Better Headstuds

[Jetpilot]

Who would be interested (I mean really willing to purchase within the next 60 days) a much better headstud? I am talking about one that is 12mm so that it will fit our blocks with no issues and is made of better material... . Something that we can consistantly torque to 160+ lbs!



Now the question is what would you be willing to pay... . I may have a line on this product but it looks like the studs will go for $700-$800, if I can get enough orders I may be able to get them for around $600 a set. This would be for the 12v, 24v, and CR guys.



Let me know what you think.



Doug Smith

 

[RacinDuallie]

Doug,
As per our phone conversation on this- I'm in... ... Oo.

Arp recommends we torque the one's out now to what- 90 ft lbs. ? And we're taking em to 125 and wondering why the buggers are snapping? Yes I'm in this one Doug...

sounds like its "the stud" to run for the o-ring crowd.


















Keep in mind guys, the more people that come on this wagon the lower the pricing... ... .

 

[Forrest Nearing]

I'm in, but I want to know specifics before handing over the bread... namely, who's making them. feel free to contact me privately.



I'm ready to pull the trigger ASAP, but I could probably hold out for a couple months. (no time to play w/ the truck lately!)

 

[justinp20012500]

Anyone worried with pull the threads out of the block?

 

[thekidfan]

I talked with Piers about this about a month ago it'll be a shame that I just didn't go with the 14mm's if your pricing quote ends up being right. Will follow this thread though.

 

[COMP461]

Doug sounds like the studs I have been working on with Mike at ARP , this are Austenitic , and will jump the tensile strength up to 288 ksi from the 220 ksi studs we now use. This will give us the clamping load of the bigger stud with out all the absolute crap that is involved with a 14 mm stud.



Keep in mind that if you don’t bore the block to at least . 5 mm over with a torque plate after installing a 14 mm stud, the combustion gases you retain in the chamber now go past the rings. Ring seal is critical in what we do, and if you use the bigger studs you distort the block in a different way. I use ARP and the clamping load is only one critical, combustion retainment. If you will use the right o ring procedures, meaning put the wire in accurately, paying attention to the height of the wire all the way around, and the right total height. RD you have first hand knowledge of this.



In a proper o-ring job the wire should not vary more then a . 001 from side to side, and from hole to hole. I do not believe that the BHJ tool was every intended to put wire in with this precision. In a gas application you can get by with the height of the wire varying a few thousands, because you are using a dead soft copper head gasket, with a receiver grove on the other surface. The pressures are not near as great as in Top alcohol dragster, and top fuel , but they really don’t have problems in kicking out head gaskets , some times they will kick off the head , with the top of the block attached , with the head gasket still intact. The proper way in to use a mill with a digital indicator tool.

 

[Jetpilot]

This stud looks like it will be built, although initially in very limited quantities. I will get more specs on material and pricing hopefully within the next 7 days. I will also be taking pre-orders for guys that want them..... The first run with no pre-orders will only be around 10-20 sets. So if anyone is really considering these please let me know so we can get the run quantity appropriate.



Doug Smith

 

[crawler]

Keep me updated Doug.



Thanks,

Wes

 

[csutton7]

Mr. Smith--you have my attn. . so keep me in the loop... ..... chris

 

[justinp20012500]

Anyone worried with pull the threads out of the block?

So any word on this comment Doug?



Didn't you pull a set of 12mm studs out of the block?

 

[Jetpilot]

No I didn't pull any studs out of a block... ... At least not by tightening studs, I have seen deformed threads in a 24v motor but for other reasons.

 

[JGheen]

I would be worried about pulling threads out of the block with 160+ft. lbs of torque on studs that have even more tensile strength than ARP's or Haisley's, but I guess that will be found out when someone gets a hold of these.



Joe

 

[Diesel Freak]

I believe you will strip the threads on the nut before you pull the stud out of the block

 

[fest3er]

I would be worried about pulling threads out of the block with 160+ft. lbs of torque on studs that have even more tensile strength than ARP's or Haisley's, but I guess that will be found out when someone gets a hold of these.



Joe

Hmmm. Some rough calculations:

• the circumference of the stud at the inner diameter of the threads is about 11mm
• the circumference of the block's threads at the outer diameter of the threads is about 13mm
• assume 1" of stud threaded into the block

This should work out to about 1. 3 sq. in of shear area on the bolt and about 1. 6 sq. in of shear area on the block. Assuming your target clamp load is around 10000 pounds, the threads should be under about 3500 PSI shear load; call it 1600 PSI on the block and 1900 PSI on the stud. That should be easily within the limits of each material.



The real problem is the 4-6" of stud between the block and the top of the head. 10,000 lbs. clamp load on a 12mm stud works out to about 57,000 PSI (10000/(pi x r^2). That is close to the limit of a grade 2 bolt.



Now, extrapolating from the N14 (last reference below is a test report) peak cylinder pressures, 6B race engines could be seeing 6000 PSI peak pressures. This works out to about 75,000 pounds of force pushing up against the head bolts for a cylinder. Target clamp load for each bolt might then be about 20000 lbs. , which works out to around 120K PSI tensile for a 12mm bolt, which is the limit of grade 5 material.



Determining your actual, secret numbers is left as an exercise for y'all.



A few interesting web references:

http://www.zerofast.com/torque.htm

http://www.coastfab.com/boltsseries.html

http://www.anvilfire.com/FAQs/cast_iron.htm

http://raskcycle.com/techtip/webdoc14.html

http://www.biodiesel.org/resources/reportsdatabase/reports/tra/19950801_tra-020.pdf



N

 

[Diesel Freak]

Hmmm. Some rough calculations:

• the circumference of the stud at the inner diameter of the threads is about 11mm
• the circumference of the block's threads at the outer diameter of the threads is about 13mm
• assume 1" of stud threaded into the block

This should work out to about 1. 3 sq. in of shear area on the bolt and about 1. 6 sq. in of shear area on the block. Assuming your target clamp load is around 10000 pounds, the threads should be under about 3500 PSI shear load; call it 1600 PSI on the block and 1900 PSI on the stud. That should be easily within the limits of each material.



The real problem is the 4-6" of stud between the block and the top of the head. 10,000 lbs. clamp load on a 12mm stud works out to about 57,000 PSI (10000/(pi x r^2). That is close to the limit of a grade 2 bolt.



Now, extrapolating from the N14 (last reference below is a test report) peak cylinder pressures, 6B race engines could be seeing 6000 PSI peak pressures. This works out to about 75,000 pounds of force pushing up against the head bolts for a cylinder. Target clamp load for each bolt might then be about 20000 lbs. , which works out to around 120K PSI tensile for a 12mm bolt, which is the limit of grade 5 material.



Determining your actual, secret numbers is left as an exercise for y'all.



A few interesting web references:

http://www.zerofast.com/torque.htm

http://www.coastfab.com/boltsseries.html

http://www.anvilfire.com/FAQs/cast_iron.htm

http://raskcycle.com/techtip/webdoc14.html

http://www.biodiesel.org/resources/reportsdatabase/reports/tra/19950801_tra-020.pdf



N

heh heh :-laf

 

[Diesel Freak]

Austenitic

hmmm not a huge fan of Austenitic steels in a fastener application!!!



better make sure you use plenty of lube... once you gall a stud and nut... :{

 

[JGheen]

Well, one heck of an informative explaination there. I guess that they should be ok then @ that amount of torque, but I wonder why others have broke ARP studs @ only 125 ft. lbs? I believe the ARP studs are pretty much a grade 8 material or better?



Joe

 

[fest3er]

Well, one heck of an informative explaination there. I guess that they should be ok then @ that amount of torque, but I wonder why others have broke ARP studs @ only 125 ft. lbs? I believe the ARP studs are pretty much a grade 8 material or better?



Joe

They might've lubed the studs before installing them. Lubing significantly reduces the amount of torque needed to reach the desired clamping force.



In theory, the torque applied should slightly stretch the bolts or studs. I'll guess that the tension on the stud should be half-way to its yield point. (Beyond the yield point, plastic deformation and hardening occurs; before the yield point, elastic deformation occurs, from which the stud can recover and return to its original dimensions. )



N

 

[RacinDuallie]

Hey Doug-

What's the word on these new head studs?

 

[Jetpilot]

Still waiting on ARP..... They are still saying a very limited run but if they go as small as they are telling me I think they are all gone. I have asked that they run be larger, I will let you know what they say.