TM 5-3895-346-14
CYLINDER BLOCK
ENGINE OVERHAUL
METHOD B
This method may be used when a large water tank is unavailable, or when it is desired to check the block for
cracks without removing the engine from the equipment which it powers. However, it is necessary to remove
the cylinder head(s), blower, oil cooler, air box covers, and oil pan.
1.
Prepare the block as outlined in Method A. However, before installing the large sealing plate, fill
the water jacket with a mixture of water and one gallon of permanent-type antifreeze. The antifreeze will
penetrate small cracks and its color will aid in detecting their presence.
2.
Install the plate(s) and water hole covers as outlined in Method A.
3.
Apply 40 psi (276 kPa) air pressure to the water jacket and maintain this pressure for at least two
hours to give the water and antifreeze mixture ample time to work its way through any cracks which may exist.
4.
At the end of this test period, examine the cylinder bores, air box, oil passages, crankcase, and
exterior of the block for presence of the water and antifreeze mixture, which will indicate the presence of
cracks. A cracked cylinder block must be replaced by a new block.
5.
After the pressure test is completed, remove the plates and drain the water jacket. Then remove
the liners and seal rings and blow out all the passages in the block with compressed air.
6.
Dry the cylinder liners with compressed air and coat them with oil to prevent rust.
Inspect Cylinder Block
After cleaning and pressure testing, inspect the
cylinder block.
1.
Check the block bores as follows:
a.
Make sure the seal ring grooves
(Fig. 8) are thoroughly clean. Then inspect the
grooves and lands for evidence of pitting and erosion.
Two grooves are provided above the air inlet ports of
each cylinder bore in the current block. The single
groove formerly below the air inlet ports has been
eliminated. However, a cylinder liner seal ring is
required in the upper groove only. The lower groove
(on the current block) is provided for the seal ring if
inspection reveals extensive pitting or erosion along
the upper land or inner surface of the upper groove. If
both grooves are eroded to the extent that sealing is
affected, then the block must be replaced.
b.
Measure the entire bore of each
cylinder with cylinder bore gage J 5347-01 (Fig. 9)
which has a dial indicator calibrated in 0.0001 inch
increments. Use dial bore gage setting tool Figure 8.
Figure 8. Location of Block Bore Seal Ring
Location of Block Bore Seal Ring Groove
Groove
62
