Compression Pressure Measurement; Inspection; Measurement - Mitsubishi S3L Service Manual

OVERHAUL INSTRUCTIONS
t
Figure 3 Compression gauge and adaptor
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Figure 4 Measuring compression pressure
CAUTION
• It is important to measure the compression
pressure at regular intervals to obtain the data on
the gradual change of the compression pressure.
• The compression pressure would be slightly
higher than the standard in a new or overhauled
engine owing to breaking-in of the piston rings,
valve seats, etc. It drops as the engine
components wear down.
Service Manual Mitsubishi SL-Series diesel engines
Version 08/2004
COMPRESSION PRESSURE
OVERHAUL INSTRUCTIONS
5 COMPRESSION
PRESSURE

MEASUREMENT

5.1

Inspection

Check to make sure:
1. The crankcase oil level is correct, and the air
cleaner, starter and battery are all in normal
condition.
2. The engine is at the normal operating temperature.
5.2 Measurement
1. Move the control lever to a position for shutting off
fuel supply.
2. Remove all glow plugs from the engine. Install the
compression gauge and adaptor (ST332270)
combination to a cylinder on which the
compression pressure is to be measured.
3. Turn the engine with the starter and read the
gauge pressure at the instant the gauge pointer
comes to stop.
4. If the gauge reading is below the limit, overhaul the
engine.
CAUTION
• Be sure to measure the compression pressure
on all cylinders.
• The compression pressure varies with change of
engine rpm. This makes it necessary to check
engine rpm at the time of measuring the
compression pressure.
Engine speed, rpm
Compression pressure, kgf/
cm2 (psi) [kPa]
Maximum permissible difference
between average compression
pressure of all cylinders in one
engine, kgf/cm2 (psi) [kPa]
ENGLISH
MEASUREMENT
Standard Limit
290 --
SL 30 23
(427) (327)
[2 942] [2 256]
SL2 32 25
(455) (356)
[3 138] [2 452]
3 --
(42.7)
[294]
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