require fitting to the block
3. Abnormal crankshaft journal wear

If none of those apply your good to go. Certain car platforms do it just for
studs but ours do not require it.

Also that circle imprint on your main cap is from your arp
washer digging too far in from that incorrect 100ft/lbs.

[astondan4]

I torqued my main studs down to 100ft/lbs and had no issues. And I did that twice because i needed to checked the bearing clearances. It did seem high to me as well but everything went fine on my end. I did use a generous amount of the arp assembly lube on mine as well. Hope everything ends up being okay.

[blitz2190]

I didn't read all the comments, but this has happened to me before, if the hole is filled with liquid and you thread a bolt it compresses, liquid does not compress so it blows a micro Crack in the weakest point the block. Happened on the oil pan of my 1.8t but thankfully went to the outside. Not saying it happened but wouldn't hurt to blow air in there and see if it comes out somewhere else, if so use some ptfe pipe tape to seal the hole.

[DieselElectric]

Didn't even think about that, but now that you mention it, I was taught to always use air to blow out head bolt threads before reinstall. They almost always get oil or coolant in them upon removal.

Good thought.

[zillarob]

I could see that happening with bolts if doing a shitty job and not blowing out the holes, but op's motor looks clean enough that I would guess he is doing it right.
With studs, you are going to be tightening the nut so this shouldnt be a prob anyway.

[julex]

^^^ Which makes me question why the studs turned on its own volition while torquing the nut... unless OP is somehow torquing the STUDS themselves to 100lb into the block before nuts and that's what he describes now.... or the part in the block was lubricated significantly better than the nut and that resulted in the stud spinning with the nut at the end of torque sequence and the friction at nut was much higher than at stud to block...

For that reason, you should only lubricate the studs very lightly if at all where they go into the block. You want these threads to hold tight once the bolt gets its tension in at the time of torquing the nut down and friction coefficient is high in that area... this is because studs should not transmit any significant amount of torque to block threading as it will cause cracks and thread damage if it was allowed to (there is no hard stop on the studs, just end of thread that will inevitably destroy threading in the hole you're trying to torque stud into with any significant amount of torque).

The stud should install with stud part going in "finger tight" plus couple of lb/ft to make sure it is tight in there and then MOLY (in engine) / anti-seize anywhere outside like wheels/manifolds etc lubricated nut on top! Installed that way it will not cause the stud to rotate into the threading any more than first finger tight installation (the nut pulling on stud and resulting friction between stud and material it sits in will stop it from tuning out)!

[landfill]

http://www.audizine.com/forum/showth...i-s4-2-7t-quot

The final torque of the main studs is 65 ft./lbs.

[sxC]

http://www.audizine.com/forum/showth...i-s4-2-7t-quot

The final torque of the main studs is 65 ft./lbs.

Adding to my earlier comment, I just looked at my notes from when I did my block. I followed the bentley sequence and torqued each stud first to 30 Nm then 60 Nm on the second pass. Then added 90 deg. Went back and double checked with a torque wrench that each was at least 65 ft-lb after reading some stuff online.

100 ft-lb does seem a little high. But if you can't see any thread damage and they still torque down after taking them out and putting them back in, then they should still work okay. Maybe you accidentally stretched the bolt a bit?

[zillarob]

60nm + 90deg is def more than 65ftlb with a non-stretch fastener, and wouldnt surprise me if it was more than even 100ftlb.

[landfill]

60 newton meters equals almost 45 ft/lbs.
With the 90 degree stretch you're at 65 ft/lbs.

[landfill]

https://jhmotorsports.com/shop/catal...gth-p-971.html

JH Motorsports also sells the Head Stud kits for this motor in addition to hardware for other Audi/VW motors. Please email us at [email protected] if you don't see hardware for your engine.
Note: Final torque specifications for this hardware is 65 foot pounds. These stud kits can be reused again and again, unlike factory hardware.

[Peter1.8t]

That would scare the fuck out of me.

[okkim]

I just asked from ARP that what is the correct torque for this set (ARP-204-5801), and they answered:

11mm studs torque to 100 ft lbs. Start at 35, then 70, and finish at 100. The side bolts torque to 20 directly. Make sure you use the ARP assembly lubricant when installing.

[julex]

That doesn't sound right... Anyhow, if this is of any weight here, Eurospec torque specs for their hardware is here:

http://www.eurospecsport.com/product...que-specs.html

It calls for 65lb/ft for 11mm non-stretch hardware. I've used the above and had zero issues for years now.

[MacDaddy]

Go with the hardware manufacturers (ARP) specifications, you can't willy nilly these things

[okkim]

I don't understand why it wouldn't be right, if they said that it is 100 ft/lb, why it wouldn't be? Raceware isn't ARP.

[julex]

But then you're threading this stud into grey iron block whose tensile strength is order of magnitude lower than uber-steel of ARP... It is not about how much can stud itself take, but what block can take without creating excessive stress in the block or outright ripping the threads out.

Even ARP bolt is stretching somewhat (everything stretches given enough force, ARP returns back to its shape due to the amount of force needed to permanently stretch it) so the first 8-10 spins of thread must be able to hold about 15,000lb of pre-load juding on what 100ft/lb on a bolt of that size/threading translates to... yikes. If there was a way to measure the main bolt stretch (like when you do at rods when using non-stretch bolts in there, however you usually thread into forged rods in that application with mating material being much stronger than case grey iron), you wouldn't go by TQ numbers but by stretch values.

Godspeed man.

[mauromj]

Time to pull out the set of dice I guess haha. So much conflicting information.

[zillarob]

I wouldnt sweat it too much.
Its nice to have mfg numbers to go by, but nothing is really carved in stone. There is a huge range that will work just fine.
I wouldnt be surprised if anywhere between 20ftlb + loctite to 100ftlb with secret sauce would run without any probs.

Personally, I would go with the spec that the block was designed and machined for.