70-20-02
ALL ú ú C01 Page 204 ú Nov 15/91
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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CFM56 ENGINES
737-300/400/500/ /MAINTENANCE MANUAL ////////////////////////
(a)
When you use an offset extension wrench, such as a crowfoot extension, with a torque wrench, you change the effective length of the torque wrench.
(b)
When you calibrate the torque wrench (when an extension wrench is used), the torque (the value that shows on the scale or dial of the torque wrench) can be different from the correct torque you apply to the nut or bolt. 1) The procedure to calculate the adjustment is as follows:
a) When you add or decrease to the effective length of the extension wrench, it is found by its position on the torque wrench.
b) When the extension wrench is pointed in the same direction as the torque wrench, add the effective length of the extension (E) to the effective length of the torque wrench (L) to give (L+E).
c) When the extension is pointed to the rear of the handle of the torque wrench, subtract the effective length of the extension (E) from the effective length of the torque wrench (L) to give (L-E).
d) When the extension is pointed at right angles to the torque wrench, the effective length does not change.
e) The effective length of the torque wrench changes, and a different figure must be used for each type of torque wrench.
f) Find the effective length of the extension when you measure it from the center of the drive opening to the center of the wrench opening.
g) Multiply the required torque (T) by the effective length of the torque wrench (L). h) Divide this product by (L+E) or (L-E) as determined from Fig. 201. i) The quotient is the gage or scale value necessary to
get the required torque. ~.............................................................................. | Example: |
_______Required torque = 265 inch-pounds (30 newton-meters) | Effective length of torque wrench = 8.4 inches (213 mm) | | Effective length of the extension = 1.5 inches (38 mm) | | | | Then: (Required torque) x (L) = 265 x 8.4 = 2226 | | (30 x 213 = 6390) | | | | (L+E) = 9.9 inches (251 mm) | | | | 2226/9.9 = 225 inch-pounds | | (6390/251 = 25.5 newton-meters) | | | | Thus: A gage value of 225 inch-pounds makes for a required | | torque of 265 inch-pounds. | | (A gage value of 25.5 newton-meters for a required | | torque of 30 newton-meters). | 2..............................................................................1
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70-20-02
ALL ú ú C01 Page 205 ú Nov 12/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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CFM56 ENGINES
737-300/400/500/ /MAINTENANCE MANUAL ////////////////////////
S 912-006-C00
(5) Approved Torque Values
(a)
Approved torque values for the bolts and nuts (does not include reduced head bolts) given in Fig. 202 (pound-inches) and Fig. 203 (N.m).
(b)
For the reduced head bolts, use torque values given in Fig. 204.
(c)
Approved torque values for the studs and stepped studs in aluminum or magnesium given in Fig. 205.
(d)
Approved torque values for flared tubes and hose fittings are given in Fig. 206.
S 912-007-C00
(6) Tighten the Plugs and Tube Fittings (Fig. 207 and 208).
(a) Assembly procedures change, by the special type of plug or tube fitting that you use. 1) The types you usually find include:
a) Non-positioning plugs and unions, with O-rings or other
packing that compresses for seals. b) Positioning fittings, with or without back-up washers. c) Universal bulkhead fittings, held in position by
locknuts.
(b) Calculate the torque values (Fig. 208) on the correct assembly of the fittings as given below. 1) The Installation of O-rings (packings) on the fittings.
a) When the ratio of the O-ring (packing) diameter to the cross section is larger than 20, use a conic sleeve turned on the fitting until the O-ring (packing) can be moved into a groove of a fitting without damage to it.
b) For the diameter ratios less than 20, a conic sleeve is not necessary.
NOTE: Not when the O-ring (packing) must be rolled on
____ the threads or splines.
c) Lubricate the O-ring (packing) with petrolatum. d) Move the O-ring in the groove of the fitting. 2) Lubricated Surfaces. a) Do not use lubricant on all threads or friction surfaces unless specified differently.
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