My ARP Stud Failed!!

We drilled a hole down the center of the stud to get it out and it was soft (!!!) until we got down to the threaded portion. As I said before, the metal on the stud has swirl pattern in the it where it broke. I'll try to get a picture with the swirl marks as I'm convinced the stud was defective. We've installed >10 sets of studs and this one is the only one to fail?

A big thanks to Greg(COMP461) for calling Chris @ ARP and doing your part in getting me a new set of studs!
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You mean Enterprise Engine Performance said go fly a kite, it's a performance part? Who would have guessed? :hehe:
 
joefarmer said:
You mean Enterprise Engine Performance said go fly a kite, it's a performance part? Who would have guessed? :hehe:
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Well that sucks!
 
theres a small family owned shop in indiana that sales 12 and 14mm studs, but if bank$ is using arp they must be the best.
 
Did you use plenty of the lube on the studs?

Congrats to Greg(Comp461) on stepping up to replace the part that others neglected to do. :clap: :clap:

ARP makes the finest fasteners available, and I love my 'New Age 625's'
 
Yes plenty of lube was used -

What I would like to know is how long the stud was cracked and not doing its job but either way it wrecked my HG pretty bad

Lavon
 
I agree, ARP produces some of the best fasteners in the business. But every now and then, something seems to go wrong. The failures are small in number, but at the same time I never hear from anyone on a broken stock head bolt.

I cant think of around a half dozen ARP's that have broken. Pretty small number, but seems higher than it should be considering I dont work with many people on fastening projects anymore.
 
Soup Nazi said:
I agree, ARP produces some of the best fasteners in the business. But every now and then, something seems to go wrong. The failures are small in number, but at the same time I never hear from anyone on a broken stock head bolt.

I cant think of around a half dozen ARP's that have broken. Pretty small number, but seems higher than it should be considering I dont work with many people on fastening projects anymore.
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I am not a chemist or metallurgist (is that how it is spelled?) but I would think that is because the stock head bolts are softer and will stretch where the ARP's tend to break rather than stretch.
 
getblown5.9 said:
I am not a chemist or metallurgist (is that how it is spelled?) but I would think that is because the stock head bolts are softer and will stretch where the ARP's tend to break rather than stretch.
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Ding! You won a cookie!!:rockwoot:
 
It may just come down to only a handful of people actually doing retq's on their stock head bolts VS multiple retq's on the ARP's.

I like the ARP's and use them myself. There is better out there than the run of the mill ARP2000, but hardly anyone needs them.
 
Getting you a new set od studs, is just the kind of thing Greg would do. Good on ya Greg.

Here's my two cents. No two pieces of metal are exactly the same. Can you write your name 100 times and have every line come out looking exactly the same. Sometimes something goes wrong in the process while it's being made. They could have had a whole piece of metal that during the extrusion process got one air bubble in it, and you were unlucky enough to get the stud made from that piece with the air bubble.

At least you're getting a new set.
 
crewgirl said:
Getting you a new set od studs, is just the kind of thing Greg would do. Good on ya Greg.

Here's my two cents. No two pieces of metal are exactly the same. Can you write your name 100 times and have every line come out looking exactly the same. Sometimes something goes wrong in the process while it's being made. They could have had a whole piece of metal that during the extrusion process got one air bubble in it, and you were unlucky enough to get the stud made from that piece with the air bubble.

At least you're getting a new set.
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Thats exactly the kind of thing I am talking about. Every now and then, an ARP stud will snap. One of the ones I have here snapped at 100 ft lbs. In the early days of Cummins ARP studs we tested them to extreme levels and found them better than expected. Soon thereafter, the intermittent breakage started. Just one every now and again. No real way to pin down what was wrong other than quality control on the steel from the supplying mill.

On the same plane of thought though, I dont get reports of broken stock bolts from anyone. But like I said earlier, could just be the stock bolts never get the retq's and cycles the ARP's do.
 
crewgirl said:
Getting you a new set od studs, is just the kind of thing Greg would do. Good on ya Greg.

Here's my two cents. No two pieces of metal are exactly the same. Can you write your name 100 times and have every line come out looking exactly the same. Sometimes something goes wrong in the process while it's being made. They could have had a whole piece of metal that during the extrusion process got one air bubble in it, and you were unlucky enough to get the stud made from that piece with the air bubble.

At least you're getting a new set.
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Typically you won't get an "air bubble" in an extruded rod. Not saying it doesn't happen, but it is rare.
Couple of possible reasons for the failure...
1.Inclusions in the raw material. Sulfide stringers are an example of inclusions.
2. Over torqued stud. (not accusing, so don't be offended)
3. Defect from the machining or extruding process. This would be enhanced during the torquing of the stud.
4. Improper heat treat. In a batch environment the center stud of the basket may not have gotten to the proper temp.
5. Improper quench. ARP's at one time were hard to come by due to demand. Speed things up and the quench bath may have not been at the proper temp to quench the studs fast enough.

There may be other reasons I've missed but to correctly diagnose the failure the fracture would need to be examined in a SEM (electron microscope) tested for hardness and the microstructure would need to be looked at and compared to the print specification.

Glad ARP is stepping up to help you.
 
Of the list above I would say Improper Heat treat would be my guess. Being that I could drill very easily down the center with an1/8" dArill bit, but only for about 1/2 in. then bam... the bit stopped cutting. There was a distinct line in the stud where it went from soft...to HARD!

But remember...unsinkable ships sink... unbreakable studs break...:) its life... I'm used to it.

Lavon
 
LAmiller said:
Of the list above I would say Improper Heat treat would be my guess. Being that I could drill very easily down the center with an1/8" dArill bit, but only for about 1/2 in. then bam... the bit stopped cutting. There was a distinct line in the stud where it went from soft...to HARD!

But remember...unsinkable ships sink... unbreakable studs break...:) its life... I'm used to it.

Lavon
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Heat treat I bet.... My wheel studs on my Aerospace Brakes off of my SS car all broke when the weight of the car was put on them!!! Aerospace told me it was improper heat treating! Thank god I wasn't doing 130+mph! My studs had the swirl marks also and were soft.$.02
 
two things...

1. I've seen a broken stock head bolt... broke shortly after a re-torque

2. torque values are for a cold engine. if you're torquing at 122 hot, you're not getting as much clamping force as you would at 122 cold.
 
RacinDuallie said:
:umno: I am using them on one of my builds- Twinned-P-pumped-24Valve Engine.....:thankyou2:
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Last time I saw your engine it was on an engine stand. Did you even fire your engine up yet ??
 
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