The cylinder head gasket is mounted between the cylinder block and the cylinder head. It prevents combustion gasses, coolant and oil from leaking out between the cylinder block and the cylinder head. This requires resisting pressure, heat resistance and proper elasticity. The steel laminate type cylinder head gasket is used in order to improve the durability of the cylinder head gasket so that combustion gas leakage is prevented. The thickness of the cylinder head gasket is selected to improve compression ratio precision according to the engine. The thickness of the cylinder head gasket is determined by the amount of protrusion of the piston. Example3L engine

The 3L engine has three types of cylinder head gaskets.

Mark B1.4- 1.5mm (0.0551 – 0.0591 in.)

Mark D1.5- 1.6mm (0.0591 – 0.063in.)

Mark F1.6- 1.7mm (0.063- 0.066in.)

EngineCrankshaft

The crankshaft acts to convert the linear motion of the pistons into revolving motion. In order to be able to receive great force and revolve at high speed, it needs enough strength and rigidity, along with durability to wear, and to be statically and dynamically balanced to rotate smoothly. The crank pin and the crank journal are attached by a hardening process in order to make it enduring and durable against wear. The balance weight is installed to balance with the crankshaft rotation. The crank pin and the crank journal have an oil hole. The oil travels from the cylinder block, enters into the oil hole of the journal and goes through to the crank pin.

REFERENCE

Crankshaft Offset

Offsetting the crankshaft center and the cylinder bore center serves to raise engine efficiency

The maximum amount of combustion pressure that the pistons receive can be efficiently transferred to thecrankshaft.

By reducing the amount of force in the thrust direction of the piston, friction loss is reduced.

HINT:

ExampleAmount of crankshaft offset

1NZ-FE and 2NZ-FE engines12 mm (0.472 in.)

1SZ-FE and 2SZ-FE engines8 mm (0.315 in.)

The numbers for the journal installation

position and installation orientation are

inscribed on the crankshaft bearing cap.

ExampleZZ engine series.

Some bearing caps are single unit with

ladder-frame construction, which consists

of the bottom of the cylinder block.