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Originally Posted by freebeard
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Rarity and weight. A big block Chrysler was the heaviest. 750-lbs bare long block. Close to 900 dressed.
A 5.9L Cummins is past 1,100-lbs bare. These tank motors well past that. Thus a custom frame and front end. Then all other drivetrain parts customized as well. Medium and heavy-duty truck parts. THEN suspension and steering.
The only “light” reference with these tank engines is packaging and weight versus comparable diesel. Along the way in tank development were dual engine models.
It’s an engine type desired by commercial operators of rail switch engines and barge tugs. I doubt there was ever the necessary aftermarket support. High TQ and low HP demands a heavy, complex transmission. Engine meant to run in a narrow rpm band continuously. Not stop & go.
Despite the movies, a tank is just a way to move a heavy gun with armor protected crew to another location. Infantry had protection on the move, but it was WHERE to set that armored gun that mattered. Tanks are a great way to destroy or defend logistic choke points. Railyards, river crossings, etc. The engine will spend more time running in situ to power the weapon.
Gasoline was our military choice because we had so much of it. Airplane fuel also. Our crude oil stocks were ideal to refine gasoline (diesel not so much). It’s a far cheaper/lighter engine to build. Thus, field swaps possible. Not so with diesel.
But turbines don’t want gasoline, and obviously not diesels. We skipped diesel development in some ways (xtra heavy) as we knew turbines were the future. Naval ships, airplanes, mobile armor. Your daddy was meant to be the beta tester for auto turbine engines that later could be adapted for military. (Light aviation also). Turbines had (have) applications still not filled given simplicity plus very high power-to-weight ratio.
In the late 70’s and early 80’s saw development of wheeled Army land vehicle engines that were multi-fuel. Could be moved from one theater to another more easily. Could use that theaters less desirable fuel. Chicken & Egg problem. These were modified diesels.
The CUMMINS/WESTERBEKE dual-fuel engines are that continuation (using CNG).
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