6.7 HG issues.

drive pressure in itself is not blowing head gaskets, but throwing on a wastegate to lower drive pressure, and a few other things is what is saving the head gaskets. On a stock turboed truck, I think i have only heard of one or two guys with wastegates blow a head gasket.
 
I don't think it's drive pressure either. IMO, it has more to do with Gasket or cylinder block design than anything else. The MLS holds up pretty good on the 5.9.
We are talking .1333ish liter increase, per cylinder. Fairly significant yes, but... big whoop.
Has anyone checked the difference in block pressure at 3000 rpm with and without the cooler in place? Anyone have pictures of their toasted gaskets? Are they burning between the cylinders? I have yet to see one come through our shop so I have nothing to go on.
 
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Snedge said:
We are talking .1333ish liter increase, per cylinder. Fairly significant yes, but... big whoop.
Anyone have pictures of their toasted gaskets? Are they burning between the cylinders? I have yet to see one come through our shop so I have nothing to go on.
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Yes, but ~10% increase in combustion deck surface area compounded by the additional peak cylinder pressure equals an extra 10-12 tons of force trying to punch the head through the hood...

Factor in decreased web width, thicker (less conformable) layers & shorter leak paths to the water jacket and HG failures are almost de rigueur.

Typically, combustion pressure lifts the head enough for hot gas to delaminate the layers & cause the thin fire ring spot-welds to fail in the narrowest part of the web.
5-6 is worst, followed by 4-5 & 3-4... if it's bad enough to separate 1-2 as well, chances are you don't need WOT to percolate the puke tank.
 
Drive pressure is not what blows the head gasket this discussion has been beat to a pulp in so many threads. It is a measurement that tells you of a problem in your engine a misbalance so to speak, and I can guarantee you that engines with high drive pressure blow more head gaskets than engines with drive pressure closer to one to one. It is just a balance thing I guess, compressor and turbine have to work together or the head gasket takes takes a chit in most instances.
 
was just reading reading all the 6.7 hg threads and it reminded me of all my 6.0 issues
 
700rmk said:
was just reading reading all the 6.7 hg threads and it reminded me of all my 6.0 issues
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HG issues are minor when compared to blown HPOPs, replacing injectors every 100k or less, exploded LP oil pumps, turbos with stuck veins, IPRs that you must have ninja skills to replace, blown oil coolers and cracked pistons. :kick: LOL
 
DP is definatley not the only contributing factor with the HG, the factor is not just the 40 or 80 lbs of boost Zach hamilton had posted a very good explanation of the effects of DP and a formula for the actuall cylinder pressure increase that it caused. The incylinder egr that is done with camshaft overlap allows the DP to be forced back into the cylinder that has the open exhaust valve. I dont rememebr off the top of my head the formula but it was along the lines of for every 10 lbs of DP over boost pressure = an additional 255lbs of cylinder pressure (10 x surface area of piston x stroke length and compression ratio) so its not just the simple 40 lbs blew my headgasket. I have ran a wastegate on my truck for about 10,000 miles and have run everything from Smarty 14ME (the one everyone said was blowing gaskets with the excess timing) to 23 TNT. I still have stock studs on my truck and to date still have no coolant problems nor HG issues. I know a couple guys that were running 625 ARP studs and still popping gaskets with Smarty and H&S they added a Wastegate and no more problem one actuall just grenaded the whole bottom half of the motor at over 900HP but had ZERO HG problems. I am a believer in them and have seen first hand the difference they make.
 
Thanks M Thomas, yes I run my own kit I played and ran multiple different spring sets and setups till I got the one I felt controlled DP the best while still maintaining EB functions.
 
The timeless question: who makes the best complete kit, that will address the above issue(s)?
 
Rob_Bones said:
The timeless question: who makes the best complete kit, that will address the above issue(s)?
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I have a prototype head gasket on the brown truck right now, that I will be installing when I get home from work, like stated above the weak link on these gaskets are the fire rings between the cylinders, this new gasket I will be trying has fire rings that are seperated from the head gasket much like an oring or fire ring job, but these dont have grooves cut in the head or block and will crush, there are about .010" thicker then the head gasket, which this one is .058" and I think stock gasket is .062", and the rings should crush down to the gasket thickness. It seems running these style gaskets, after the first motor warm up, a retorque is a must. I will be running this gasket with 425 studs and plan on torquing to 135-140 ft-lbs and doing probably 3-4 retorques, I was going to add a ewg, but decided not to and to try pushing this gasket and see how well it will work. I should have results in about a month.
 
I wish all this was easy to figure out but it isn't everyone has their own explanation for why they blow. Here is what I have done on mine I blew the first HG at 31,000 miles with a PPE tuner and all the EGR crap on. Dealer replaced the HG. Then deleted everything and have been running an H&S mini max blew HG again at 65,000. So this time Dealer agreed to do what I wanted as long as I paid for the parts and they covered labor under warranty. This time I got a fire ring HG from Haisley and ARP head studs so lets see if it will stay together until she hits 100,000. My personal thoughts on the HG blowing is me running the chit out of it and always making the truck hold gears longer thus turning higher RPM's and the last time it blew I was using the exhaust break.
 
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I have only had my truck for about 3K miles, the truck stock is boring as hell. I am going to try the external waste gate from black ops diesel along with all the deletes and a smarty jr. Hopefully the hg will continue to do its job.
 
Someone mind sending me a pm with Greg's price on 625's??
 
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