TM 5-3810-300-24 & P3
Cylinder Block
1.1
g. Wash the block in clean water or steam clean it.
4. Dry the cylinder block with compressed air.
5. Make certain that all water passages, oil galleries and air
box drain holes have been thoroughly cleaned.
NOTE: The above cleaning procedure may
be used on all ordinary cast iron and steel
parts of the engine. Mention will be made of
special cleaning procedures whenever
necessary.
After the cylinder block has been thoroughly cleaned and
dried, reinstall the core hole plugs. Coat the threads of the
plugs with sealant. Install the core hole plugs in the sides of
the block from 2" to 2-1/4" below the machined surface of the
block. They must be water tight. The core hole plugs in the
ends of the block are flanged to provide a positive stop against
the counterbore of the hole, thus preventing the plugs from
entering the water jacket and restricting the flow of water. Soft
aluminum gaskets are used with the plugs. Coat the threads
of the end plugs with sealant and, using new gaskets, reinstall
the plugs and tighten them to 150-180 lb-ft (204-244 Nm)
CAUTION: Excessive torque applied to the
core hole plugs may result in cracks in the
water jacket.
Fig. 10 Honing Bore of Cylinder Block
Pressure Test Cylinder Block
tank is available and the cylinder block is completely stripped
Extremely tight fitting cylinder liners, severe scoring of the
of all parts.
liners and overheating of the engine may result in cracks in the
cylinder bores. Overheating of the engine may also result in
I. Immerse the block for twenty minutes in a tank of water
cracks between the water jackets and the oil passages.
heated to 180-200 F (82-93 C).
The cylinder block may be pressure tested for cracks or leaks
2. Apply 40 psi (276 kPa) air pressure to the water jacket and
by either one of two methods. In either method, it will be
observe the water in the tank for bubbles which indicate the
necessary to make plates (Fig. 8) to seal the water openings
presence of cracks or leaks in the block. A cracked cylinder
in the top of the block. Main bearing caps may be used to
block must be replaced by a new block.
secure the plates to the block with the cylinder head bolts and
nuts. Cylinder head seal rings may be used as gaskets
3. After the pressure test is completed, remove the block from
between the plates and the block. It will also be necessary to
the water tank. Then remove the plates and gaskets and dry
use water hole cover plates and gaskets to cover the water
the block with compressed air.
pump inlet openings in the block. Drill and tap one cover plate
to provide a connection for an air line (Fig. 9).
METHOD "B"
With the cylinder block prepared in the above manner, the
This method may be used when a large water tank is
core hole plugs installed and the plugs removed from the oil
unavailable, or when it is desired to check the block, for cracks
passages, test the block as follows:
without removing the engine from the vehicle. However, it is
necessary to remove the cylinder head, blower, oil cooler, air
METHOD "A"
box covers and oil pan.
This method may be used when a large enough water
1. Attach sealing plates and gaskets as in Method "A".
However, before attaching the last sealing plate, fill the water
jacket with a mixture of water and one
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