MOONEY INTERNATIONAL CORPORATION
M20V SERVICE AND MAINTENANCE MANUAL
Page
Date
14
MAR 2017
Rev Date
21-54-03 - DRIVE BELT ALIGNMENT PROCE-
DURE
1. STARTER/ACCESSORY DRIVE PULLEY AND
COMPRESSOR PULLEY
A. Place alignment gauge (Borrough’s Tool No.
8082A or equivalent) around starter/accessory drive
sheave/pulley assembly. The extended end of align-
ment gauge should overlay the upper portion of the
compressor sheave outer pulley assembly.
B. The alignment gauge alignment bar must fall
within 0.020 inches of the center of the compressor
sheave outer pulley groove.
C. If alignment bar is off center of groove by more
than 0.020 inches; estimate the number of 0.020 shims
necessary to correct the alignment.
D. Remove accessory drive sheave assembly and
place as many 0.020 shims, TCM P/N 646064- 20, on
starter/accessory drive shaft, as required, to achieve
the correct alignment between the starter/accessory
drive sheave/pulley assembly and compressor sheave
outer pulley assembly. When alignment is correct, the
extended arm of the alignment tool will fall into the cen-
ter of the bottom of the compressor outer pulley groove
within 0.020 inch.
E. Remove the alignment gauge from starter/ac-
cessory drive sheave/pulley assembly.
F. Torque the starter/accessory drive shaft 12
point, self- locking, nut to 450- 500 inch pounds. Lubri-
cate threads with clean 50 wt. engine oil prior to starting
nut on threads.
G. Full engagement of threads on nut, P/N
649924, is required.
-CAUTION-
Prevent engine rotation during tightening
procedures of starter/accessory drive nut.
2. IDLER PULLEY AND COMPRESSOR PULLEY
A. Place alignment gauge (Borrough’s Tool No.
8082A) around idler sheave/pulley assembly.
B. The alignment gauge alignment bar must fall
within 0.020 inches of the center of the compressor
sheave outer pulley groove.
C. If the extended end of alignment bar is off center
of groove by more than 0.020 inches, estimate the
number of 0.020 shims necessary to correct the align-
ment.
D. Remove idler sheave assembly and place as
many 0.020 shims, CMI P/N 643956- 20, between idler
sheave
and bearing as required to achieve correct alignment
between idler and compressor sheave outer pulley.
When alignment is correct, the extended arm will fall
into the center of the bottom of groove of compressor
outer pulley groove within 0.020 inch.
E. Re- install idler sheave assembly and torque
screw to 800- 850 in. lbs.
3. VERIFICATION OF PROPER ALIGNMENT FOR
ALL PULLEYS.
A. After torquing of all sheave assemblies, check
alignment of all pulleys to verify belt will not run with any
misalignment during engine operation.
B. Belt is ready for tensioning. See Section
21-54-04.
21-54-04 - DRIVE BELT TENSIONING PROCE-
DURE
1. Verify all compressor, starter/accessory drive and
idler pulley mounting hardware is tight and belt is prop-
erly aligned per Section 21-54-03.
2. Loosen jam nut on the adjusting bolt, adjusting bolt
and idler pulley slide nut (Fig. 21- 5). The idler pulley
slide nut should be loosened only enough to allow the
slide to move freely. For new belt installations, the ad-
justing bolt should only be turned out enough to allow
installation of the new belt.
3. Install new belt (for new belt installations only).
4. Slide idler pulley snugly against belt and tighten
adjusting bolt finger tight into its socket.
-NOTE-
At this stage, idler pulley sho uld be rotatable by
hand beneath belt.
5. Tighten adjusting bolt two full turns.
6. Secure adjusting bolt jam nut (275- 325 in. lbs.)
and idler pulley slide nut (300- 350 in. lbs.).
7. Confirm belt tension is 50- 70 lbs. by one of the fol-
lowing methods:
A. Use a direct reading belt tension gauge such as
Borrough’s Tool No. BT- 33- 73F. – OR
B. Measure belt deflection under a five (5) lb. load
at the center of the longest belt span. Correct deflection
is 0.3 - 0.4 inches.
-NOTE-
A spring loaded force gauge is required f or this
procedure.
8. If belt tension is not within the above tolerance,
loosen adjusting screw jam nut and idler pulley slide nut
and re- adjust the tension.
-NOTE-
One (1) full turn of adjusting screw results in
about a ten lb. change in belt tension.
-WARNING-
DO NOT OVER TIGHTEN BELT. Improper belt
tracking or tension may cause belt damage.
21-54-03
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