Resolving the 6. 7L Cummins’ Mind Gasket Issues—For Good
The particular 6. 7L Cummins is hard in order to beat in the diesel world. The particular common-rail inline-six features the greatest stroke, the biggest bore, and the majority of displacement in the segment. Its capability to spool an S400 has basically killed off the need to run substance turbo arrangements, and the stock shot system can support 550rwhp or more. However, head gasket failure is a huge problem in the 6. 7L world—especially on trucks that spend their particular lives tuned and hooked to some trailer. We’ve seen some proceed 200, 000 miles before raising the head while others can do it by 50 % that time. With a second-gen turbo exchange, an S467, and aggressive fine-tuning onboard, the 6. 7L fourth-gen in this article pulled off the feat in only 114, 000 miles.
Luckily, the owner programs to keep his Ram for the long-haul, and as such decided to do things right the very first time. Instead of sending the head off for any simple pressure test and resurfacing, it had been shipped to Scheid Diesel for a couple additional reinforcement measures. And because of Scheid’s quick turnaround, a decked head cut for fire-rings plus fitted with screw-in freeze connects was returned to his front door in just four business days. Between your addition of fire-rings, ARP mind studs, and screw-in freeze connects, the head is about as bulletproofed since it gets for a 550rwhp truck. To get a look at what the two-day job required, along with a glimpse into the hot re-torque process that’s required when working fire-rings, keep reading.
Though the climactic drama associated with puking coolant from the degas container never occurred, the owner did spot the upper radiator hose was pressurised and stiff each morning before proceeding into work (a telltale indication of head gasket failure). Whenever he could finally afford to have the pickup truck down for a week, the head had been pulled on a Saturday, shipped in order to Scheid Diesel on Monday plus back in his hands by Fri.
As the head was in the care of Scheid Diesel—the shop that would resurface this but also machine it to accept fire-rings and screw-in style freeze plugs—we inspected the original head gasket. This ended up letting go between canister numbers 2 and 3. In the early stages of failure, no increasing in coolant level or puking from the degas bottle had happened yet, but the engine would get hot as if an air pocket had been present in the cooling system.
Readying the obstruct to accept the resurfaced head, we-took a right angle die grinder plus a mild Scotch-Brite pad to the porch. With all of the original head gasket materials removed, we double-checked the prevent for trueness using a straight advantage and a feeler gauge. It examined just fine (as most Cummins prevents usually do). Then all mind bolt bores were hit along with compressed air to ensure no liquid or debris was present (fluid or other contaminants can screw up your torque readings).
You might find this technique helpful if you ever find yourself performing exactly the same job. To save time when tugging the head and reinstalling it later on, both the turbo and exhaust a lot more were pulled away (and kept away) from the head using a ratchet strap. An existing hole in the fender was employed as the passenger aspect hook point.
For utmost sealing within applications that see excessive canister pressure, fire-rings have long been a well known upgrade. Cut at Scheid Diesel’s new machine shop facility within Terre Haute, Indiana, the fire-ring grooves measure 0. 040-inches strong and measure 4. 340-inches within diameter.
The fire-rings supplied by Scheid are manufactured from mild steel and measure zero. 105-inches thick. When the head will be torqued down, they crush, developing a tremendous seal around the combustion part of each cylinder. While some believe fire-rings should be reserved for competition-only programs, they’ve proven highly reliable within street-driven, high-mile applications—so long since they’re installed properly.
In high-horsepower programs and sometimes due to age, the standard, press-in freeze plugs can drop out of the factory head. When they perform, coolant disappears and quickly combines with engine oil. By engineering all eleven internal freeze connect bores to accept threaded, screw-in design freeze plugs, Scheid rules out there this notorious failure from actually occurring in the future.
Regardless of when a 6. 7L Cummins goes down due to a blown mind gasket, in almost every case ARP head studs go back in whenever things go back together. Such was the case here, with ARP2000 material fasteners getting the call (PN 247-4202). Even though plans to push the truck into 700-rwhp territory lay ahead, ARP’s standard studs, in conjunction with the fire-ringed head, should have not a problem coping with the added cylinder stress that will come with that type of energy goal.
After the block’s deck had been cleansed up and wiped spotless, a good OEM four-layer MLS head seal from Cummins was set in location. However , in order to accommodate the metal fire-rings, the factory head seal was void of its own fire-rings.
Prior to the head could be lowered onto the particular block, each fire-ring was occur place within the head gasket. Different shops recommend gluing the fire-rings in place with some sort of adhesive so that they don’t move when the head will be installed. We didn’t opt to stuff the fire rings in place, yet we did take special treatment when dropping the head down.
Before the mind could be lowered onto the prevent, each fire-ring was set in location within the head gasket. Various stores recommend gluing the fire-rings in position with some sort of adhesive so they do not move when the head is set up. We didn’t opt to glue the particular fire rings in place, but we all did take special care whenever dropping the head down.
For optimum precision when torqueing down the head, every stud’s threads were hit having a coating of ARP’s Ultra-Torque. Each sides of the included washers, combined with the bottoms of each 12-point nut, had been also bathed in ARP’s securer assembly lubricant.
Next, it was time to reattach the Steed Speed exhaust a lot more to the head. New multilayer wear out manifold gaskets were sourced straight from Cummins for a leak-free seal. Because of leaving the manifold attached to the particular engine’s S400 throughout the duration from the job, no T4 gasket has been required.
With the placement of the head on the block examined and then re-checked to confirm all had been well, we began dropping all of those other ARP head studs into location. It’s important to note that the 6 studs measuring 6. 625-inches long install on the exhaust manifold part (all other 20 studs are usually slightly shorter in length). As soon as each stud’s threads had been began into the block, we ran all of them in using an electric impact and also a 5mm Hex socket, but had been careful not to take them past the stage of being snug.
Following ARP’s torque series (and working from the inside-out), the top studs were torqued in 3 rounds. However , and due to the utilization of fire-rings, we deviated slightly over the torque specs listed for its ARP2000 studs. On the first round, all of us went with 50 ft-lb, when using 100 ft-lb for the second. In the third and final round, we-took things to 150 ft-lb.
Any time you break the particular seal on the 6. 7L Cummins’ injection system, it behooves you to definitely start with fresh O-rings and even give food to tubes when necessary. This designed the external O-ring on the entire body of each injector had to be picked away from, replaced, and eventually lubricated using clean engine oil prior to installation.
It goes without saying the injector combustion seals (i. electronic. nozzle washers) should always be replaced whenever the injectors are pulled. In order to finagle the seals all the way in the injector nozzle, we used the plug trick (a 9mm).
We reused the particular factory injector feed tubes, yet made sure to reseal them with the proper O-rings. Then they were installed plus torqued to spec. When the injections are upsized in the future, the owner programs to start with brand-new Bosch units.
Upon ensuring the injectors were spotlessly expending after having lubed each unit’s body O-ring, they were reinstalled. The next phase was tightening the injector keep down bolts to spec: 93 in-lb.
To maintain the valvetrain in perfect synchronize, each pushrod, valve bridge, plus rocker was returned to the exact same spot it was pulled from a couple of days prior. Once the rockers were torqued it was time for a quick control device adjustment.
Because valve lash adjustment needs to be performed twice with fire-rings within the mix (before and after the hot re-torque process), they were left loose (ish) on the first go round. Afterwards, during the final running of the regulators and after re-torqueing the head studs, the particular intake valve lash was arranged at 0. 010-inch (the center ground between the 0. 006-inch plus 0. 015-inch allowable variance) as the exhaust valve lash was modified to 0. 026-inches.
Continuing on with all the reassembly, the intake grid dish, fuel rail, and high-pressure gas lines were reinstalled next. Next, the existing Glacier Diesel Power consumption elbow was bolted back in location above the grid heater.
In order to very clear the rearmost driver side mind stud, the 6. 7L Cummins rocker box has to be notched away. Once we’d tackled that, we all installed a fresh O-ring in the rocker box groove and bolted this to the head.
With everything buttoned upward (and per Scheid Diesel’s instructions), the engine was fired up plus allowed to idle until thermostat opened up. As you can imagine, this takes some time, however, you don’t want the head gasket to become exposed to any amount of boost till the hot re-torque sequence has been finished. After the engine has seen the first heat cycle and already been re-torqued, you can throw the book in it.
Tearing back into the engine as soon as possible upon shutting things down, the particular torque wrench (still set to a hundred and fifty ft-lb) went back on each mind stud nut. During the hot re-torque process, we were able to get any where from a quarter of a turn to a half-turn out of many of the fasteners. Then, so that as previously mentioned, the valves were operate once more, and the job was lastly complete.