1.6 Piston and Piston Rings
DETROIT DIESEL 53
The compression rings may be inspected through the ports in the cylinder liners after the air box covers have been
removed. If the rings are free and are not worn to the extent that the plating or grooves are gone, compression should be
within operating specifications. Refer to Section 15.2 for the procedure for checking compression pressure.
Remove Piston and Connecting Rod
1. Drain the cooling system.
2. Drain the oil and remove the oil pan.
3. Remove the oil pump and inlet and outlet pipes, if necessary (Section 4.1).
4. Remove the cylinder head (Section 1.2).
5. Remove the carbon deposits from the upper inner surface of the cylinder liner.
6. se a ridge cutter to remove any ridge in the cylinder liner at the top of the piston ring travel.
NOTE: Move the piston to the bottom of its travel and place a cloth over the
top of the piston to collect the cuttings. After the ridge has been removed, turn
the crankshaft to bring the piston to the top of its stroke and carefully remove
the cloth with the cuttings.
7. Remove the bearing cap and the lower bearing shell from the connecting rod. Then push the piston and rod
assembly out through the top of the cylinder block. The piston cannot be removed from the bottom of the cylinder block.
Fig. 3 - Cleaning Piston
8. Reassemble the bearing cap and lower bearing shell to the connecting rod.
Disassemble Piston and Connecting Rod Note the condition of the piston and rings. Then remove the rings and
connecting rod from the piston as follows:
1. Secure the connecting rod in a vise equipped with soft jaws and remove the piston rings with tool J 8128 as shown in
Fig. 2.
2. Punch a hole through the center of one of the piston pin retainers with a narrow chisel or punch and pry the retainer
from the piston, being careful not to damage the piston or bushings.
3. Withdraw the piston pin from the piston, then remove the connecting rod.
4. Drive the remaining piston pin retainer out from the inside with a brass rod or other suitable tool.
Clean Piston Clean the piston components with fuel oil and dry them with compressed air. If fuel oil does not remove
the carbon deposits, use a chemical solvent (Fig. 3) that will not harm the piston pin bushings or the tin- plate on the
piston.
The upper part of the piston, including the compression ring lands and grooves, is not tin-plated and may be wire-brushed
to remove any hard carbon. However, use care to avoid damage to the tin-plating on the piston skirt. Clean the ring
grooves with a suitable tool or a piece of an old compression ring that has been ground to a bevel edge.
Clean the inside surfaces of the piston and the oil drain holes in the piston skirt. Exercise care to avoid enlarging the
holes while cleaning them.
Inspection
If the tin-plate on the piston and the original grooves in the piston rings are intact, it is an indication of very little wear.
Excessively worn or scored pistons, rings or cylinder liners may be an indication of abnormal maintenance or operating
conditions which should be corrected to avoid recurrence of the failure. The use of the correct types and proper
maintenance of the lubricating oil filters and air cleaners will reduce to a minimum the amount of abrasive dust and
foreign material
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