Engine: Description and Operation

The Oldsmobile four stroke cycle diesel engine is basically the same in construction as the Oldsmobile gasoline engine. The cylinders are numbered 1, 3, 5, 7 on the left bank and 2, 4, 6, 8 on the right bank on 8 cylinder engines or 1, 3 and 5 on the left bank and 2, 4 and 6 on the right bank on 6 cylinder engines. The firing order is 1-8-4-3-6-5-7-2 on 8 cylinder engines or 1-6-5-4-3-2 on 6 cylinder engines. The major differences between the diesel and gasoline versions is in the cylinder heads, combustion chamber, fuel distribution system, air intake manifold and method of ignition. The cylinder block, crankshaft, main bearings, connecting rods, pistons and pins are of heavy construction due to the high compression ratio required to ignite the diesel fuel. The diesel fuel is ignited when the heat developed in the combustion chamber during the compression stroke reaches a certain temperature.
The valve train operates the same as in the gasoline engine, but are of special design and material for diesel operation. The stainless steel pre-chamber inserts in the cylinder head combustion chambers are serviced separately from the cylinder head. With the cylinder head removed, these pre-chamber inserts can be driven from the cylinder head after removing the glow plugs or injection nozzles. The glow plugs are threaded into the cylinder head and the injection nozzles are retained by a bolt and clamp. The injection nozzles are spring loaded and calibrated to open at a specified fuel pressure.