ScottGregory

Box came in the mail today with the new studs. When reading the instructions I want to be clear on the proper way to do it.

This is what is says:
Lube studs, washers and nuts with ARP lube only.

Following manf torque sequence, cycle the head studs three times (tighten, then loosen) to the torque spec of 150 ft lbs before tightening the studs a fourth tand final time to 150 ft lbs.

This is my interpretation:
Following the manufacturers torques sequence, torque the head up to 150 ft lbs. (will probably do it in increments) Then cycle through the bolts (loosening and then tightening) back to 150 ft lbs three times.

Or does it mean:
Following manufacturers torque sequence, torque the head to 150 ft lbs of torque. Then loosen the head back up (all bolts )and retorque per the sequence back to 150 ft lbs three times.

Never installed studs before and this head is fire ringed, I'd hate to damage the seal by doing it wrong.

Of coarse I plan on several retorques.

Thanks for your advise.

ScottGregory

Called ARP.
Torque head up to 150 ft lbs in three increments using manufacturers sequence. Then go around head loosening and then retightening three times. Recommended but not critical on the third time to remove nut and washer and relube before torqueing to final 150 ft lbs of torque.

Not critical but recommended is to retorque after the first heat cycle.
Told me that on some vehicals (like a ford) that it is a real pita to get at the head bolts, but if you can get at them then do it.

He didn't get my humor when I suggested that you can get away with it on a ford because they can't develop the power a Cummins can. None the less, even with my poor humor and all, he was a pleasure to deal with.

I will probably check torque quite often initially.

HOHN

Great to know.

I hope the fire rings work out well for you-- I've heard they have a tendency to crack the head sometimes. But that was mostly years ago, and I think the technique has been refined a bunch since then.

jh

ScottGregory

First I heard about cracking the head. Have heard about the rings cracking where they are joined if they are not annealed well enough. I suppose that could cause the head to crack if they have hard spots. I talked to alot of vendors and did alot of reading on both O-rings and Fire Rings. Everybody had their little bit of fufu dust they sprinkled on their methods and dirt on everyone elses methods. All methods including stock gasket and bolts have been succesful to some degree, most importantly, no method is perfect and all methods have failed.

In comparing O-rings vs. Fire rings, I picked fire rings with extra clamp pressure that these studs offer. In my opinion, a properly done fire ring, (including the prep of the head and block) has the best chance of success in these engines. No matter what type of seal being used, if there isn't sufficient clamping pressure from not enough torque, or a lower modulus fastener (whether material or size) is used, you run the risk of failure.

Anyways, if these fail, I have another head to use.

HOHN

Good to know.

I'm super curious just how much the stock HG can hold with some serious clamping from 625s.

Justin

ScottGregory

I don't know, that same thought went through my mind as well.

Before I go further I should justify that these are my opinions, it is not like there is a whole slew of diesel heads in my neck of the woods that have been their and done that. Let alone share thier oops experience with me.
I based this on my past experience in other applications.


What stopped me from continuing down the route of using the stock gasket was what I believed to be a limiting factor in how much crush I could get in the stock fire ring before I got into crushing the rest of the gasket.

I drew that analogy from back in my college days when I worked with high vacuum systems. We used copper ring gaskets to seal the ports on the system. The flanges had "rings" in them that would crush the copper. If we tightened them too tight or had too soft of copper the flange would leak as the sealing pressure was being distributed across the whole flange surface and not the ring anymore.
I think the standard studs can get you to this point with a stock gasket. This is were the o-rings come into play as they effectivley focus the pressure at the gasket fire ring allowing for higher clamp pressures. However this were I got off the o-ring band wagon. In my opinion, at high clamping pressures the gasket fire ring will deform plastically from the oring in an unknown fashion. By unknown I mean when it deforms especially towards the piston, it will have to shrink either by buckling or getting thicker. This could easily compromise the seal and potentially relax the clamp pressure on the head if it flow too much.

That is why I ended up with fire rings using a stiffer stud. Both the 625 and going to 14mm studs are not cheap. The 625's ultimately have less "issues" in they don't introduce a potential for machining error or result in problems of localized deformation due to thinning of the block. The studs have enough clamping pressure and high enough modulus to insure that the ring plastically deforms and seals while minimizing the amount of elastic movement taking place under load. Fire rings in my point of view are the best suited for this high of clamping pressure. They are designed to flow when clamped, and will do so in a predictable manner. (assuming they are made correctly)

my 0.02. I am open to different hypothesis as I have been wrong enough times in my life to not be offended when somebody has better or more correct thinking.

Bjans

who are you having do the work? Whos rings are you using?

stuckey200224

anyone tried the new studs from haisley they are supposed to be the same as the 625's but only half the $$$.

LanceD

I will sacrifice my truck for this study, just send me some 625s and I will put the stock HG to the test. I think its even the original HG too.

DiezelPowa12v

The H-11 studs are recomended to be brought to 140lb ft torque, while 625's are supposed to be brought to 150 lb ft. Either IMO will work for even high HP/NOS setups.

One tip for a firering install is to use gorilla glue and get those rings glued into the head very well which aids in setting the head on the block and lessens the chance that the ring could "miss" the groove in the head.

trefling

torquing down the 625 was some serious work. O-ringed head and 625's make for one serious seal. I blew my HG on the standard ARP's, but these 625 are really amazingly strong

paulb

Which head gasket did you use?

XLR8R

... hopefully marine.

trefling

yes the marine gasket

renopker

I differ abit I'm not a big fan of studs for max yea do them, however I like Orin's and new bolts in Cummins that are street driven. I feel that all the extra clamp pressure with big studs distorts the block and head why Else would it need to be bored and honed with plates.Bolts hold the head down and Orin's holds the fire-ring in the gasket from blowing out.The biggest problem I have found with orings is either there not located right or the wire protrusion is wrong which will cut in and distort the gasket fire ring along with the head causing other problems like water leakage or just plain failure.