anyone have an opinion they care to share about the subject. i'm about to order my bolts for my motor and was wondering what the difference is in the two, and if the 1/2" stuff is better for a high nitrous application. 500ish on motor, 300shot sparingly on top of that. thanks for opinions and insight.

Matt

 

The L19 studs will actually deteriorate over time -- the metal itself.

 

I have L19s and they hold my heads down nicely.

They are pretty expensive but if you do 1/2 you have to machine the block and buy custom studs for it. Probably comes out to the same price.

 

The L19's have a problem called hydrogen embrittlement and when they are subjected to moisture they will over time weaken and can break. Only real application that it's useful for is Rod Bolts and then it's still a pain in the ***.

1/2" studs can also weaken the deck surface too.... probably your best bet is to go with ARP head studs and a thick deck cylinder head and you will have very few problems with head gaskets then.

Bret

 

I have some H11 arp studs and handle 500hp on motor plus a 150 shot. I would say go for L19 and save the hassle of the custom machine work and studs.

 

Maybe you should look up hydrogen embrittlement then..... it's not really a good thing to have happen to a engine part.

Bret

 

Ok I'm just going to start writing this thread before some internet genius metallurgist tries to ******* correct me....

This info comes from Russell Sherman PE who IS a Metallurgist @ ARP.

L19: this is a premium steel that is processed to deliever superior strength and fatigue properties. L19 is a very high strength material compared to 8740 and ARP2000 and is capable of delivering clamp loads in the 230,000-260,000psi range. It is primarily used in short track and drag racing applications where inertia loads exceed the clamping capability of ARP2000. Like most high strength, quench and temper steels - L19 requires special care during manufacturing to aviod hydrogen embrittlement. This material is easily contaminated and subject to stress corrosion. It must be kept well-oiled and not exposed to moisture.

Cyclic fatigue failure originated by hydrogen embrittlement.

....L-19, H-11, 300M (mainly used in rod bolts (L19), tool steel pins (H-11) and connecting rods (300M) and Aeromet 100 and other similar alloys popular in drag racing, are partcularly susceptible (to hydrogen embrittlement) and extreme care must be exercizsed in manufacture.

Cyclic fatigue cracks propagated from a rust pit (stress corrosion)

....L-19, H-11 300M and Aeromet 100 are particularly susceptible to stress corrosion and must be kept well oiled and never exposed to moisture including sweat.


FREAKING SWEAT CAN CAUSE L19 to rust pit and stress corrode! Do you really want these things exposed to the moisture under the valve covers of your motor, let alone to the open environment right below the headers? Sounds like a good idea till you know the whole story.

Bret

 

I agree with Bret on this one. Even the guys at ARP said not to use L19 for head studs unless the motor will be torn down on a regular basis.

 

BTW, there are some materials that are at least equal to or stronger than L19 and will not corrode... but they are BIG $$$, at least $800+ for a set of custom studs in these materials.

 

If I remember correctly L19's are more expensive than $800.00.

 

ARP makes HS sets in batches. If they have a set on the shelf they aren't that much, but if you want a set made and they aren't planning a batch... they hit you hard!

Expect to pay close to $1k for an exotic set of HS which isn't easily contaminated and subject to stress corrosion.

 

I run some head studs, stock size, from a company called A1 or something. I forget the name, they were $400 or so. I'm a 346ci that made 754rwhp with 20 psi.

 

Holy old thread batman!!!

 

http://www.a1technologies.com/

I use A1 for special projects, Ferrari, etc.

I recommend Evans coolant be used with the L19 studs. Most of the aps I use L19 on are MID blocks which require Evans coolant anyway.

Steve

 

Ok now im wondering about the L19 bolts in rods. What kinda life expectancy should you expect out of em, should they be replaced every X amount of seasons? Or should you not worry so much if its in the connecting rods?

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

After reading that it seems its something ARP needs to worry about in the manufacturing process more then we need to worry about it as an end user in our applications? Let me know if im wrong, just seems its more of a worry during making the bolts then having em sitting in our motors with maybe a slight amount of moisture on them while sitting possibly. In the case of head studs only the surface area that might get wet might detteriorate, but i dont think that would be an area that would creat a failure unless it was left unnoticed long enough to eat down into the nut/stud enough to cause it to weaken.

Note, these are the mindless ramblings of soemone that is very far from a metalurgist, and by very i mean VERY! Just curious and trying to learn a lil more about this.

 

I am also curious how the L19 head studs have held up in the long term for people who have used them on the LS engines. Do they need to be replaced on a regular basis.? I may be using them in a MID block with Evans Coolant. On the A1 site they do not show L19 but they show H11 which has low corrosion resistance.

Steve I am also curious about your opinion on the strength on the MID with 1/2 in studs. I have read of some using 1/2" and even 9/16" on the standard deck with success. It appears to me that the strength of the boss for the stud comes from the block and not the deck but I can also see how the boss would be weakened by using a larger fastener.

Here is a link to ARP recommended materials for specific fasteners and their strength ratings. It shows L19 being recommended for rod bolts.


ARP Fasteners

 

Just use the ARP CA625 head stud kit, 260,000 psi... If you want to spend $1000 on head studs lol

 

Nice^

 

Why reply to a 10 year old thread?

 

To build up posts for the classifieds?