SC Diesel Repair & Performance Owner Evan Schuster (right) with, from left, technicians Evan Breheim and Jordan Brown, show off the block for a 6.7-L Cummins the shop is building to 1,200 HP for a street/strip shortbed Dodge.Technician Evan Breheim disassembles parts to prepare for removal and installation of a 6.7-L Cummins engine in a Ram pickup.Technician Will Nichols works on removing a transmission on a Ford Power Stroke pickup.Fords make up many of the trucks worked on at SC Diesel Repair & Performance.

Not just blowing smoke

SC Diesel Repair & Performance’s repairs boost power but also increase reliability and fuel economy

Boonville, Mo.—Sometimes you can have your cake and eat it, too. Those accustomed to pumping up gasoline engines’ output are aware of how, as performance goes up, reliability and fuel economy often go down. But owners of diesel light trucks needing major engine repairs can get better fuel economy and reliability and gain much-appreciated towing power, said Evan Schuster, owner of SC Diesel Repair & Performance.

“A lot of general repairs go hand-in-hand with performance,” he said. “There are many factory flaws you can fix and, in doing that, you can add performance instead of putting it back to 100 percent factory and ending up with the same issue. For a 6.4 Power Stroke engine, if you rebuild it back to factory bone stock, you just have another ticking time bomb, and it will go another 100,000-120,000 miles before you put another engine in it.”

The 6.4-L Power Stroke, in particular, has a number of parts that are highly stressed and failure-prone in factory form, often suffering problems such as cracked pistons and valvetrain failures.

“The camshafts are designed for a lot of EGR flow, so that messes up the valvetrain geometry,” he said. “That chews up the rocker tips, and then it chews up the dogbones.”

The new stage-one camshaft that SC Diesel installs not only corrects the valvetrain geometry issues, it adds about 40 to 50 HP, he said.

“Whether it’s Chevys, Dodges, or Fords, a lot of the issues are emissions controls-related,” he said. “None of them work worth a damn unless you’re on the highway a lot, with higher RPMs and higher temperatures. In-town driving is harder on all that stuff.”


More electronics require advanced diagnostics

Although he cut his teeth on mechanical fuel injection, Schuster likes the diagnostic capabilities of modern high-pressure common rail electronics. “But you still have to apply basic diesel engine principles: fuel and air make the diesel engine go down the road,” he said.

Dealership-level scan tools tend to be user friendly compared to aftermarket scan tools, but with subscriptions for the Dodge factory scan tool costing $3,000 per year, they are not cost-effective for him, he said, since he does little reflashing. He does maintain a Ford IDS scan tool, as its $800 annual cost is more reasonable, and he works on a lot of Fords.

So the Snap-on Modis handles most diagnostic duties, paired with an Identifix subscription, which can often point to fixes for common problems without time-consuming flowchart step-by-step procedures. At the same time, Schuster said young technicians often don’t know how to look beyond the codes a scan tool is telling them. A number of sensors share a 5-volt supply circuit, so when there is a fault with one, it can appear to be a problem with another. He recalled an example of a Ford truck that was first at a dealership, where the DTC pointed to a bad throttle position sensor. The dealer technician replaced the throttle pedal and tried some other fixes over a couple of days. Using Identifix and doing an inspection, Schuster found the common problem — a hose lying on the exhaust back pressure sensor wires had rubbed the insulation bare, shorting the sensor.

“So his truck was at the dealership for several days, with several hundred dollars spent, with no problem fixed. I put a $15 pigtail on it, and a half-hour later, I was telling him to have a good day.”

Dodges/Rams have more problems with transmissions than with their engines, Schuster said, and for rebuilds, the prescription is additional clutches with upgraded friction material and valve body modifications to increase line pressure for greater clamping ability. Replacement torque converters feature an upgraded stator and clutch mechanism, and a heavy-duty billet front cover to replace the flex-prone stamped-steel cover. Although his shop has been having transmissions rebuilt locally, Schuster will soon be doing them in-house, after he attended a class last spring at a Florida manufacturer to learn the ins and outs of the Dodge 48RE transmission.

Joined at the shop by four technicians, an office receptionist, a truck salesman, and his wife, Amber, Schuster started his business in late 2010 with a friend in a small rented space in Columbia. He soon took over the business as the sole owner, later moving and expanding his footprint several times. Earlier this year, he made the shop’s new home an 8,000-square-foot building that can comfortably fit eight trucks, with three overhead doors for better access.

Schuster joined the NAPA AutoCare program a few years ago, and with his shop’s high-visibility I-70 location, the nationwide program is a confidence-booster for customers.

“It is nice to know that if you get your truck worked on here, there is backing to it. If you get to Los Angeles and we put brakes on or whatever on your truck and something goes wrong, you’re going to be able to get it fixed out there by another AutoCare center. They’re going to stand behind it.”

Parts & People

Parts & People is published monthly by Automotive Counseling and Publishing Company, Inc., a Colorado corporation, P.O. Box 18731 Denver, CO 80203, 303-765-4664. President-Lance Buchner. Founded by Lance Buchner and Dave Lucia.