Headstuds Options for compounds

TruckYou

TruckYou

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So I'm getting started with a new project right now, Dropping a P Pumped 12v in my Non ic 1st gen, with a built 47rh. IV spent all winter collecting parts, and currently one of the purchases I have yet to make is headstuds. It's going to have a s362/S475 compound set on it, big sticks, meth, 4kgsk. It is a hobby truck, and will be ran pretty hard. I due plan on pulling the head, resurfacing, and possibly O rings...

As for studs, I see there's alot if products on the market, and most have something good and bad to say about each. I planned on ARP 425s, but IV heard they aren't recommended for big boost compounds. 625s? A1? H11?

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Firerings and O rings are a foreign language to me. Nothing IV ever done before. If I'm understanding correctly, it's machining a groove into the head and inserting a steel ring? Do you know a ballpark idea of how much money a resurface/firerings or O rings should be expected to cost? I keep preaching to my self to spend the money (hopefully) once and be done with it.

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O-ring is when you cut a Groove into the head and insert a stainless wire into it to bite into the gasket better. A fire ring is when you cut matching grooves in the head and block remove the fire ring section from the head gasket and use a ring in place of it to help seal the combustion gases better.
 
Oh OK, so in order to firering you must have both the block and head machined ...

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TruckYou said:
Oh OK, so in order to firering you must have both the block and head machined ...

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That is the best way to do fire rings. You can do just a groove in the head with a fire ring but it will not hold up as well from my personal experience.

Fire rings also don't like heat cycles, they tend to prematurely crack when being used on a street truck.

IMO go with o-rings on a good flat head, with 625's, do proper retorques and you should not have anything to worry about.
 
For a street truck you need to go with o-rings in the head on a stock gasket. You can get away with stock bolts and carefully torque them to 140flbs or so. The shop local to me that does alot of these heads charges $300 for surface and
O-rings.
 
The cheap arp's and o rings have held 75psi towing and dd'ing for 5 years for me.

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A 1200 dollar set of studs and then another few hundred dollar oring or fire ring maching costs? All to hold a mild compound setup......guess I am doing it wrong with 425s and a flat head.
 
jlbayes said:
A 1200 dollar set of studs and then another few hundred dollar oring or fire ring maching costs? All to hold a mild compound setup......guess I am doing it wrong with 425s and a flat head.
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My old work truck had a s358 over s475 on a stock engine just retorqed the head when I put them on. I ran that for like 60k miles with no problems, bumped the timing from 18 to 23 and blew the head gasket on the first test drive.
 
High timing and compounds has always been a killer for me. I ran a 35/ht3b combo for years with stock head, head gasket, and head bolts at 16* and doing whatever i wanted with the truck and never had a failure. Then on the next truck with the same turbo set up but at 22* i couldn't get a gasket to hold with 425s and o-rings. I had the orginal head surfaced and even bought a new head and had it surfaced also. It would hold at 20* but would blow any higher than that. Ended up going to a big single and then it was fine.

So I'm not saying that $1200 studs are "needed" but just made a recommendation from my experience. I would rather have the piece of mind that it's over kill than wondering if it's on borrowed time.
 
Deck and o-ring the head ARP 425 are fine 3 re-torques . Find a shop in your area that has o-ringed a cummins head before or send it off to get done . Over 50 o-ringed 12v never had any trouble , Had as high as 110 psi with 14mm studs .
 
Put 625s in it with orings if you can afford to and be done. It will be the last time you touch the head unless you melt it down or want to port it later.

Personally, I like to spend some extra now and be done. Headgasket repairs are the most annoying repair on the truck next to the transmission and tappet cover. The A1 studs (very similar to 425) I put in my last truck felt like chit when I torqued them. Wished I went 625s the entire time.
 
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625s arent cheap but theyre good insurance. They dont stretch as much under load and are resistant to corrosion so you can re-use them for longer.
Theres a lot of labor involved in messing with the head. if you have any thoughts about porting you might want to do that at the same time.
timing, boost, drugs and beating on a cold engine are head gasket killers.
 
Standard ARP's and O-rings should do ok. Make sure to use plenty of lube on the nut, washer, and stud. You can over-torque them a little, but ARP doesn't recommend it.
 
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