E N G I N E
A I R I N L E T A N D E X H A U S T S Y S T EM
S Y S T E M S O P E R A T I O N
charger turbine wheel and compressor wheel to
turn faster. The increased rpm of the compressor
wheel increases the quantity of inlet air. As the
turbocharger provides additional inlet air, more
fuel can be burned. This results in more horse-
power from the engine.
1. Air inlet. 2. Compressor wheel. 3. Oil inlet passage,
4. Turbine wheel. 5. Exhaust outlet. 6. Oil outlet. 7.
Maximum rpm of the turbocharger is controlled
by the rack setting, the high idle speed setting and the
height above sea level at which the engine is
If the high idle rpm or the rack setting is higher
than given in the FUEL SETTING INFORMA-
TION (for the height above sea level at which
the engine is operated), there can be damage
to engine or turbocharger parts.
The bearings for the turbocharger use engine
oil for lubrication. The oil comes in through oil
inlet (3) and goes through passages in the center
section for lubrication of the bearings. Oil from
the turbocharger goes out through oil outlet (6)
in the bottom of the center section and goes back
to the engine oil pan.
CYLINDER HEAD AND VALVES
There is one cylinder head for all four cylinders.
Each cylinder has one intake and one exhaust valve.
Each intake and exhaust valve has a valve rotator.
The valve rotator causes the valve to turn a small
amount each time the valve opens and closes. This
action helps keep carbon deposits off of the valve face
and valve seat.
The cylinder head has valve seats installed and
they can be replaced.
The valve guides can be replaced. There are
threads on the inside diameter of the valve guides to
hold oil that lubricates the valve stem.
The valve mechanism controls the flow of intake
air and exhaust gases in and out of the cylinders. The
valve mechanism consists of rocker arms, push rods,
valve lifters and camshaft.
The camshaft is driven by and timed to the crank-
shaft. When the camshaft turns, the camshaft lobes
move the valve lifters up and down. The valve lifters
move the push rods which move the rocker arms.
Movement of the rocker arms make the intake and
exhaust valves open according to the firing order
(injection sequence) of the engine. A valve spring for
each valve makes the valve go back to the closed
position and holds it there.