Ford began to offer diesel engines in its heavy-duty F-Series trucks and Econoline vans in 1982. Because of their hauling capability and durability, diesel engines have become popular with people who frequently haul heavy loads or travel long distances with their trucks. The 1991 7.3 diesel was among the second generation of Ford diesels. On some sites you may see this engine described as a Power Stroke Diesel. Though the computer-controlled direct injection Power Stroke technology was originally a modification of this engine, it did not debut until 1994.
Size and Configuration
The 7.3-liter engine is made of cast iron and is in a V-8 configuration. In displacement, 7.3 liters are equivalent to 444 cubic inches. It weighs approximately 920 lb. Often you will see it listed as the 7.3 IDI Diesel. The IDI stands for indirect diesel injection, which means that fuel is injected into a pre-chamber before entering the combustion cylinders.
Horsepower is a measure of acceleration from a standing stop to top end speed. The 1991 version of this diesel reached 185 horsepower at 3,000 rpm. In 1993 an aftermarket turbo kit was introduced that will raise the horsepower to 190. This compares to the 275 horsepower at 2,800 rpm in the later Power Stroke version of this diesel.
Torque is a measure of a vehicle's pulling power --- and is a major reason many truck buyers prefer the superior torque of diesel engines. The 1991 version of this diesel produces 360 ft-lb of torque at 1,400 rpm, which the aftermarket turbo will boost to 388 ft-lb. Because the peak torque is reached at much lower rpm than gasoline engines, a diesel can pull heavy loads without as precipitous a drop in fuel economy as in gasoline engines. The later Power Stroke version of this engine produces 525 ft-lb of torque at 1,600 rpm.
It is not miles that age an engine, but rpm. Because diesels reach their peak power levels at much lower rpm than gasoline engines and because of their heavier construction, diesel engines can be expected to last about 350,000 miles before needing overhaul. That compares to about 125,000 miles for gasoline truck engines.
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