nossty1

iTrader: (3)

I was told that ARP has a new set of 7/16s head studs that are stronger than there 1/2in headstud. They cost just shy of twice as much as the 1/2 stud but they dont require any machining. I think the 1/2in stud is close to 200,000 psi tensil streangth But the new one is 280,000 or something like that. Any one heard of thease?

stang90gt50

iTrader: (6)

Are these their L19's?

TransAm6383

iTrader: (1)

arent L19's rod bolts?

DERTY

L19 is a material type that you can get most anything from ARP made out of. They've had choices for a variety of different materials and tensile strengths. In the end, it's not the bolts that yield it's the thread in the block and the deck of the head that yield to pressure. Increasing the bolt diameter increases the engaged surface area making the block yield strength a little better in the threads than it is on the stock size bolts.

TransAm6383

iTrader: (1)

ooops

longrange4u

iTrader: (2)

Yea its the L19 material head studs... I just ordered mine. Erik Koeing reccomended them vs: 1/2" studs... said that they can be tq'd to 86lbs (I think thats what he said)

Nine Ball

iTrader: (38)

This guy is a smart one. That is exactly the reason for larger diameter studs. The regular ARP studs are stronger than the aluminum threads in the block already. Changing to a higher tensile material won't make the block threads stronger.

longrange4u

iTrader: (2)

Ok but what about an application in an Iron block?

smokinHawk

iTrader: (48)

exactly, how many times has a ARP regular head stud BROKE do to cylider head pressure in one of these ls1's?

also for the question about iron blocks: how many regular ARP studs have broke to to cylinder pressure in one of these ls1's?

longrange4u

iTrader: (2)

I guess the only thing I have heard is that the studs will elongate resulting in a lifted head... but I dont know of any instances that this has occurred with the ARP standard studs.

I purchased my L19's based upon Erik's recommendation to allow for additional TQ strength on the heads, thus reducing the chance of lifting a head.

I by no means have enough experience to contradict you or Tony..... I trust Erik as he taught at SAM for 20 years, but it may simply be a personal preference thing.

nossty1

iTrader: (3)

I was told the same thing but since I am using an iron block it would be easier and cheaper to get the l19 stud. Because the block is stronger. But then again I dont really know what I am talking about, that is why I asked.

DERTY

The head will yield underneath the spark plug long before the bolt or iron block will yield. Lifting a head is far better than holing a piston. The ARP2000 or L19 material would be fine in either event.

nossty1

iTrader: (3)

Could it handle 18psi on a 408 with an 8.5CR?

smokinHawk

iTrader: (48)

as long as the tune is there.

DJ's Z

iTrader: (10)

I have recently went with the L-19 ARP's from the standard ARP. Speaking in great detail with one of the engineers at ARP I was told 85ftlbs is the magic number for the LSx aluminum engines. May be different with the iron blocks. We have to be careful with the static torque to compenstate for the expansion of the aluminum heads/block. I don't really think the tensil strength of the fastners is the total issue here. AS most of us already know we just don't have enough head bolts per cylinder to keep the higher cylinder pressure guys from lifting the heads even with the L-19 studs. From what I understand any of us FI guys heading over 16-18 lbs of boost, we're probably going to have some issues...I know I have to keep and eye on my overflow tank and check the radiator level. Tensil strength of the L19's are 260,000psi compared to the standard ARP's at 190,000psi. Like Smokin Hawk said tune is critical...!!

Tiago

iTrader: (27)

I run the standard ARPstuds at ~85 ftlbs torqued. Never had a head lifting problem yet.

nossty1

iTrader: (3)

I guess I will let you guys know when I use them.

stevieturbo

regular ARP studs here at 80lbft. No problems.

KissMySSo1

iTrader: (2)

you tq the l19's to well over 100ftlbs

John02SS

iTrader: (47)

torque specs qouted look to be with a motor oil lubed stud. The specs on a moly lube is a lil less. When you guys spoke to ARP did they mention which one they qouted torque specs with?