DETROIT DIESEL 53
1.3.4
CRANKSHAFT MAIN BEARINGS
The crankshaft main bearing shells (Figs. 1 and 2) are precision made and are replaceable without machining. They
consist of an upper bearing shell seated in each cylinder block main bearing support and a lower bearing shell seated in
each main bearing cap. The bearing shells are prevented from endwise or radial movement by a tang at the parting line
at one end of each bearing shell. The tangs on the lower bearing shells are off-center and the tangs on the upper bearing
shells are centered to aid correct installation.
On In-line engines, a 7/16" oil hole in the groove of each upper bearing shell, midway between the parting lines, registers
with a vertical oil passage in the cylinder block. Lubricating oil, under pressure, passes from the cylinder block oil gallery
by way of the bearing shells to the drilled passages in the crankshaft, then to the connecting rods and connecting rod
Fig. 1 - Main Bearing Shells, Bearing Caps and Crankshaft Thrust Washers -- In-Line Engines
April, 1974
SEC. 1.3.4
Page 1
