The Power to Win
Detroit Diesel Division of General Motors in World War Two
Detroit, MI
1938-1988 as part of GM. 
Currently it is the Detroit Diesel Corporation.

This page updated 3-28-2024.

Detroit Diesel World War Two Production:  Detroit Diesel built an estimated 193,000 engines during the Second World War.  These included one, two, three, four, and six-cylinder two-stroke in-line diesel engines.  They were built for military use in four types of tanks and tank destroyers, eleven different types of landing craft, and unknown number of applications providing auxiliary ship's power, engines for stationary generators, tugboat propulsion, and earth moving equipment.  

The only reliable World War Two production numbers available are from the current Detroit Diesel Corporation website, which states that 57,892 engines were built in 1943. General Motors data indicates the Corporation built 198,000 diesel engines during the war.  My research indicates that Electro-Motive and Cleveland Diesel combined built 5,000 diesel engines, which gives the 193,000 estimated for Detroit Diesel.  My research also indicates that the six cylinder 6-71 engine was the major production model of the five sizes used by the military.  Below are tables that show that 43,060 6-71 engines were used in tanks and another 52,525 6-71 engines were utilized in landing craft for both propulsion and ships' power.  This leaves another estimated 95,907 Detroit Diesel engines built during the Second World War where I have not been able to identify the application.  Note that the number of engines provided for landing craft just about equaled a year's production at the rate obtained in 1943.

Detroit Diesel engines were in high demand.  In some cases, as is shown in the Table 3 below, gasoline powered engines had to be substituted by landing craft builders.  Even in far away Australia, the Detroit Diesel was in demand by the Army and Air Force for their 40-foot utility boats.  Only when Detroit Diesel engines became available out of scrapped tanks in the country could they get some.

Detroit Diesel employed around 4,300 employees during the war.

Detroit Diesel Division of General Motors won the Army-Navy "E" Award one time during WWII.

Nomenclature Confusion:  Sometimes in the current literature Detroit Diesel will be referred to as a GM or GMC diesel.  The GMC Truck and Coach Division (Previously Yellow Truck and Coach until mid-1943 was a company in which GM had majority stock holdings.) did not make diesel engines.  Before and after WWII, Yellow Truck and Coach / GMC used Detroit Diesel 6-71 engines in the Silversides Greyhound buses it was making.  GMC or previously Yellow only built gasoline powered engines.  If just identified as a GM diesel engine, it would still be a Detroit Diesel.

General Motors Diesel Power:  GM had four diesel divisions during the Second World War.  Detroit Diesel built 15 to 250 hp diesels, Cleveland Diesel built 150 to 2,000 hp diesels, Electro-Motive built locomotive and some ship diesels, and the Diesel Equipment Division supplied components for the other three divisions.  As can be seen in the ads below, GM combined the marketing of the engine-producing divisions, although the one ad is all about Detroit Diesel producing its 100,000th engine for the war effort.

The basic Detroit Diesel 6-71 engine:  35,351 of these provided the basis for powering 20,855 tanks and tank destroyers as singles or in pairs.  It also supplied 52,525 6-71s as the basic building block for 33,549 landing craft as singles and quads.

This is a view of Detroit Diesel 6046 tank engines coming down the assembly line.  They would be used in the M3, M4A2, and M10.

This M4A2(76)HVSS Fisher Body Grand Blanc Tank Arsenal with serial number 69192 and registration number 30129671, was built in April 1945.  It was powered by the Detroit Diesel 6046 engine.  It can be seen outside the Beatty Street Drill Hall in Vancouver, BC.  It was one of 7,508 M4A2s built by Fisher Body.  Photo courtesy of David Jackson, Jr.

This is one of 4,993 M10 Tank Destroyers.  It was powered by two 6-71 225 hp diesel engines driving one driveshaft designated the 6046 that was built by the Fisher Body Division of GM at its Tank Arsenal in Grand Blanc, MI.  Fisher Body-built M10s were deployed overseas while the Ford-built M10A, with a gasoline engine, stayed in the US during the war.  Consequently, any M10 seen in a photo in combat in Europe or the Pacific was powered by Detroit Diesel.  This is one of 1,648 that was provided to the British during 1944 and 1945 and is also one of 1,017 that was converted to an M10C with a British 17-pounder main gun to replace the original 3 inch gun.  The 17 pounder can be identified by the long barrel and the distinctive muzzle brake.  As this was a British operated M10C, the US stars on the vehicle are incorrect.  Author's photo from the Bastogne Historical Center in Belgium added 10-12-2015.

The Free French army in Europe operated 255 Detroit Diesel powered M10s and the USSR received fifty-two of them in 1943. Author's photo added 10-12-2015.

This is one of 3,981 Valentine tanks built in both Canada and Great Britain that used a Detroit Diesel 6-71 engine.   Author's Photo from the Canadian War Museum added 1-8-2017.

The Landing Craft, Vehicle Personal (LCVP)

The LCVP or the Higgins Boat, as named after its inventor Andrew Jackson Higgins, was considered by Dwight D Eisenhower to be one of the most important weapons of World War Two.  With its low draft, which allowed it to come right up on to the beach, and its innovative front drop ramp let the assault troops exit forward right onto the beach.  With the previous type of landing craft, it was difficult for the troop to climb up over the sides with heavy combat packs.  Then, jumping onto the beach or into the water near the beach could bring broken bones or drowning.  While its concept seems obvious, in retrospect it was truly a game changer for allied forces.  (Actually, it was based on Japanese landing craft that already had a ramp in the front of the craft.) 

23,353 LCVPs were built in the United States during World War Two by Higgins Industries, Chris-Craft, and four other companies.  The one shown above was built by Higgins and is one of only eight original LCVPs built during World War Two still in existence.  What makes this LCVP significant, owned by the Roberts Armory in Rochelle, IL, is that it was one of the 19,353 that came equipped with a Gray Marine/Detroit Diesel 6-71 engine.  Charles Roberts, owner of Roberts Armory, a private museum, has done a remarkable job of restoring this all wooden vessel to the way it looked when it was built in 1945.  Author's photo added 9-18-2015.

The LVCP was 36 feet long, made of plywood, and could transport 32 infantrymen directly to the beach.  The engine was at the rear of the craft.  Charles Roberts allowed me to photograph the engine bay with its Gray Marine/Detroit Diesel 6-71 engine when I visited the museum on Memorial Day, 2015.  Due to high winds, he did not take the tarp off completely as he normally does to let the public look at the landing craft.  I thank Charles for taking the time to show me and let me photograph the engine.  Author's photo added 9-18-2015.

Standing in the right rear of the engine bay, the coxswain's station with steering wheel, the throttle, and a few gauges were first to be photographed.  Note that there is a simple throttle linkage that runs across the front of the engine, in front of the water to water to water/alcohol heat exchanger.  Then it connects to the governor on the side of the engine.  Author's photo added 9-18-2015.

The governor has two settings, "Normal" at the right top, and then "Battle" which is partially obscured by the shadow of the set screw shadow.   Author's photo added 9-18-2015.

The front of the LCVP and engine are to the right.  At the bottom of the photo is the air intake and filter, then the Roots supercharger with a Delco-Remy Plant Five rotor, the engine block, and then on far side the exhaust.  Author's photo added 9-18-2015.

Looking from front to back one can see the name Gray Marine on the front.  While Detroit Diesel provided the operating engine, Gray provided the water to water/alcohol heat exchanger with its name on it.  Over 95% of the content of the engine was provided by Detroit Diesel.  Author's photo added 9-18-2015.

This view is looking down at the rear of the engine with the fuel system on the left and the exhaust on the right.  Author's photo added 9-18-2015.

This photo looks down at the back of the engine from the right or starboard side of the LCVP.  Author's photo added 9-18-2015.

The Gray Marine 64HN9/Detroit Diesel 6-71 Marine Engine:  In looking at the literature that describes the type engines used in many of the landing craft of the Second World War, they are described as a Gray Marine 225 hp diesel engine.  Gray Marine Motor Company in Detroit, MI modified Detroit Diesel 6-71 engines for marine use on landing craft by adding a transmission and a heat exchanger as the central part of the cooling system.  Gray also added a governor, air intake with silencer, and a flywheel assembly to power such items as a bilge pump in the boat.  Because Gray was the last company to "touch" the modified Detroit Diesel 6-71 engine, it was identified as the builder.  However, Detroit Diesel built up the engines in its plant and probably had 90% of the value in the final product.  Therefore, in the information on this page I have designated it as the Gray Marine 64HN9/Detroit Diesel 6-71, to show that Gray modified the Detroit Diesel 6-71 engine.  They both get credit for their portion of the final product. 

Also, the current literature shows the Gray Marine 64HN9/Detroit Diesel 6-71 as a 225 hp engine rather than the 238 maximum hp shown in the table above.  The 225 hp was a net hp rating.

This is the original Quad Four Engine that was originally developed by Electro-Motive Division in LaGrange, IL in February 1942.  After it was proven feasible, Detroit Diesel picked up the manufacturing for use in the LCI(L) and LCS(L).

An LCI(L) that used two 6051 Quads for eight 6-71s.  They provided propulsion to two propellers, and then two more Detroit Diesel 6-71s, running generators to provide electrical power for the rest of the ship's power.  The LCI(L) could carry an entire army infantry company and deliver it to the beach, ready for combat as a unit.

Here, an LCT unloads its cargo including a GMC 2-1/2 ton CCKW truck on the beach.  The LCT got to the beach powered by three Detroit Diesel 6-71 engines driving three propeller shafts.

1,052 Landing Ship Tanks (LST)  each utilized three 6-71 Detroit Diesel engines for ship's power.  Half of the LSTs had propulsion provided by GM's Electro-Motive Division.  This is the only LST still operating.  LST-325 is seen here just a mile downstream from her berth along the Ohio River in Evansville in June of 2015.  Author's Photo added 10-12-2015.

Here are two of the three 6-71 ship's power engines on LST-325 in Evansville, IN.  Part of the tank level deck has been cut open so visitors can look down to see the engines inside the auxiliary engine room.  The hole is covered with Plexiglas for safety reasons, but also impairs clear photos of the engines.  The orientation is looking towards the front of the ship.  The engines, the electric generators, and the controls can be seen for two of the engines.  The third engine to the right or starboard side of the ship is now a newer Cummins diesel that currently runs power for the ship.  Author's photo added 6-22-2018.

 This is looking at the port side of the middle 6-71.  The name Detroit Diesel can be seen on the valve cover.  Author's photo added 6-22-2018.

This is looking at the starboard side of the port 6-71.  The name Detroit Diesel can be seen on the valve cover.  Author's photo added 6-22-2018.

Author's photo added 6-22-2018.

The name Detroit Diesel can be seen on the valve cover of the port engine.  Author's photo added 6-22-2018.

This ad has an artist's rendition of one of the 1,052 LST's that were equipped with three Detroit Diesel 6-71s for ship's power landing an M10 Tank Destroyer that was powered by two Detroit Diesel 6-71s.  All M10s deployed overseas were powered by the 6-71 engine.

Detroit Diesel Fights
This 42 page booklet published by Detroit Diesel in December 1943 states in its own words how it is contributing to the winning of World War Two.