DETROIT DIESEL 53
Each connecting rod (Figs. 1 and 2) is made of steel
forged to an "I" section with a closed hub at the upper
end and a cap at the lower end. The rod is drilled to
provide lubrication to the piston pin at the upper end and
is equipped with an oil spray nozzle for cooling the
underside of the piston head,
A helically-grooved bushing is pressed into each side of
the connecting rod at the upper end. A cavity of
approximately 1/8" between the inner ends of these
bushings, registering with the drilled oil passage in the
connecting rod, forms a duct around the piston pin. A
portion of the oil from this duct lubricates the piston pin
and bushings, the remainder of the oil is forced out of
the spray nozzle. The piston pin floats in both the piston
and connecting rod bushings.
Service connecting rod assemblies include the lower
bearing cap, bolts, nuts, spray nozzle and the upper
piston pin bushings pressed in place and bored to size.
Fig. - 2..-Typical Connecting Rod Details and Relative
Location of Parts
Disassemble Connecting Rod from Piston (Rod and
Piston Assembly Removed from Engine)
Fig. 1. Connecting Rod Mounting
Disassemble the piston and connecting rod as outlined
in Section 1.6.
Inspect Connecting Rod and Piston Pin
Clean the connecting rod and piston pin with fuel oil and
dry them with compressed air.
Blow dry compressed air through the oil passage in the
connecting rod and the spray nozzle to be sure the holes
1970 General Motors Corp.
SEC. 1.6.1 Page 1