The engine is a four-cycle, six cylinder over-head valve type, with force feed lubrication, and water cooled. This engine has a displacement of 3.878 liters (236.7 cu. in), with 90 mm (3.54") bore, and 101.6 mm (4.00") stroke. The compression ratio is 7.8 to 1.
The cylinder head being made of integral casting with wedge shaped type combustion chambers provides efficient heat distribution.
Also together with the independent inlet and outlet ports provide smooth performances during slow, intermediate, and high speed operations.
The cylinder block and crankcase assembly is the major section of the engine, and is cast integrally, forming a rigidly reinforced unit, and is integrally cast with coolant passages in the block for cooling the entire length of the cylinder.
Tiie engine is equipped with a fully counterbalanced crankshaft which contributes smooth engine performances. The crankshaft is supported by four bearings, which are of steel backed aluminum alloy linings and replaceable insert type. The crankshaft end play is controlled by the third crankshaft journal and the bearings. The crankshaft bearing caps are large in size to assure rigid support of the bearings and the crankshaft.
The pistons are of special light alloy with eccentric finished slightly larger at the right angle to the piston pin. Two compression rings and two oil rings are used on each piston.
Fig. 1-2 Cross Section G1566 Front View
The connecting rods are "I" beam section forged steel. The upper end is fitted with a clamp bolt to secure the connecting rod onto the piston pin. Connecting rod bearings are interchangeable insert type, and are of steel backed aluminum alloy linings.
The camshaft is of cast iron with cam lobe surfaces chill treated, and is supported with four bearings. The camshaft bearings of steel backed babbitt lined construction provide a uniform expansion and durability. The bearings are installed in the cylinder block and for perfect alignment.
A heavy cast iron flywheel is bolted onto the flange at the 4 rear end of the crankshaft, and ring gear is shrunk fit onto the outer diameter of the flywheel , and the starter clutch pinion gear engages this ring gear when cranking the engine. The flywheel and the crankshaft are accurately balanced to prevent engine vibration, and the flywheel surface is accurately machined for clutch operation.
The distributor is mounted on the right side of the cylinder block, and is gear driven by the camshaft. The distributor is provided with the centrifugal advancer and the vacuum advancer mechanism to insure efficient performances under various operations.
The carburetor is of 2-barrel type, which ensures appropriate supply of air-fuel mixture as per demands of the engine under various operating conditions, the 2-barrel type is used both in Land Cruiser and trucks commencing from the Engine No. F-294920.
The fuel pump is a diaphragm type, and is operated by the camshaft cam.
The lubrication system is an all forced-feed, partial flow filtering type. The oil pump is a gear type and is driven by the camshaft through the distributor shaft.
The cooling system is a pressure forced circulation type, and the water pump is a six blade impeller centrifugal type, which is driven by the crankshaft pulley through the "V" belt. The radiator is fin and tube type, and the pressure is sustained by the radiator cap. Circulation of the coolant is controlled by the wax pellet element type thermostat.
The charging system is composed of the alternator, and the regulator. The alternator is driven by the crankshaft pulley through the "V" belt. This alternator provides an efficient output at lower engine speeds, and a very high output at cruising speed.
The starter is incorporated with the magnetic switch and the starter clutch. The magnetic switch and the starter clutch enable to accomplish a smooth meshing, and the starter clutch prevents the over-running of the armature.
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