1674 DIESEL TRUCK ENGINE General Information Caterpillar

General Information

The 1674 Diesel Truck Engine is a 638 cu. in (10,5 ltr.) displacement, 4 stroke cycle, 6 cylinder turbocharged and aftercooled engine. This dual overhead cam engine with a 4 valve per cylinder design is made especially for highway trucks hauling big payloads. Serviceability is featured by spin-on throw away fuel filters, easy valve adjustment, replaceable cylinder liners and valve seats, and piston and rod removal from the top.

Individual injection pumps, one for each cylinder, meter and pump fuel under high pressure to an injection valve and a precombustion chamber for each cylinder. An automatic variable timing device advances or retards fuel injection and is regulated by engine speed. The faster the engine turns the earlier the injection must take place before piston top center on the compression stroke.

A hydro-mechanical governor controls the fuel injection pump out-put to maintain the engine RPM selected by the operator. A speed limiting device, in the governor, limits engine speed until engine oil pressure builds up.

Inlet air, filtered by an air cleaner, is compressed by a turbocharger before entering the engine cylinders. The turbocharger is driven by the engine exhaust.

There are four in-head valves (two inlet and two exhaust) for each cylinder. Two overhead camshafts, and forked rocker arm assemblies, are located in a housing on top of the cylinder head. The forked rocker arm assemblies act as a direct mechanical link between the lobes on the camshafts and the valve stems. The timing gears are located at the rear of the engine.

Coolant for the engine is used to cool the engine lubricating oil. A full-flow temperature regulator, in the cylinder head at the front of the engine, provides for quick engine warm-up, and allows free circulation of coolant after operating temperature has been reached.

Lubrication for the engine is supplied by a gear-type pump. The pump provides full pressure lubrication to the engine internal and external parts.

The lubricating oil is both cooled and filtered. By-pass valves in the oil cooler assembly provide unrestricted flow of lubrication oil to the engine parts when oil viscosity is high or, if either the oil cooler or the oil filter element should become clogged.

The starting system is direct electric and uses a 24 or 12 volt starting motor.

Efficiency of emission controls and engine performance depends on adherence to proper operation and maintenance recommendations, and use of recommended fuels and lubrication oils. Major adjustments and repair should be entrusted to your authorized dealer. Follow the recommended maintenance schedule with special emphasis on fuel injection nozzles, air cleaner, fuel-air ratio control and high and low idle adjustment. Fuel-air ratio control and the high and low idle adjustments should be made by an authorized dealer.