When you have this... Brand loyalty lines get blurred every time guys start talking about diesel engines. Dodge doesn't make the Cummins, Ford doesn't build the Power Stroke, and GM had to team up with Isuzu to design the Duramax. The reality is that each one of those engines could wind up in a bunch of different vehicles. Who's to say what badge should be on the hood? But want this! The only limits to slipping any of these engines under the hood of a different truck are your own skills. Seeing as how the Cummins B-Series engine is probably the most popular engine for swapping, we wanted to follow along and see just what it takes to pull something like this off. We knew Bryan McCully of Fabworx Off-Road had been planning a factory-appearing Cummins swap for his '96 GMC K3500. So, we thought we'd follow along. Bryan McCully began his swap by removing everything from the front of his '96 GMC K3500 to make pulling the engines in and out easier. McCully's truck was originally powered by a 6.5L turbodiesel. The 6.5L made 114 hp and 243 lb-ft at the rear wheels on a Mustang chassis dyno. After pulling the engine, he sold it for $500 and never looked back. Bryan McCully began his swap by removing everything from the front of his '96 GMC K3500 to Sitting side-by-side with the 6.5L, it's clear the second-generation Cummins inline six-cylinder (left) is bigger in every dimension. When shopping for a donor engine, McCully knew he'd be ahead on time and money if he had a complete donor 5.9L Cummins Dodge truck to pull the engine from. He found a '95 two-wheel-drive Ram that had been T-boned on the driver side. Plan on spending around $4,000 for a wrecked donor Dodge. When shopping for a donor, avoid anything that has been on fire or hit in the front end. Sitting side-by-side with the 6.5L, it's clear the second-generation Cummins inline six-cy Using a manual transmission will make any Cummins engine swap easier. McCully's donor two-wheel-drive Dodge and recipient GMC 4x4 both had New Venture Gear NV4500 five-speed manual transmissions. Using a manual transmission will make any Cummins engine swap easier. McCully's donor two- As you can see the input shafts and clutch mechanism are completely different. Fortunately, these pieces proved to be interchangeable. As you can see the input shafts and clutch mechanism are completely different. Fortunately Jack Arrington was in charge of the transmission parts swap. Here, he removed the front input bearing retainer and input shaft from the Dodge NV4500. Jack Arrington was in charge of the transmission parts swap. Here, he removed the front in He cleaned it, checked the gear and bearing for wear, and installed the Dodge shaft back in the GMC NV4500. All NV4500 transmissions require Castrol Syntorq LT (low temperature) 75W85. Don't try to cheap out and use anything else. He cleaned it, checked the gear and bearing for wear, and installed the Dodge shaft back i • Page 1• Page 2• Page 3 Arrington cleaned up the new hybrid Dodge/GMC NV4500 and bolted it back up to the GMC's original Borg-Warner transfer case. With the Dodge input shaft and bearing retainer in place, the original Dodge/Cummins flywheel, clutch, clutch fork, and throw-out bearing could all be reused. Even the Dodge hydraulic slave cylinder bolted back up and worked with the GMC's clutch master cylinder and hydraulic line. The Dodge bellhousing added close to 3 inches to the overall length of the drivetrain, though. Arrington cleaned up the new hybrid Dodge/GMC NV4500 and bolted it back up to the GMC's or With the 6.5L engine out of the way, the original engine mounts were torched off the frame and ground smooth on both sides. This was the perfect time to hose the whole engine compartment down with some Simple Green and rinse off the gunk with a hose. With the 6.5L engine out of the way, the original engine mounts were torched off the frame The donor engine was a second-generation Cummins with the simple yet powerful P7100 injection pump. Rated at 175 hp at 2,500 rpm and 420 lb-ft at 1,600 rpm, this engine's a few modifications away from producing twice as much power as any 6.5L ever could. The donor engine was a second-generation Cummins with the simple yet powerful P7100 inject When lowered into place and bolted up to the transmission, it became clear the Cummins engine would have to be offset slightly to the passenger side of the truck. This position put the Dodge A/C pump into the passenger side of the GMC's frame and the exhaust downpipe into the firewall. It also became clear just how tall the Cummins engine was compared to the 6.5L. McCully was able to sit the engine lower in the frame than most people could because his truck has been converted to a solid-axle front suspension. He didn't want to put one on his truck, but McCully concedes that a 3-inch body lift would make this engine fit a lot better in an '88-'98 GM truck. When lowered into place and bolted up to the transmission, it became clear the Cummins eng With the Cummins engine hanging from the engine hoist, McCully went to work positioning the powerplant. The engine has to sit low enough for the hood to clear, high enough not to interfere with the steering, and tilt back far enough to maintain a reasonable rear driveshaft angle. When he was sure he had his Cummins in the right spot, he built these 3/8-inch steel plate frame mounts to tie into the factory Dodge truck engine mounts. With the Cummins engine hanging from the engine hoist, McCully went to work positioning th With the Cummins back in the truck, you can see how the fabricated mount captures the Dodge/Cummins rubber mount securely. From this angle, you can also get an idea of how little clearance there would be between the stock IFS differential and the Cummins engine block. Installing a 4-inch lift kit that lowers the factory IFS differential would free up some critical real estate. With the Cummins back in the truck, you can see how the fabricated mount captures the Dodg Here's where the new exhaust downpipe interfered with the GMC's passenger-side firewall. McCully removed the factory sound insulation from the firewall and sheathed it with a piece of 1/4-inch high-temperature heat insulation. It's not clear in this photo, but the GMC's factory heater core fitting and heater hose also ended up very close to the exhaust. McCully wrapped them with insulation as well to prevent damage. Here's where the new exhaust downpipe interfered with the GMC's passenger-side firewall. M Cooling a diesel is critical. Ironically, the indirect injection 6.5L GM diesel will inherently need more cooling than the direct injection Cummins engine. McCully thought about using the original GMC radiator, but in order to package the Dodge's intercooler in front of the radiator, he decided to stick with the Dodge unit. Cooling a diesel is critical. Ironically, the indirect injection 6.5L GM diesel will inher With the '96 GMC radiator support out of the truck, McCully began trimming and clearancing it for the taller Dodge radiator. He decided to reuse the GMC's radiator mounting system (rubber isolators on the top and bottom), but in hindsight thinks he would have been better off modifying the GMC support to use the Dodge's side mount rubber grommets instead. With the '96 GMC radiator support out of the truck, McCully began trimming and clearancing Originally, the plan was to saw out the radiator support in the areas traced out by the white paint lines. This would need to be done to make way for the Dodge intercooler tubes. By the time he was through, McCully removed almost twice as much metal as he planned in order to fit the tubes around the GMC's frame. Custom mounts were then made to hang the intercooler in front of the radiator and still leave room for the factory GMC A/C condenser. Originally, the plan was to saw out the radiator support in the areas traced out by the wh With the radiator, intercooler, and A/C condenser test-fitted, McCully had to find a way to mount the Dodge A/C compressor and alternator. Originally, he thought this water outlet/mount off a Kenworth truck application from Reliable Goods would do the trick--but no such luck. He used it anyway and built his own adapters to hang the accessories high on the passenger side of the engine. With the radiator, intercooler, and A/C condenser test-fitted, McCully had to find a way t McCully wanted to use a mechanical fan, but his second-generation Cummins pulley was too tall and would have pushed the fan blades into the radiator core. McCully swapped it for an '89-'93 (first generation) pulley (right) and gained almost 2 inches of clearance. This swap required McCully to remount the factory Cummins serpentine belt tensioner in order to reuse the stock length fan belt. Dual electric fans would have been easier but more expensive. McCully wanted to use a mechanical fan, but his second-generation Cummins pulley was too t • Page 1• Page 2• Page 3 Since the previous owner had upgraded the donor Dodge with a 4-inch exhaust, it made sense to adapt it to the GMC. The two systems were nearly identical in length and only required McCully to rework the downpipe and hangers in order to make it work. Since the previous owner had upgraded the donor Dodge with a 4-inch exhaust, it made sense Remember those 3 inches of extra bellhousing length? Coupled with the fact that the Cummins needed to sit lower in the engine compartment (just to clear the hood!) meant a custom transmission crossmember would have to be built. A few sections of 2x3-inch 1/4-wall steel tubing were used to support the drivetrain yet still clear the front driveshaft and leave room for the 4-inch exhaust. Remember those 3 inches of extra bellhousing length? Coupled with the fact that the Cummin The new transmission location meant the hole in the floor would have to be opened up to accommodate the new shifter position. After rowing through the gears a few times, McCully found the shift lever would hit the center console. He pulled the shifter mechanism out of the NV4500 and heated it up with a torch in order to bend it for clearance. A new carpet kit for an automatic transmission truck (no hole) will have to be ordered to make the new install look factory. The new transmission location meant the hole in the floor would have to be opened up to ac With everything physically bolted in place, McCully enlisted the help of Jesse Slye and Adam McLauflin to plumb and wire his new mill. The GMC's fuel feed and return lines were hooked up to the Cummins lift pump on the driver side of the engine. The GMC's electric lift pump was then replaced with a short piece of 3/8-inch metal line. McCully was able to reuse the Dodge's mechanical throttle cable by retrofitting an accelerator pedal from a '96 gasoline GMC truck (the 6.5L engine is drive-by-wire) and reworking the end of the pedal linkage to achieve wide-open throttle. At this point, the power steering pump was upgraded with a unit from PSC to supply the GMC's hydroboost brakes yet still mesh with the drive gear on the back of the Cummins vacuum pump. Wiring proved to be the slowest part of the swap. McCully purchased factory-wiring diagrams from his local Dodge and GMC dealerships in order to make everything work again. Don't even bother trying to get this part right with a Chilton's or Haynes manual! Basically, the factory Dodge/Cummins computer and its wiring harness remained intact and got transferred directly to the GMC. From there, the Cummins fuel cut-off relay was supplied with keyed ignition power, and the computer was grounded and fed a constant 12 volts to supply its memory. It's every bit as involved as it looks, which is why the factory wiring diagrams are so critical. Wiring proved to be the slowest part of the swap. McCully purchased factory-wiring diagram With the engine wired, all that was left was to shorten the Dodge radiator hoses (the radiator is now closer to the engine), hook up the intercooler plumbing, and fill the system with coolant. With the engine wired, all that was left was to shorten the Dodge radiator hoses (the radi For a personal touch, McCully added a conical air filter and had Bryon Cipriani of Designit Prototype machine this one-of-none aluminum GMC Cummins valve cover. As we went to press, McCully has been driving his Cummins-powered GMC for a few weeks. He still needs to build an aluminum fan shroud for the radiator, get the stock GMC speedometer, tachometer, and cruise control working, and have A/C lines made to connect the Dodge compressor to the GM system. McCully is also working with Atlas Spring to develop a stronger set of front leaf springs to support the weight of the new engine. For a personal touch, McCully added a conical air filter and had Bryon Cipriani of Designi SOURCES Atlas Spring N/A www.atlasleafspring.com Fabworx Off-Road www.fabworxoffroad.com Designit Prototype www.designitprototype.com Reliable Goods www.reliablegoods.com Enjoyed this Post? 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