Utah Shop Replaces Customer’s Engine After Finding Its Own $20,000 Assembly Error

A Utah diesel shop tore apart a customer’s blown compound-turbo engine expecting to find evidence of abuse. Instead, the owner discovered a mistake his own builder had made, one small enough to miss during assembly, catastrophic enough to destroy the entire motor two years later.

Dave’s Auto Center, a family-run operation out of Centerville, Utah that’s been turning wrenches since 1990, had built a heavily modified diesel for a customer named Eric. Compound turbos, performance pistons, ARP hardware, race bearings, the kind of build where you tell the customer upfront that nothing is warrantied, because extreme cylinder pressures can wreck parts through no fault of the shop’s labor.

When the engine came back in pieces roughly two years after delivery, the shop’s working assumption was fair: Eric had over-boosted it. The system could theoretically hit 100 PSI. The carnage inside the block looked like a grenade had gone off. Nobody was rushing to hand out a free engine.

The shop charged Eric to pull the motor and began tearing it down methodically, half-expecting to close the file as a customer-caused failure.

During disassembly, a technician noticed something wrong with one of the connecting rods. The rod bearings specified for the build were of a gun-drilled design, which relies on a small internal channel bored through the connecting rod to deliver pressurized oil from the crankshaft journal directly to the wrist pin bushing.

The bushing had been installed correctly. The hole through the bearing to actually feed it with oil had never been drilled. Floating wrist pins require pressurized oil delivery to maintain their extraordinarily tight two-to-three ten-thousandths-of-an-inch clearances, and without it, the pin ground to a halt inside its bushing.

The rod couldn’t move. The engine’s own torque bent the connecting rod, fractured components throughout the block, and punched a hole through the casing. The shop owner’s assessment on camera was blunt: “The builder overlooked drilling a hole. ” The builder in question had already left the shop more than a year before the teardown.

That detail didn’t change anything for the owner’s decision.

The replacement build swaps in a different connecting rod specification that routes wrist pin lubrication through splash oiling via dedicated squirters rather than gun-drilled passages, cutting off the failure mode entirely. The teardown also turned up cracked rocker pedestals and broken rocker bolts throughout the stock valve train, a separate issue the owner attributed to increased valve spring pressure from the performance build, so the replacement gets a Jessel valve train system as well.

Before going back in the truck, the completed motor will run on the shop’s sim-test machine and then get load-tested on a chassis dynamometer. The shop owner used the incident as a live case study while announcing the promotion of engine builder Mikuel, on staff for about a year and a half, into a formal builder role.

His stated top qualification for the position had nothing to do with machining credentials. ” The answer to that question, he argued, determines whether a shop grows or eventually chokes on its own corners.