ARP head studs

denis4x4

denis4x4

Well-known member
Picked up an ARP catalog at the GNRS and see that they have a head stud kit for the Model A with polished SS acorn nuts and washers. Part number is 151-4002.
 
Weird, I have a saved electronic copy of a 2017 catalog with it in it, and I have been looking at it online in their 2020 catalog for at least the last 2 weeks now. I saw it and pointed it out to a friend of mine.


*edit* I emailed Summit Racing to get pricing on the kit as I don't see it listed anywhere online.
 
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As the sud stiffness increases, the stress in the block threads increases, and fatigue life is adversely effected. Why do you need studs intended for high performance engines?
 
Bob Bidonde said:
As the sud stiffness increases,

> We are not concerned with stud stiffness, we are using them in tension and thread form shear.

the stress in the block threads increases,

> The stress on the block threads will remain the same as long as the torque value is the same and the thread form is the same.

and fatigue life is adversely effected.

Fatigue life of the BLOCK threads is NOT affected by changing the material the stud is made of. That changes ONLY with torque value, thread form and number of cycles the system goes through.

Why do you need studs intended for high performance engines?

>In a STOCK engine, you don't, unless you get ham fisted with the torque wrench.
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Pete said:
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You would be amazed at how much damage happens when someone thinks they need to torque the head studs to anything higher than 55ft/lbs "to contain high compression heads"
The one that always gets me, mill the head for higher compression and then assemble with two gaskets. Does even more damage.
 
johnneilson said:
You would be amazed at how much damage happens when someone thinks they need to torque the head studs to anything higher than 55ft/lbs "to contain high compression heads"
The one that always gets me, mill the head for higher compression and then assemble with two gaskets. Does even more damage.
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There are applications where more is better and too much is not enough.
I bought a B block with NO cracks once for 10 bucks. It had every head stud either broken off or stripped out of the block. Easy fix for me. No so much for others. I sleeved each hole with a tapered steel plug .750 on the OD.
The head had 2 o-ring grooves and the block had one that sat in the middle of the head ones. The stud spot face surfaces in the head were enlarged for bigger thicker washers. The head was installed with a solid copper gasket .030 thick.
The studs were made from SAE4340M and heat treated to 40RC. The washers were 1.4 inch dia and .250 thick 4340.
The off the shelf hard high nuts were torqued to 100 ft. lb.
This FLATHEAD engine never blew a head gasket and it went on to win the top fuel 4 cylinder class at the national championship drags running 97% nitroethane and 3% stuff.
It would have been nice to have had one of John's 5 main cranks and girdle back then.
 
Resurrecting this thread to ask: has anyone actually purchased ARP kit 151-4002? Is it real? I'm curious what their torque instructions were.
 
I agree that torque increases the stress in cylinder block threads, but so to does the stud stiffness. Try a rubber bolt analysis and vary the stud stiffness.
 
alexiskai said:
Resurrecting this thread to ask: has anyone actually purchased ARP kit 151-4002? Is it real? I'm curious what their torque instructions were.
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Been running ARP studs, washers and acorn nuts for 3 years. I have the B-F Super head and the torque is 60 pounds
 
Never mind, I asked ARP and they said:

“I’m sorry we haven't released that kit , it is still being tested with R&D.”

So there you go, no official guidance yet and no one has purchased the kit (officially).
 
I doubt that ARP will release a stud set for the Model "A", seriously there are bigger fish to fry. Also it should be noted that there are too many different heads available for the Mod"A", and will require many different set options.

Victor, Red's Headers offers ARP studs, you will probably need to measure and provide the lengths you wish.

As for suggested torque, 55 ft/lbs is all that is required. I have heard of people running more with higher compression heads but the physics do not change, over torquing will cause problems. I do believe that Larry Brumfield used 60 ft/lbs, that is not excessive.

The benefit is the ARP stud/nut combination will give consistent clamping for the applied torque and will not fatigue/yield like other questionable fasteners.

As to my experience with them, I use nothing else. From street applications up to race with 300 HP, in the stock locations.

John
 
When I bought ARP studs, I had to buy individual studs. No one I talked to there even knew what a Model A Ford was.
 
Full disclosure: An ARP employee did some work on several of my cars during vacations in Durango and created a Model A kit that was shipped to me.
 
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