Engine: Description and Operation

The 73L diesel engine is:
^ a four-cycle turbocharged V-8 with overhead valves.
^ 7.3 liter (444 cubic inch) displacement.
^ separated into two banks, the right bank numbered 1, 3, 5, 7 and the left bank numbered 2, 4, 6, 8.
^ rated at 215 horsepower at 3000 rpm.

The cylinder block has been designed to withstand the loads of diesel operations by using:
^ four-bolt main bearing caps.
^ internal piston cooling oil jets.
^ a forged steel crankshaft.
^ heavy-duty forged steel connecting rods.

The piston and rings are:
^ made of aluminum alloy.
^ fitted with an upper keystone compression ring.
^ fitted with a lower rectangular compression ring.
^ fitted with oil control rings.

The piston pins are:
^ a free-floating type permitting the piston pin to move/float freely in the piston pin bore.
^ retained in the piston and rings by piston pin retainers.

The camshaft is:
^ supported by five insert-type camshaft bearings.
^ of the roller camshaft design.
^ driven by the crankshaft through the use of the crankshaft gear and the camshaft gear.

The hydraulic valve tappets:
^ minimize engine noise.
^ maintain zero valve lash.
^ incorporate camshaft follower guides.
^ incorporate a roller follower design that reduces camshaft wear.

The cylinder heads are designed:
^ to incorporate electronically controlled/hydraulically actuated fuel injectors.
^ to locate the fuel injectors in the center of the combustion chambers between the rocker arms.
^ With integral high-pressure oil galleries.

The glow plug system is:
^ designed to preheat the cylinders for faster cold weather starts.
^ controlled by the Powertrain Control Module (PCM).
^ mounted directly into the cylinder heads.
^ activated by the glow plug control module.

The optional block heater is:
^ designed to heat the engine coolant and oil for improved cold weather starts.
^ located near the oil filter in the oil cooler.
^ powered by a 120-volt external power source.
^ replaceable but not repairable.

The fuel injection system used on the engine:
^ is controlled by the powertrain control module.
^ utilizes an electric inline fuel pump.
^ circulates through a combination fuel filter, fuel heater and water separator assembly.
^ uses eight electronically controlled/hydraulically actuated fuel injectors.
^ maintains operating pressures between 275-448 kPa (40-65 psi).

The engine lubrication system:
^ is divided into two systems: the low-pressure system lubricates the engine, the high-pressure system actuates the fuel injectors.
^ maintains pressures between 0-414 kPa (0-60 psi) for the low-pressure system and 4137-20,685 kPa (600-3,000 psi) for the high-pressure system.
^ is cooled by an engine oil cooler.
^ utilizes an oil pressure sensor and an oil pressure regulator.
^ actuates the exhaust back-pressure warm-up system integral to the turbocharger.