
03-39
SECTION 03 - ENGINE PREPARATION
CRANKSHAFT INSPECTION
Crankshaft Misalignment
and Deflection
Since it is an assembled crankshaft, it can be-
come misaligned or deflected. Crankshaft can be
twisted on center main journal, changing timing of
one cylinder in relation with the other, also chang-
ing the ignition timing for the PTO cylinder, and
the rotary valve timing for the MAG cylinder.
1. Main journal alignment here
Counterweights can also be twisted on connect-
ing rod journal on any or both cylinders.
1. Connecting rod journal alignment here
Crankshaft Alignment at Center Main
Journal
To accurately check crankshaft alignment, pro-
ceed as follows:
– Remove magneto housing cover.
– Remove MAG flywheel nut (and also the mag-
neto rotor for the 787 engine).
– Install Bombardier degree wheel (P/N 295 000
007) on crankshaft end. Hand-tighten nut only.
– Remove both spark plugs.
– Install a TDC gauge (P/N 295 000 143) in spark
plug hole on MAG cylinder side.
– Bring MAG piston at Top Dead Center.
– As a needle pointer, secure a wire with a cover
screw and a washer.
1. TDC gauge
2. Degree wheel
3. Hand tighten nut
4. Needle pointer
– Rotate degree wheel (NOT crankshaft) so that
needle pointer reads 360°.
– Remove TDC gauge and install on PTO side.
– Bring PTO piston at Top Dead Center.
Interval between cylinders must be exactly 180°
therefore, needle pointer must indicate 180° on
degree wheel (360° – 180° = 180°).
Any other reading indicates a misaligned crank-
shaft.
F01D1NA
1
F01D1NB
1
1
F01D4IA
3
2
4
Summary of Contents for Bombardier
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