From: ddoyle9570@aol.com
Date: Tue Oct 15 2002 - 20:30:36 PDT
The M35A2 is sporty-like compared to the wrecker because the deuce tips the scales at about 12000 lbs, while the wrecker with no load weighs in at about 33000 lbs.
The 5 ton wreckers were originally powered with the powerful but ineffecient Continental R6602 6 cylinder gas engine. With a max RPM of somewhere around 2800 RPM they produce 232 HP. I don't have a torque curve handy, but it has been my experience that somewhere in the 1300-1400 RPM range the torue goes to, oh, 7 million pound feet. If the folks a couple miles away can stand the roar of the exhaust, and the vibration in your chest doesn't make you hyperventilate, a 6602 powered truck will pull whatever it is coupled to. And it will do this at 2 MPG, but it won't do it quickly----even when empty, it won't do it quickly.
In 1960-1963 came the idea of the diesel powered five ton (commonly referred to as the -A1 trucks). These were powered by the 672 cubic inch Mack ENDT-673 engine. 205 hp @ 2100 RPM, 560 lb-ft torque at 14-1600 RPM.
The came the LDS-465-1 Multifuel powered trucks (commonly referred to as the A2 series). These were powered with the 185 hp @ 2600 rpm, 425 lb-ft at 2000 rpm turbosupercharged engine.
Later came the Cummins powered 800 series trucks (as were the 900 series).
Other than ease of starting (nothing starts like a Multifuel), I have never heard anyone say anything good about a Multifuel powered wrecker compared to the gasser. (Ok, well, the fuel cost is much lower.)
But keep in mind that even with the LDS, the truck will do what it is intended. IT is NOT intended to cruise down the road with another vehicle bobbing behind at 50 MPH. It is intended to go into a god-forsaken area, and hook onto a vehicle that is mired or broken down quiet likely in some spot the average person wouldn't dream of going in a normal vehicle, and pull something a relatively short distance. The objective is to hook on and pull. And with the gear ratios available, any of the engines above will do that nicely. If the road/trail is impassable, the top speed the truck is capable of is irrelevant.
As a rule, if the Army needs to move a disabled vehicle a long way, or over highways, they load it on a trailer.
The legendary high-speed "Red Ball Express" of WWII is famous for its rapid movement of military cargo, and the roving patrols using wreckers to keep the motorway clear of disabled vehicles. Did you know that the Red Ball drivers were given strict orders not to exceed 25 MPH? That helps put into perspective how different our expectations of these vehicles are from that which the military expects.
Typically the guys you hear talking about "hot-rodding" a Multifuel engine are doing this to a vehicle that will never, ever see the load the 33000 pound wrecker does everytime it moves, thus are more forgiving to the "modifications" (improvements?) folks make to them.
Regards,
David Doyle
PS: Actual torque rating of the R6602 is 504 lb/ft at 1500 rpm.
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