Who has blown a head gasket?
 

I had a well known mechanic tell me every truck he installed a Smart or H&S on has blown head gaskets....just curious who has done that, and if so, were you tuned at a high level and running hard?

I blew the head gausket on a 2010 on mild at around 30 pounds of boost. I know of 1 other truck that blew a headgausket towing on mild. My truck had 30K the other truck around 50K Both had a H&S

Lots of HG failures on tuners. The head bolts allow the head to lift when running boost and/or elevated drive pressure.

Get some head studs. Standard H11 or ARP 425's are more than fine to solve that problem. They will handle it unless you are gonna go for big power. Then the H11 HD's or the ARP Custom Age studs are your problem solvers. But they are creeping up on $1k just for the studs.

I have a 08 6.7L that I installed a Smarty S67 in Aug of 09 at 20,000 miles. My settings are CaTchater level 3 all parameters are set to default with torque management set at 2. I now have 52,000 miles and I have never failed the head gasket on my truck. I do monitor the boost pressure and back off the throttle at 30PSI. I normally do not reach 30 PSI unless I am towing my 5er uphill and this is when I may see 30 PSI on the boost gage.
Gages are required for any modification to these trucks and you need to know what is going on. You cannot act like a four year old with these and not expect the truck not to break.

Jim W.

I think the H&S developes more boost than the Smarty does, for some reason. I installed a Smarty first, but didn't like the idea of not being able to set defuel points. The first thing I picked up on when I put the H&S on, was how much more boost it pushed, and how fast it built up.

It would hit 35psi+ just pulling out of the drive.

I'm now running the 30 tune, without ATT, injector timing on 1 (stock), no power added in town, on mild when on the highway. Even with the defuel set for 30psi, I occasionally hear the H&S beep at me and I know it's time to back off.

This seems as close to stock performance as any of the tunes I've tried.

Studs will be in my future, just to be safe. I'd like to torque the head a bit more, but I just can't get to the rear bolts.

I'm going check with a shop this week to see if they will do it for me - anybody got an idea how much I should pay to have it done?

625's studs on my truck. No blown gasket here.

I've blown about 5-6 head gaskets on my 02, maybe more I've lost count. I've also run three - four different heads on that engine. That engine has block deck issues.

Most head gasket failures are caused by poor machine work from the factory. Most 5.9L and 6.7L engine I have deck the block anywere from 4 to 10 thou just to get it straight. Same goes for the head. I also have use a surface finish of 80RA on my surfaces.

That's just nuts, I don't even have words for it.[tapdshut]

There is no oversized, or different grades for 6.7L headgaskets available from cummins. Max piston protrusion spec is 0.020 thou

Factory 6.7L head gasket thickness is 63thou[laugh]

Cometic just released a new gasket. Might wanna take a look.

Thanks for the lead, but as of today cometic is about 2 months out from making head gaskets for the 6.7L

They only plan to make custom thickness head gasket MLS gaskets just like the factory.

Has anyone heard of the gaskets going with and XRT Pro set at STOCK. I will not be adding more power until I do the ARPs. Right now I just want all the crap off the engine, cleaner oil, and better fuel econ.
I will be monitoring everything with an EDGE Insight CTS.

The stock head bolts can be re-torqued up to 135 ft*lbs. The stock bolts have similar holding ablity to the ARP 425's. If you ever lose a head gasket down the road, the stock bolts make head gasket repairs so much faster than ARP's.

I can change a head gasket on my 02 in about 3-4 hrs depending on how many adult drinks that I consume.[laugh]

Once all the emission junk is off the 6.7L, it is very similar to the 5.9L

For quick head gasket repairs, you can leave in the injectors in the head and the turbo attached to the head. Just leave the head hanging, as the nozzles tips are exposed at the bottom of the head.

The last 6.7L head we fire ringed, we had to cut 5 thou off just so we could true it up, so the fire ring can be cut correctly. Most machine shops don't cut the head prior to installing the fire rings.

may be a dumb question, but what are the symptoms of a blown HG?

Well when my HG went I would see signs of coolant blowing out of the overflow onto the battery, even at idle you could see bubbles in the bottle....