1948-1952 Shop Service Manual - - Hudson-Essex-Terraplane Club

2 - 2 ENGINE TUNE-UP
ENGINE TUNE-UP
Modern high compression, high speed engines require
periodic diagnosis and adjustments to maintain peak performance
and economical operation. A periodic engine tuneup
will assure this maximum engine performance, fuel
economy and dependability.
Accurate testing equipment in good condition is essential
to proper diagnosis. If a master tester is used, the battery of
the tester should be maintained in a fully charged condition.
The tune-up procedure is arranged in the usual order of
performance. Only by performing the operations in the
following procedure and adhering to the limits and specifications
given therein is it possible to obtain the maximum
performance and economy built into Hudson engines.
BATTERY
Many of the tests involved in tune-up are dependent upon
a battery in good condition. If the battery is below standard,
it should be recharged, or replaced with a fully charged
battery before the tune-up.
BATTERY SPECIFIC GRAVITY:
Check the battery specific gravity with a hydrometer,
Figure 1. A battery when fully charged should show 1.270
specific gravity at 70° F. A uniform hydrometer reading
below 1.225 at 70° F. indicates a low battery that should be
recharged.
If gravity varies more than 25 points between cells, battery
should be recharged and tested under load.
CAUTION: Electric storage batteries give off highly inflammable
hydrogen gas when being charged and continue
to do so for some time after receiving a steady
charge. Do Not allow sparks or an open f la m e near the
battery, especially in the vicinity of the battery vent caps.
Before doing any work around the battery, a metallic
contact between the car bumper and the ground should be
made to remove any possibility of a static charge causing
a spark in the vicinity of the battery.
BATTERY LOAD TEST:
Battery may be tested under load by connecting a voltmeter
across the battery terminals and cranking the engine.
Battery is satisfactory if it will crank the engine at a good
speed for 1/2 minute and the voltage does not fall below
4-1/2 volts. Slow cranking speed or lower voltage may be
due to high resistance in the starter circuit. Check cables and
retest. (DO NOT CRANK MORE THAN 1/2 MINUTE
AT A TIME ).
A standard cell tester may be used to make the load test.
The cell tester has a shunt across the terminals which places
each cell, under load. Each cell should show 1-1/2 volts or
over, and the variation between cells should not exceed .15
volts.
FIGURE 1
FIGURE 2