maperformance

Would anyone be interested in an H11 head stud alternative? Pricing would be in the $530 range which is about $250 cheaper than ARP 625+, let me know!

DEFYANT

If its better, and cheaper, I could definitely see some interest.

cmac06

iTrader: (16)

Looked long and hard for some, but none were available when I bought studs. I'd be interested in a set. The custom 625 came out after I bought mine. That's a good price point also.

Brian Hoss

Are you claiming that the H11 studs are as strong as the ARP studs?

p8ntslinger676

if there is a 1/2" variant, ill buy a set.

JAX04

iTrader: (17)

Appears to me he is saying they have a higher tensile strength....

maperformance

Standard ARP head studs use 8740 chromoly which has a tensile strength of 190,000psi. Our H11 studs would have a tensile strength of 260,000psi which is equivalent to what i have been seeing in regards to ratings for the ARP Custom Age 625+ (although some claim 280,000psi) but at a much lower price point

This leads me to another question, do most people stay with the 11mm studs or do they modify their block to accept 1/2" studs?

DEFYANT

Some do modify for the 1/2" Heat Studs, but really at that point a 6-Bolt setup is usually needed.

maperformance

Very true, I guess an upgraded 11mm stud would be fairly popular then as people encounter head gasket issues with 4 bolt setups and standard ARP studs.

stevieturbo

If they were proven to be better than regular stuff, then I'd be interested.

Thing is...ARP are a well proven brand name to trust, even if the new studs arent widely used yet.

transam69230

iTrader: (49)

Make a set for the Dart Ls next gen block and I will buy a set. Got to remember guys who are buying studs like this are probably using a 6bolt heads too. I would make sure to do 6bolt kit is what I am getting after.

DEFYANT

MAP's H11 studs are used a lot in the Evo world, the same friend I mentioned in another thread uses their H11's at like 40lbs out of a 62mm Turbo... Hold fine.

1INSANEGTO

iTrader: (13)

Interested my 427lsx TT CTS-V needs these

Brian Hoss

So the A1 hardware is a better bolt and its tensile strength is better than the ARP plus its much cheaper? Is strength the only factor in a bolt that makes it superior to another, or are their other factors that come into play?

maperformance

It's mostly the material and manufacturing processes but depending on the application there may be design features like a dog point that can be of value also.

Please note that the pricing I outlined in the original post was for 4 bolt applications, I will have to look into pricing for 6 bolt applications and report back.

9sectruck

iTrader: (9)

I had a set of 625 on my bbc aluminum heads, torqued them down to 120lbs and after the first rebuild you could plainly see the indention of the washer in the head from the pressure the nut was putting on the head.
at what point does the extra strength of the stud not benefit as the head starts to collapse

maperformance

I can't say that I've ever encountered that, although 120ft/lbs does seem quite high. Here is an interesting blurb from a conversation I had with A1 technologies recently regarding different moly lube and torque values, it seems that extra torque doesn't necessarily equal additional capacity:

...you can achieve the same stretch of the fastener, stretch = clamp-load, with a lower torque. Lower torque means less torsion is applied to the fastener to achieve proper stretch. Tension, the stretch of the stud is one load, which applies the clamp force holding the head down properly. Torsion is the twisting that occurs due to friction when torque is applied to a fastener. This is a secondary load simultaneously applied while stretching the fastener, biaxial loading, is the technical term. Torsion serves no beneficial purpose to the proper loading, (stretch), of a fastener and is actually detrimental to the UTS (Ultimate Tensile Strength) of a fastener. Because torsion is a secondary load occurring while stretching a fastener is can reduce the UTS (maximum capability of a fastener) by up to 20% or more.

In a perfect world stretching a fastener then spinning the nut freely down to the head surface then releasing the fastener (stud) would achieve the proper stretch & clamp-load (preload) without any torsion load to the fastener. As this is not feasible the next best option is to achieve the desired stretch, clamp-load (preload) with the least amount of torsion load, which is caused by friction. This is why we prefer an assembly lube with a lower friction coefficient and utilizing less torque to achieve the stretch, clamp-load, desired.

stevieturbo

I guess that will vary with head designs and materials used. Something we dont have much control over.

Nut base diameter, washer diameter and thickness....I guess we do have control over that to a certain degree.

Brian Hoss

Isnt H11 the tool grade steel that got banned from aircraft because its brittle? Did the properties change that made it better recently? Cheap I get. What I don't get is why anyone would still manufacture with tool grade steel when there is much better material to be had. Or is the good stuff cost prohibitive?

p8ntslinger676

That and its very susceptible to oxidizing so it has to stay oiled and out of the water jacket or else it will lead to an eventual failure. plus you have to look at the market to see what they are willing to pay for something like this. one off pieces are not cheap and doing batch runs in the only cost effective way of making these sorts of items. If you look at the LS market you have two wildly opposed sides of the spectrum, one side (the minority) is willing just just throw money at it for the best parts regardless of cost, while the other side (the majority) would much rather buy a junkyard motor with some cheapy ebay studs and hope it lasts until it eventually takes a crap and they have to buy another one.