Building The Perfect Truck

Dodge chassis topped with Chevy cab

January 2019 Cummins, Feature Steve Janes

Andrew Munster

Whistler, BC

1969 Chevy C30 w/Cummins Supercharged Turbo

 If you’re working for a living, you may as well focus your work on something you love doing. For Andrew Munster of Whistler, BC, combining work with snowmobiling was a natural fit. And custom-building a truck that helps get him from home to work to the mountains just made sense.

“The truck is a purpose-built sled hauler,” Munster explained. “It is designed to hold two sleds side by side, and get me around to local riding areas. “

Since this truck was also his daily driver, it was designed specifically with drivability and ease of use in mind. “I only just finished building my current truck in September,” he said. “It is a 1969 Chevy C30, but a Dodge 2500 at heart.”

Munster has been driving diesel trucks for the past 10 years. His first diesel truck was a 95 Dodge Cummins 2500.

“I have been in love with the 12-valve ever since,” he explained. “I have owned five different Dodge 2ndGen 12-valves and one Dodge 24-valve, just to try it.” 

Munster, 32, grew up in the Whistler area. His parents have lived in the area since the early 1970s and made a living by building custom homes when Whistler was going through a growth spurt. His focus in school was business and sciences … but he spent his winters on skis and snowboards before he got hooked on snowmobiling. He has always made winter sports his top priority.

He worked for seven years as a heavy equipment mechanic before setting up his own fabrication/machine shop. “In the summer I have always loved working on projects—building, fabricating and machining anything that interests me. But in the wintertime my life is sledding.”

Perhaps that is why his business naturally progressed to a company that manufactures and sells aftermarket parts for snowmobiles. “We specialize in making performance parts and accessories specifically for mountain snowmobiles,” he explained. “Mountain sledding is my passion.”

So what inspired Munster to custom-build a truck specific for hauling snowmobiles?

“I have been modifying vehicles since before I could drive. My first big project was a ‘69 Nova I started restoring when I was 16. After that, I got into modifying Chevy 4x4’s and it wasn’t long before I discovered the Cummins Diesel.” 

But with his business making aftermarket performance parts for snowmobiles, Munster needed something that could make it easy to get to snow during early and late seasons when you needed to drive up tight mountain roads.

“The project started out as a 1998 Dodge Cummins 12-valve rolling chassis,” he said. “It was originally a manual extended cab short box.”

Munster than scrapped the rear Dodge leaf springs, shortened the wheel base slightly and built his own truck arms and panhard bar. “I wanted to have air ride in the rear so the truck will ride nice when it’s empty and I can air it up when I have sleds on,” he explained. “I thought I might as well do the front air ride as well, so I bought a front air ride kit from Kelderman and additional bags for the rear.”

To finish it off, Munster had Filthy Motorsports build him a custom-valved set of King 2.5 Smoothie shocks. To run on board air, he converted the stock AC pump to a grease lubrication system so it could be used as a compressor pump. The air ride control is inside the cab. There are two gauges with four needles that read psi, and each corner can be adjusted by pneumatic switches.

Munster said the engine and 5-speed transmission were completely stripped down and rebuilt. The transmission was built with new synchros and bearings. “I made sure to shim the bearing lash a little bit on the tighter side of the recommended tolerance,” he explained. “The Cummins motor just seems to amplify any slop in the drive train and my goal was to make this truck as tight feeling as possible. Of course, the fifth gear nut was fixed with a splined nut retainer, and the  fifth gear itself was replaced as well.”

Since the output shaft splines were in good shape, Munster said he didn’t bother to upgrade the shaft. However, he bought a South Bend clutch kit that came with a new flywheel since he wanted to get a clutch that could handle the extra horse power, but still have a light foot pedal disengagement.

Next, the engine block was sent out for machining where it was magnafluxed, honed and decked. The valve seats in the head were machined and stiffer exhaust valve springs were installed to accommodate a different exhaust brake.

Munster then rebuilt the bottom end with all new bearings and installed new Mahl pistons.

“I also installed a high flow oil pump that comes on the 24-valve to get a little more oil pressure,” he said. “The head was bolted down with ARP head studs and a .010-inch oversized Victor head gasket was used to make the clearance I needed after decking the block.”

The injection pump was sent out to NW Fuel Injection where it was fully rebuilt and retimed. The timing was set to 15 degree total advance and the governor was set to 3,000 rpm. The stock 215 injectors were also flow tested to make sure they were in good shape. The pump was tuned to move 320cc of fuel at full boost, which is a mild 400 horsepower or so.

“My plan was to make a very reliable and drivable 400 horsepower with low EGTs,” he said. “Now that I had the basics covered, I installed a BD Stainless Exhaust manifold and an AST Aurora 3000 Turbo.”

Munster said he did a lot of research on what turbo to choose, and went with the Aurora 3000 mainly because it fit into a good efficiency range with the horsepower he was going to be making, and still had a fast spool-up.

“Another benefit to the Aurora 3000 is it doesn’t have a waste gate, which made it the perfect partner with the supercharger I planned to bolt on before it,” he explained.          To make the truck really shine in the drivability category, Munster managed to make room for a Procharger D-1SC by moving the alternator on top of the engine and putting the Procharger in its place.

“A centrifugal supercharger has an exponential boost curve which made it a good candidate to keep up with the turbo,” he said. “I have seen some positive displacement chargers used on diesel engines in the past, and in most cases it seems to be a restriction once the turbo starts building boost and moving a lot of air.”

Munster said his main concern with the Procharger was getting it to spin fast enough to keep up with the turbo, especially when the Cummins engine spins at such a low RPM and the Procharger is only driven off the main 8-rib serpentine belt.

“This was all a big experiment to say the least,” Munster said. “Nobody seems to make pulleys for the Procharger small enough for my application, so I started making my own on the lathe.”

After making three different sizes, Munster finally got some good results. “Surprisingly, even at the largest pulley size I tried, the supercharger would supply positive pressure to the turbo all the way through the rpm curve regardless of how much boost the turbo was producing,” he said. “Almost like the centrifugal force of the Procharger would make a set pressure to the turbo based on rpm alone.”

The engine load, CFM and turbo boost pressure seemed to make very little difference to the boost the supercharger was supplying to the turbo. After making a small enough pulley to reach the boost numbers Munster wanted, the truck started to drive more like a supercharged car than a laggy turbo diesel.

“This is easily my favorite mod to the truck by far,” he explained. “Under full load the supercharger will reach numbers of about 10 psi supplied to the turbo, and the total boost pressure of the turbo will hit just over 50 psi, with EGTs just barely scratching 1100 degrees.”

Next, Munster mounted a Pac Brake exhaust brake. “I mounted a button on the shifter so I can engage the air actuated exhaust brake on the fly,” he said. “The switch I used is a snowmobile kill switch that I manufacture.”

After the Dodge 2500 chassis was complete with the rebuilt suspension, Cummins engine and drivetrain, Munster started fitting the C30 cab onto the Dodge chassis.

“The cab came off of a 1969 Chevy C30 motorhome that I acquired with only 26,000 original miles on it,” he explained. “The exterior of the cab was in great shape, but I still had to do a fair amount of rust patching around the rockers and floor pans.”

Munster then replaced the ‘69 front end with a ‘67 style hood, grill and fenders.

“Fitting the Chevy cab to the Dodge chassis wasn't an easy feat,” he explained. “The Dodge front end stuck out much farther than the Chevy, so in order to line up the front wheel with the wheel well of the Chevy cab, I had to cut the front of the Dodge frame shorter and make all new front bumper and cab mounts.”

Now that the grill of the Chevy cab was much closer to the motor, Munster had to move the motor back about three-quarters of an inch and build a whole new radiator and intercooler support.

“There was no room left for the stock fan,” he said. “So I mounted a high flow small electric fan offset from the motor so it would fit.”

The steering and brakes were fairly easy to adapt. Munster only had to do minor modification to the Chevy steering column in order to mount it to the Dodge steering box.

“The whole brake and clutch pedal assembly unbolts as one unit from the Dodge, so I was able to remount it to the fire wall of the Chevy cab, with the master cylinder and all,” he said. “The only mechanical components I ended up keeping from the C30 are the steering column and park brake assembly.”

Finally, Munster added an aluminum flat deck, a product he has built for his snowmobiling customers. “This is a version that I tailored and designed specifically for this truck,” he explained. “Part of the reason for getting rid of the leaf springs was to be able to make deep tool compartments that go right to the frame. Because of the single cab, I needed lots of extra room for storage.”

The compartments are fully sealed. Munster built a heat exchanger on the bottom of the compartments which cycles engine coolant to heat the boxes in the winter. The top deck was designed so the cleats for clamping snowmobiles can be adjusted and removed if needed to put something flat on the deck. The aluminum sled ramp fully tucks away in the back of the deck and pulls out for easy loading.

Munster figures that between two donor trucks, parts and paint, he has spent about $55,000 on the truck and has well over 1,000 hours of time into it.

“I did almost all of the work on the truck myself, with the exception of paint,” he said. “I have painted enough of my own vehicles in the past to learn to just leave it to the professionals.”

Since daily driving was the top priority, most of the changes Munster did to the truck were to improve comfort, drivability and ease of use. “I wanted to make hauling sleds around as easy as possible, ultimately making sledding more enjoyable.” 

Munster said the engine and drive train improvements seem to be the most significant features of the truck. “The engine feels very responsive and tight. The suspension is also very firm and the truck handles like a dream. I am very impressed with the way it drives,” he explained.

As for the flat deck, Munster said it is ideal for sled transport because it’s lower than a traditional sled deck, which makes it easier for loading. “You can still fit two sleds side-by-side, but the cab shelters them so they don’t get caked with dirt on the highway.”

Having the sleds on the truck instead of towing a trailer is mandatory when exploring roads and trying to find new access points, Munster explained. Most riding zones in BC are accessed by driving up rough and narrow logging roads with limited parking. The truck itself should do great up the logging roads.

“I plan on installing an ARB Rear Air locker in the near future to help with trenching through snow patches … and maybe the odd burnout,” he said.

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