Truck Topics

A Visit to Detroit Diesel

Wow - what can I say first? We delivered a load just south of Redford MI the other day and we called Miguel Soetaert, Group Leader - Component Optimization, the guy with Detroit Diesel who is helping us with our new truck specs, to see if he had time to see us on such short notice. Sure enough he did, so we headed to Redford where we were met at the truck by Miguel. After getting our visitors badges and safety equipment we were met by Pam Esshaki, Assembly Quality Coordinator - Plant Tours, who would lead us on a plant tour, which we were not expecting. Pam is a wonderful person who is very knowledgeable about Detroit Diesel, its engines, and its history, as she has been there 30 plus years after starting in the trenches at 17. We spent a few minutes getting acquainted and then we were off to see the line.

Wow - this is an awesome factory – assembling engines, doing all the machine work necessary and having research and development under one roof. The roof by the way was raised 12 feet a few years ago to allow the use of new technology equipment. We were all over the plant and this place was spotless. It was simply amazing.

We started with a bare block being installed onto a robotic cart that the engine will stay on until it is completely assembled. The carts follow a path on the floor that uses electromagnetic technology to get from one station to the next. Any worker along the line can stop the line if they feel there is a problem that needs to be addressed or if defective parts are found. These workers have a lot of pride in their work and the product they are creating. There is also a very high level of accountability in their work.

Workers are trained to do several jobs in the assembly process so they can tell if a mistake has been made along the line. When a worker has made a mistake it is caught by another worker or the computers along the line. This worker is then counseled and then re-trained as NO defect is their goal.  Every major part has a dot matrix on it so the computer system can tell you at any given time in the future who installed the part at what time, on what day, and what vendor supplied the part.

The block is then inverted; the main bearing caps are removed and placed on a cart that follows the engine, and the bearing shells are installed in the block and the caps; on to the next station.  The crank shaft is then installed, the main bearing caps put back on and the main cap bolts pre-torqued. On to the next stop. The piston and rod assemblies are then installed one at a time after each rod is connected to the crank shaft and it is pre-torqued. The new rod is then checked for side clearances by hand; while we were there one rod could not be moved.

That piston and rod assembly was removed and a new assembly was installed. This new rod had the same problem, so out of the assembly line the engine came, where a quality control person and the original installer of the piston and rod assembly then removed the piston and rod assembly to be inspected for defects. In this case it was the bearing shell that was defective. The new shell was installed, piston and rod assembly was then installed, pre-torqued and checked for play.  All was well.  This process was recorded and the engine was put back in line for completion. 

After the pistons were installed the block was turned upright and the cylinder head assembly was installed then the engine was off to the torquing chamber. This station is totally computer controlled, after reading the dot matrix, the computer determines which engine it is torquing and adjusts itself to the proper sequence and the torque spec. The head is then torqued to spec then re-torqued as an additional check. If any bolt does not torque to spec or “feel” right to the computer, the line is stopped and the problem is sorted out.

The next stop is for main and rod torquing; as before the computer determines which engine it is working on from the dot matrix then goes to work.  Main caps first in sequence, then the rods one at a time, rotating the crank a full revolution before going on to the next.  This rotation allows the computer to check rotation resistance. If it is too high, all progress stops. Next the crankshaft endplay is checked by the computer. The engine we were following went right through with no problems as most engines do.  On to final assembly, where the cam shafts, rear gear train, fly wheel housing, fuel systems, oil systems, water cooling systems and other external components are installed.

The new Detroit Diesel engines are designed to be very quiet and it was amazing to see how this was engineered into the block and the components. On the new DD engines, 48% of their parts are interchangeable. The oil system only has 8 bolts that hold it on and the fuel system only has 6 bolts. 

After taking this tour, my reasons for having a Detroit engine for my next truck are reinforced.  Every engine coming off the line is test run to operating temperature under a load, and horsepower and torque are checked per engine spec. The engineering that went into these engines is phenomenal - performance, durability and ease of maintenance/repair. All serviceable components are above frame level except the starter. 50,000 mile oil change intervals, accessibility of filters, belts, and other maintenance items – My kind of engine.