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Diesel of the Week

Turbocharged & Nitrous-Boosted 6.7L Cummins Engine

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We love seeing the power of social media in action. Earlier this year, we posted and shared info on a diesel engine build from LinCo Diesel Performance in a Diesel of the Week article. The shop also shared the posts about it on social media and YouTube. Within two days, a guy from the Chicago area called the shop saying he had seen the engine build on social media and wanted a price on a similar engine build for himself.

A couple days later, LinCo Diesel received a deposit from the customer and that turned into a much bigger engine build, as well as some custom transmission and truck work too. According to LinCo Diesel Performance owner Jeff McCord, the build turned into a $60,000 project. Not bad for a few social media posts!

The beginnings of 6.7L Cummins

McCord started LinCo Diesel Performance (LDP) in 2015 after deciding to get out of the heavy equipment business. He was in need of a new shop name that would let people know diesel work was being done there.

“Ever since we started the shop we’ve done diesel performance, but people didn’t realize it,” McCord says. “That’s why we started the performance business was for the name. We always did it, it just wasn’t as well known.”

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That secret didn’t stay quiet for long, and today the shop focuses primarily on Duramax and Cummins engine work for all kinds of applications, as well as transmission work and some parts manufacturing.

“What we’re most known for is Duramax work,” McCord says. “However, our experience and preference is to work on Duramax and Cummins. We work on common rail mostly, but we have roots in 12-valve stuff too. We also manufacture a lot of parts for 12-valve trucks.”

Manufacturing parts, doing complete transmission work and keeping all engine and machine work in-house is easy since LinCo Diesel Performance also has LDP Machine, a full engine machine shop, under the same umbrella.

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In fact, McCord just finished building a new facility for the Troy, MO-based LinCo Diesel Performance that is 15,600 sq.-ft. The machine shop is also in a brand new 8,600 sq.-ft. space right next door on the same property.

“We have about 25,000 sq.-ft. total on 6.5 acres, so we have plenty of room to expand more,” he says.”

Thanks to a growing social media presence, a new facility and top-notch diesel work for numerous applications, LinCo Diesel won the business of this latest customer looking to build a serious 6.7L Cummins for his 2014 crew cab short bed Dodge Ram.

“The engine is a 6.7L Cummins build, which featured a 6.7L block bored .020˝ over with a factory 6.7L crank,” McCord says. “We ended up doing some major upgrades to the block such as Wagler billet mains, which are extra-long 14mm main studs, and we used their steel girdle. We also did Haisley/ARP L19 14mm head studs.

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“The rotating assembly features Wagler Street Fighter rods and custom 16.5:1 Mahle Motorsport forged pistons with DLC-coated wrist pins. The block and head are fire ringed. It’s got a Hamilton 226 cfm street 6.7L head with big valves. We took that head and did some CNC exhaust porting and blended the valve throats and the guides as much as we could with the shelf on and picked up 25 cfm per runner on both sides doing that. We also unshrouded the valves, so it gained a lot of low-lift flow and top-end flow.”

While the crankshaft is just a stock 6.7L crank, LDP did things a little differently than most in the Cummins world. According to Jeff, most folks TIG weld the crank gear and cam gears on. However, on this build, LDP keyed the crank.

“I don’t know why nobody ever does that in the Cummins world,” he says. “We do it on the Duramax stuff every day, but you always see everybody TIG welding them on due to shearing the pin. The benefit to keying the crank is if you ever want to remove the crank, it’s much easier. Welding on a crankshaft is also never ideal for heat.

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“Keying the crank is just as strong, if not stronger, and you can always double key or triple key them if you’re running three or four CP3 pumps or a big 14mm inline pump and you’re worried about shearing it. We’ve even been talking about having gears EDM broached and double keying cranks. It’s a better way to do it than welding them.”

Some additional components put into this badass build were 110-lb. valve springs, XDP billet valve bridges, Hamilton 12mm pushrods, 1.5˝ tappets and rocker arms with DLC-coated trunnion shafts, a Hamilton 188/220 camshaft, a Fluidampr balancer with drill pin and full power retention kit, an electric water pump, Keating Machine billet bolt-in freeze plugs, and Fleece coolant bypass.

As far as the fuel setup on this 6.7L Cummins, LinCo Diesel used S&S 350% over injectors, an S&S 14mm race CP3 and an S&S SP3000 supply pump. They also opted for an S&S regulated return filter base.

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“That posed some challenges because they haven’t done lots of tests as far as in a chassis and with different era trucks, so we had to overnight fittings and we had to make some custom brackets for the ECM and reposition the ECM to allow the pump and fittings to clear,” McCord says.

A unique feature of the build is LDP’s first-ever redesigned dual breather billet valve cover. This is the first engine with those valves covers and they are in production now. It’s a dual breather with both breathers baffled. They have 3/4˝ -12 fittings on them.

“We’re in the process of working on a catch can with an integrated drain to drain back to the crankcase,” he says. “We’ll have a full kit available shortly.”

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To really give the build some serious horsepower potential, LDP chose a Stainless Diesel 485/96 5-blade “Godfather” turbo. And, on top of that, the customer requested a spool jet and two stages of nitrous on a progressive controller.

“We’re hoping for at least 1,400-1,500 horsepower on fuel, and 1,700 horsepower on nitrous,” McCord says.

While the customer’s transmission had already been built by another shop, LDP made sure it was up to snuff given the new horsepower levels this 6.7L Cummins would be churning out. And, it’s a good thing they took the time and effort to look at the trans.

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“The trans only had a couple thousand miles at 900 horse and it was already looking pretty ragged, so we wound up going back through it and refreshening it,” McCord says. “We pulled it apart and went back through it and upgraded it to a Sonnax 35-spline input shaft. We had a new converter built by Suncoast for 2,600 stall. We went with a billet direct drum, a billet forward drum, a billet band, a billet servo, and some other parts it should have had, but it didn’t. We also went through the valve body to give him a full manual valve body, which will make for a stout trans.

“We also did some fab work such as cleaning up under the hood and getting the wiring hidden and tucked away. We removed everything that we could, and I got a standalone harness from Firepunk Diesel, so the engine wiring is super clean. We also fabricated all the piping in-house and we retrofitted the radiator and intercooler to a third Gen (‘03-’09) aluminum intercooler, so it’s got a normal pressurized cooling system with the radiator cap and no surge tank.”

All said and done, LinCo’s custom work made this 2014 Dodge Ram one badass 6.7L Cummins truck – and that’s just what the customer had wanted.

“The customer wanted a badass street truck and something he can race on the weekends,” he says. “I think he plans to hit several ODSS events. It’ll be a street pounder and a weekend warrior. We even hauled the truck down to Maverick Diesel where Paul and the guys put a cage in it.”

If you ask us, this 6.7L Cummins build was $60,000 very well spent!

Diesel of the Week is sponsored by AMSOIL. If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected]

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