This document is printed from SPI². Not for RESALE
Lip type seals are used on both the front of the
crankshaft and the rear of the crankshaft.
A timing ring is installed to the crankshaft. The timing
ring is used by the ECM in order to measure the
engine speed and the engine position.
A timing ring for the balancer can be installed to the
crankshaft. The timing ring for the balancer drives the
balancer.
Gears and Timing Gear Case
Illustration 7 g02859276
Typical example
The crankshaft oil seal is mounted in the cover of the
timing case. The timing case is made of cast iron. The
timing case cover is made from aluminum.
The timing gears are made of steel.
The crankshaft gear (5) drives the camshaft gear (4)
and an idler gear (6) for the engine oil pump. The idler
gear (6) for the engine oil pump drives the oil pump
gear (7). The camshaft gear (4) drives the idler gear
(2) and the accessory drive gear (3). The idler gear
(2) drives the fuel injection pump gear (1).
The camshaft gear rotates at half the engine speed.
The fuel injection pump gear rotates at one and a half
times engine speed.
Camshaft
The engine has a single camshaft. The camshaft is
made of cast iron. The camshaft lobes are chill
hardened.
The camshaft is driven at the front end. As the
camshaft turns, the camshaft lobes move the valve
system components. The valve system components
move the cylinder valves.
The camshaft gear must be timed to the crankshaft
gear. The relationship between the lobes and the
camshaft gear causes the valves in each cylinder to
open at the correct time. The relationship between
the lobes and the camshaft gear also causes the
valves in each cylinder to close at the correct time.
UENR0623 9
Engine Operation