TM 5-3810-300-24&P-3
1.7.2
CAMSHAFT, BALANCE SHAFT AND BEARINGS
The camshaft and the balance shaft are located near the
piece bearings support the camshaft at uniform intervals
top of the cylinder block (Fig. 1) and each may be
throughout its length. The intermediate bearings are
located on either side of the engine, depending upon the
secured to the camshaft by lock rings, thereby permitting
engine model. The camshaft actuates the valve and
them to be inserted into the cylinder block with the
injector operating mechanism.
shafts. Each intermediate bearing is secured in place,
after the camshafts are installed, with a lock screw
The accurately ground cams on the camshaft ensure
threaded into a counterbored hole in the top of the
efficient, quiet, cam follower roller action, and are heat
cylinder block.
treated to provide a hard wear surface.
On both the camshaft and the balance shafts the gear
The current engines are equipped with a low velocity, low
thrust load is absorbed by two thrust washers, one on
lift injector cam lobe and a long closing ramp exhaust
each end of the rear bearings of the "A" and "'D" basic
cam lobe design camshaft.
Former engines were
engines and at the front end of the "B" and "C" engines.
equipped with a high lift injector cam lobe camshaft. The
The thrust washers bear against thrust shoulders on the
two camshafts are interchange-able and only the current
shafts.
camshaft, which can be identified by the numeral "7"
stamped on one end of the camshaft, is serviced.
A helical drive gear with a counterweight is secured to
each shaft with a Woodruff key, nut, nut retainer, retainer
Both ends of the cam and balance shaft are supported
bolts and lock washers. The
by bearing assemblies, each consisting of a flanged
housing and two bushings. In addition, intermediate two-
1.
Camshaft
14.
Bearing--Camshaft--
26.
Bearing--Balance
32.
Bearing--Balance
2.
Cam
Intermediate
Shaft--Front
Shaft--Rear
3.
Bearing--Camshaft Thrust
17.
Bearing--Camshaft--Rear
27.
Washer--Balance
33.
Gear--Balance
6.
Washer--Camshaft Thrust
18.
Gear--Camshaft--
Shaft Thrust
Shaft--R.H Helix
12.
Thrust Shoulder--
L.H. Helix
31.
Thrust Shoulder--
40.
Balance Weight
Camshaft
25.
Balance Shaft
Balance Shaft
41.
Hub--Balance Weight
Fig. 1 - Camshaft and Balance Shaft Assemblies
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