ROBERT BOSCH MODEL MW INJECTION PUMP
MULTIPLE PLUNGER DESIGN
The injection pump is of the multiple plunger design with
one plunger, barrel and delivery valve assembly for each
engine cylinder (Figure 3). Each plunger is activated by
the pump camshaft through roller tappet followers. Pump
rotation, as viewed from the drive end of the pump, is
clockwise and at one-half engine speed. Three gears
are used to drive the injection pump; the crankshaft gear,
engine idler gear and the injection pump gear which is
bolted to the injection pump hub.
INJECTION PUMP LUBRICATION
Engine lubricating oil flows through an external line from
the crankcase to a pump housing oil inlet fitting located
slightly to the rear of the hand priming pump (Figure 4).
Oil then flows through a housing passage which indexes
with the number four tapped body. All oil lubricated parts
within the injection pump and governor are lubricated by
splash with the exception of the number four tappet
body. Oil flow into the injection pump is very low.
Therefore, a minimum of one pint of oil must be added
through the upper governor housing plug when an
injection pump is installed. Return oil flows out of the
injection pump housing at an opening just above the
front camshaft bearing and into the engine front cover.
Engine oil and filters should be changed at the intervals
recommended by International Harvester to prevent
buildup of wear materials in the oil, replace essential
disparancy. If inadequate oil filters, extended oil drain
intervals, or non-recommended oil classifications are
used, engine and injection pump life will be reduced.
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