DETROIT DIESEL 53
1.7.2
CAMSHAFT, BALANCE SHAFT AND BEARINGS
The camshaft and balance shaft used in the In-line engines, are located just below the top of the cylinder block.
The camshaft and balance shaft in the In-line engines may be positioned on either side of the engine as
required by the engine rotation and accessory arrangement.
The shafts are supported by bearings (bushing type) that are pressed into bores in the cylinder block. The
balance shaft is supported by front and rear bearings only, whereas the camshaft is supported by end,
intermediate and center bearings. The camshafts in the three cylinder engine are supported by two end
bearings and two intermediate bearings.
To facilitate assembly, letters signifying the engine models in which a shaft may be used are stamped on the
ends of the shaft. The letters on the timing gear end of the camshaft must correspond with the engine model.
For example, the letters RC are stamped on a camshaft used in an RC model engine. For additional
identification, a camshaft with no designation on the ends or a "7" stamped on the ends is a high-velocity high-
lift camshaft. A camshaft stamped with a "V" or "V7" is a low velocity high-lift camshaft.
Figure 1. Removing or Installing Nut on Camshaft or Balance Shaft
NOTE: The low lift camshaft which provides a maximum valve cam lobe
lift of .276" is stamped "V7L" on both ends.
Lubrication is supplied under pressure to the camshaft and balance shaft end bearings via oil passages
branching off from the main oil gallery direct to the camshaft end bearings.
In addition, oil is forced through an oil passage in each camshaft which lubricates the camshaft intermediate
bearings. On the current camshafts, the intermediate journal oil grooves were eliminated and a chamfer added
to the intermediate journal oil holes. When replacing a former camshaft with a current camshaft, always use
new bearings.
All of the camshaft and balance shaft bearings incorporate small slots through which lubricating oil is directed
to the cam follower rollers.
Remove Camshaft or Balance Shaft
Whenever an engine is being completely reconditioned or the bearings, thrust washers, or the gears need
Fig . 2. Removing or Installing Thrust Washer Retaining Bolts
August, 1972 SEC. 1.7.2 Page 1
