1.2 Cylinder Head
DETROIT DIESEL 53
warpage, under ordinary conditions, reduces valve
Cylinder Head Maintenance
reconditioning to a minimum.
Engine temperatures should be maintained between
160o and 185°F. and the cooling system should be
To ensure efficient cooling, each fuel injector is
inserted into a thin-walled tube which passes through
inspected daily and kept full at all times.
the water space in the cylinder head. The lower end of
Unsuitable water in the cooling system may result in
the injector tube is pressed into the cylinder head and
lime and scale formation which prevent proper
flared over; the upper end is flanged and sealed with a
cooling. The cylinder head should be inspected around
neoprene seal. The flared lower end and sealed upper
the exhaust valve water jackets. This can be done by
end prevent water leaks around the copper tube.
removing an injector tube. Where inspection discloses
The exhaust passages from the exhaust valves of each
such deposits, a reliable non-corrosive scale remover
cylinder lead through a single port to the exhaust
should be used to remove the deposits from the
manifold. The exhaust passages, exhaust valve inserts
cooling system of the engine, since a similar condition
and injector tubes are completely surrounded by
will exist in the cylinder block and other components
cooling system water.
of the engine. Refer to Section 13.3 for engine coolant
In addition to being surrounded by water, cooling of
Adding cold water to a hot engine may result in head
these areas is further assured by the use of double jet
cracks. Water must be added slowly to a hot engine to
spray nozzles installed between each pair of cylinders
avoid rapid cooling which will result in distortion and
in the water inlet ports of four valve cylinder heads.
cracking of the cylinder head (and cylinder block).
Nozzle holes are so positioned in the cylinder head
that the comparatively cool water which enters the
Loose or improperly seated injector (tubes may result
head is directed at high velocity against the sections of
in compression leaks into the cooling system and cause
the head which are subjected to the greatest heat.
a loss of engine coolant. The tubes should be tight and
properly seated. Refer to Section 2.1.4.
The development of cracks in the cylinder head may
be caused by abnormal operating conditions or
through neglect of certain maintenance items. If this
To seal compression between the cylinder head and
type of failure should occur, a careful inspection
the cylinder liner, separate laminated metal gaskets
should be made to determine the cause so that a
are provided at each cylinder. Water and oil passages
recurrence of the failure will be prevented.
between the block and head are sealed with synthetic
Overtightening the injector clamp bolts may also result
the block. A synthetic rubber seal fits into a milled
in head cracks. Always use a torque wrench to tighten
groove in the block near the outer edge of the area
the bolts to the specified torque.
covered by the cylinder head. When the cylinder head
is pulled down, a positive leakproof metal-to-metal
Other conditions which may eventually result in head
contact is assured between the head and block.
Certain service operations on the engine require the
1. Excess fuel in the cylinders due to leaking injectors.
removal of the cylinder head. These operations are:
2. Oil pull-over due to an overfilled air cleaner sump,
or improper viscosity oil in the air cleaner.
1. Removing and installing the pistons.
3. Neglected cylinder block air box drains which allow
2. Removing and installing the cylinder liners.
accumulated oil to be drawn into the cylinders.
3. Removing and installing the exhaust valves.
Remove Cylinder Head
4. Removing and installing the valve guides.
Due to various optional and accessory equipment used
5. Reconditioning the exhaust valves and valve seats.
on the different engine models, only the general steps
for removal of the cylinder head are covered. If the
6. Replacing the injector tubes.
engine is quipped with special accessories that affect
7. Installing new cylinder head gaskets.
cylinder head removal, note the position of each
before disconnecting or removing them to assure the
8. Removing and installing a camshaft.