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
To ensure efficient cooling, each fuel injector is inserted
160 and 185F. and the cooling system should be
into a thin-walled tube which passes through the water
inspected daily and kept full at all times.
space in the cylinder head. The lower end of the
injector tube is pressed into the cylinder head and flared
Unsuitable water in the cooling system may result in
over; the upper end is flanged and sealed with a
lime and scale formation which prevent proper cooling.
neoprene seal. The flared lower end and sealed upper
The cylinder head should be inspected around the
end prevent water leaks around the copper tube.
exhaust valve water jackets. This can be done by
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 cooling
manifold. The exhaust passages, exhaust valve inserts
system of the engine, since a similar condition will exist
and injector tubes are completely surrounded by cooling
in the cylinder block and other components of the
system water.
engine. Refer to Section 13.3 for engine coolant
recommendations.
In addition to being surrounded by water, cooling of
these areas is further assured by the use of double jet
Adding cold water to a hot engine may result in head
spray nozzles installed between each pair of cylinders in
cracks. Water must be added slowly to a hot engine to
the water inlet ports of four valve cylinder heads.
avoid rapid cooling which will result in distortion and
Nozzle holes are so positioned in the cylinder head that
cracking of the cylinder head (and cylinder block).
the comparatively cool water which enters the head is
directed at high velocity against the sections of the head
Loose or improperly seated injector tubes may result in
which are subjected to the greatest heat.
compression leaks into the cooling system and cause a
loss of engine coolant. The tubes should be tight and
properly seated. Refer to Section 2.1.4.
To seal compression between the cylinder head and the
cylinder liner, separate laminated metal gaskets are
The development of cracks in the cylinder head may be
provided at each cylinder. Water and oil passages
caused by abnormal operating conditions or through
between the block and head are sealed with synthetic
neglect of certain maintenance items. If this type of
rubber seal rings which fit into counterbored holes in the
failure should occur, a careful inspection should be
block. A synthetic rubber seal fits into a milled groove
made to determine the cause so that a recurrence of the
in the block near the outer edge of the area covered by
failure will be prevented.
the cylinder head. When the cylinder head is pulled
down, a positive leakproof metal-to-metal contact is
Overtightening the injector clamp bolts may also result
assured between the head and block.
in head cracks. Always use a torque wrench to tighten
the bolts to the specified torque.
Certain service operations on the engine require the
removal of the cylinder head. These operations are:
Other conditions which may eventually result in head
cracks are:
1.
Removing and installing the pistons.
1. Excess fuel in the cylinders due to leaking injectors.
2.
Removing and installing the cylinder liners.
2. Oil pullover due to an overfilled air cleaner sump, or
3.
Removing and installing the exhaust valves.
improper viscosity oil in the air cleaner.
4.
Removing and installing the valve guides.
3. Neglected cylinder block air box drains which allow
5.
Reconditioning the exhaust valves and valve seats.
accumulated oil to be drawn into the cylinders.
6.
Replacing the injector tubes.
7.
Installing new cylinder head gaskets.
Remove Cylinder Head
8.
Removing and installing a camshaft.
Only the general steps for removal of the cylinder head
are covered. If the engine is equipped with special
accessories that affect cylinder head removal, note the
position of each before disconnecting or removing them
to assure the correct reinstallation.
1970 General Motors Corp.
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