Frequency and voltage regulation, stability,
andtransient response test, short term. Refer to
b. Frequency adjustment range test. Refer to
a. The turbocharger is an exhaust driven blower
used to boost the power output of an engine over that
of a naturally aspirated engine by increasing the sup-
ply of air to the cylinders. The turbocharger incor-
porates a single stage radial inflow turbine wheel,
mounted on a common shaft with a single stage cen-
trifugal compressor impeller. It has a one-piece
center housing with floating sleever type bearings,
a turbine housing, and a compressor housing.
b. The turbocharger responds to engine load
demands by reacting to the flow of expanding exhuast
gases and supplying a correlated volume of air to the
During a heavy load/lugging
operation, the increased flow of exhaust gases turns
the turbine wheel faster, causing the compressor
impeller to turn faster to supply more air to the in-
take manifold, Conversely, when engine load is light
and the radial flow of gases within the turbine de-
creases, the turbocharger compressor reduces the
supply of air to the intake manifold.
c. The turbocharger bearings are lubricated and
cooled by filtered engine oil circulating through the
center housing under normal oil pump pressure. This
oil is supplied to the center housing through an ex-
ternal line through the engine main oil filter. Oil
returns to the crankcase through an external line
which extends from the bearing housing to the side of
the cylinder block.
d. The turbine of the turbocharger is part of the
The exhaust manifold on a turbo-
charged engine is in three sections with the front and
the rear sections inserted into the center section.
The manifold is sealed to the exhaust parts of the
cylinder head with a steel gasket and secured in
place with capscrews and lock washers.
14-52. Turbocharger Removal and Disassembly.
While turbocharger is off engine, keep
all manifold openings covered to prevent
entry of foreign objects.
a. Refer to Operator arid Organizational Mainte-
nance Manual for symptoms and isolation of malfunc-
tion of the turbocharger.
b. Refer to Operator and Organizational Mainte-
nance Manual and remove turbocharger,
c. Disassemble turbocharger in the numerical
sequence illustrated in figure 14-26.
Do not rest the center housing with the
included stationary and rotating parts on
the compressor impeller. Weight of the
complete assembly will damage the im-
d. Mark the relative positions of the compressor
and-turbine housings to the center housing to facilitate
e. Apply penetrating oil, or diesel fuel, to the
bolts that secure the turbine housing and backplate
to the center housing.
f. Remove the compressor housing. If necessary,
tap the housing lightly with a soft hammer to loosen
it. Remove the diffuser (3).
g. Record the shaft radial movement and shaft
(1) Check shaft end play as follows: (Specified
end play .001 to .0042.
(a) Clamp the turbine housing flange in a
(b) Use either a clamp or magnetic base dial
(c) Place indicator contact point on end of
(d) Press up on turbine wheel to force the
impeller to extreme up position; record indicator
(e) Press down on impeller; again record
(f) The difference between the readings is
the end play,
(g) End play should be from .001 to .0042.
(h) Record the end play, This will be used
to determine if thrust plate assembly or thrust bear-
ing need to be replaced.
(i) If end play exceeds .0042, it indicates