Just an oberservation, at the price they want, their normal price should always be 10% off Cookie might want to check with Clay over at Riffraff Diesel Performance. IMO

 

id go check with clay at riff raff diesel - 5418791052 he could do ya a better deal. even with their 10% off.

 

I've seen the ARP 7.3 Head Stud kits for less than $600 everyday price.

 

By all means check with Clay and anybody else.. He pays the same price if not more than I do.. There was a price increase on these by the way.

We are working on becoming a dealer for A-1 technologies so we can sell H-11 headstuds. They are far better IMO.

 

Sourced a set of ARP studs off e-bay this morning for $545 shipped. Got a shipping notice less than 30 minutes after I posted the payment.

 

Good, you'll like the reassurance from the head studs. Now it seems like it's time to put the 1.15 housing on that 38r, now you got the oil and head studs, you can turn that tuning up a little bit more!

 

Thats a good price!

One reason we are going away from ARP's is we have noticed alot of failures with them lately. My buddy Bryan has blown 2 (yes TWO) headgaskets with ARP's, and I know of several others that found the studs stretched on the ARP's and not reuseable.

 

As I predicted the driver's side rear is the weakest link but as I'll discuss there're two different ways a head gasket can fail there!

I also commented that a stock gasket is probably your best choice.

To be confident you've actually solved your problem you need to figure out if it was caused by the increased CP from your recent mods exceeding the MSP in the vicinity of the driver's side rear or by the increased CP stretching the head bolts and lifting the head in the vicinity of the driver's side rear. Of course any lifting of the head reduces the MSP but just because you've located the problem to the driver's side rear doesn't necessarily prove it was caused by head lifting because the concentrated CP in that vicinity might've simply exceeded the MSP there without any lifting of the head at all.

Since MSP={clamping FORCE}/{material AREA} psi if the CP exceeded the MSP without any head lifting then the only fixes are some combination of 1) increasing the clamping FORCE, 2) trimming some material AREA from a stock head gasket in the vicinity of the driver's side rear to concentrate more of the clamping pressure there, or 3) reducing the maximum combustion pressure by retarding the injection timing some.

In principle a head stud can provide more clamping FORCE than a head bolt does but only if you increase the torque on the stud nut to a higher value than was used on the bolt. The threads in the block are the weakest link and the ARP directions say to use the OEM spec when torquing their stud nuts and this gives the same clamping FORCE as you'd get using bolts.

The way I interpret the above statement is that if you use the same OEM specified torque on both studs and bolts they both provide the same MSP which is consistent with the equation for MSP and that this test was done with a low enough CP so that neither the studs or the bolts stretched enough in response to the CP to allow the heads to lift and thereby reduce the MSP.

The pre-load FORCE on the studs from their static torque provides the clamping FORCE in the MSP equation and then there's an additional pulling FORCE on the studs due to the CP trying to lift the head. The threads in the block are the "ultimate" weakest link and they need to handle both the pre-load FORCE plus the additional pulling FORCE so it's a zero sum game. Higher torque to get more MSP reduces the available additional pulling FORCE to accommodate higher CP.

If your problem was the bolts stretching enough in response to the CP to allow the heads to lift then studs might be the fix because for a given CP load they stretch less than bolts. However it's possible that studs are so strong that a high enough CP will pull them from the block!

I suspect a "shotgun approach" has the best chance of fixing your problem... 1) use studs to reduce stretch in response to CP, 2) increase the MSP by using thread locker on the studs and applying a little more torque than the OEM spec to increase the clamping FORCE and if possible trim some material AREA from a stock gasket to concentrate more of the clamping pressure.

However based on the quote below I'd still be very suspicious that your injection timing might be too advanced and producing too much CP so I'll add 4) reduce your maximum combustion pressure by retarding the injection timing some. An injection timing which is too far advanced by only a small amount drastically increases CP and reduces HP.

 

Too much boost from the twin turbo Cummins?

 

He is wastegated to 60 psi.. I would think they would hold at 60 psi , his truck is capable of 80+ psi

 

Neither studs or bolts should ever be reused in high HP applications. Yes you can sometimes get away with reusing critical bolts, gaskets, etc.., but you don't have much confidence you're getting the same holding power as with new ones.

In response to torquing the head both studs or bolts need to stretch by an amount that's considerably larger than the above amount for differential thermal expansion so that temperature changes can be accommodated while still providing the necessary clamping FORCE.

On the other hand to keep the heads from lifting in response to CP you'd like to have no additional stretching of the studs or bolts after they're torqued but since they do continue to stretch in response to higher CP you reach a practical limit as to the maximum CP that can be achieved using an approach based on clamping FORCE. Then you have to "O ring" the cylinders to operate at a higher CP!

 

Bummer I agree, you would think that the studs could hold that pressure.

 

I was searching for information on the pros and cons of using a head gasket dressing and I came across this "Physics 101" which is a good read before torquing a head... Gasket Works Physics

"A key factor that is not considered often is that the fasteners not only hold down the head but also PULL-UP on the block. The threads within the block maybe weak. Some spots within the block are weaker than others -depending upon how much metal is around them. When these weaker spots are stressed they "give" more than other areas. This can actually deform the block and dimple the deck surface a bit. This under-appreciated problem can create sealing dillemas. One method used to mitigate against this effect is to study each motor and relieve (chamfer) the holes where the fastener enters the block."

"The more torque that is applied onto the block the more chance of distortion. This distortion is usually seen at the weakest places at the narrowes point of the bore and at the top of the cylinder. At the top of the cylinder where the compression pressures are always greatest any excess distortion will nullify any benefit of that extra clamping force. Blow-by of gasses will cause premature gasket burn through and less horsepower. "Less maybe best"."

Here's the link to their special spray on head gasket dressing... http://www.headgasket.com/contents/_...label%20v1.pdf ...I used a similar product 40 years ago on my racing engines and I followed the exact same installation procedure that's described below.

"I spray the gasket with about 4-5 thin "DUSTING" coats on both sides building the thickness of the dressing. (This dressing will compress substantially and fill in the nooks and small imperfections.) I let the gasket air dry for about 15-20 minutes, preferrably longer (over night). Applying any gasket dressing too soon and torquing immediately will just force the dressing out prematurely. The coated gasket should feel dry but not cured. I place the gasket on the block and place the head and torque to 10 lbs and let sit for a while (overnight if I can). At the track If I'm rushed I torque up at 20% increments until done. Otherwise I'll wait until morning to finalize the torque procedure."

 

Nice!... Thanks.

 

IT's Wrench Time!! We'll let y'all how it went later this evening .