DETROIT DIESEL 53
Piston and Piston Rings 1.6
Fig 4 - Comparison of Pistons
introduced into the cylinders 'and will reduce the rate of wear.
Long periods of operation at idle speed and the use of improper lubricating oil or fuel must be avoided, otherwise a heavy
formation of carbon may result and cause the rings to stick.
Keep the lubricating oil and engine coolant at the proper levels to prevent overheating of the engine.
Examine the piston for score marks, cracks, damaged ring groove lands or indications of overheating. A piston with light
score marks which may be cleaned up may be 're-used (Fig. 4). Any piston that has been severely scored or overheated
must be replaced. Indications of overheating or burned spots on the piston may be the result of an obstruction in the
connecting rod oil passage.
Replace the piston if cracks are found across the internal struts. Use the magnetic particle inspection methods outlined
in Section 1.3 under Crankshaft Inspection for locating cracks in the piston.
Check the cylinder liner and block bore for excessive out-of-round, taper or high spots which could cause failure of the
piston (refer to Section 1.0 for specifications).
Inspection of the connecting rod and piston pin are covered in Section 1.6.1.
Other factors that may contribute to piston failure include oil leakage into the air box, oil pull-over from the air cleaner,
dribbling injectors, combustion blow- by and low oil pressure (dilution of the lubricating oil).
Inspect and measure the piston pin bushings. The piston pin-to-bushing clearance with new parts is .0025" to .0034". A
maximum clearance of .010" is allowable with' worn parts. The piston pin bushings in the connecting rod are covered in
Remove Bushings from Piston
1. Place the piston in the holding fixture J 1513-1 so that the bushing bores are in alignment with the hole in the fixture
base.
2. Drive each bushing from the piston with the bushing remover J 4972-4 and handle J 1513-2 (Fig. 5).
Install Bushings in Piston
1. Place the spacer J 7587-f in the counterbore in the fixture J 1513-1 (small end up).
April, 1974
SEC. 1.6 Page 3
