5-21. CRANKCASE (ENGINE HOUSING) MAINTENANCE INSTRUCTIONS - Continued
Visually inspect the engine housing (3) for cracks
or damaged threaded holes.
Check distance from cylinder seat to center of
crankshaft axis as follows:
Using vernier caliper, measure diameter of
opening for seal housing (flywheel side). Re-
cord ½ this measurement as X.
Measure distance from face of cylinder seat
to top dead center (TDC) of the opening for
seal housing. Record this measurement as Y.
If the sum of X + Y IS less than 2.9488 in.
(74.900 mm), Replace the engine housing.
Measure bore diameter for camshaft, Replace en-
gine housing if bore exceeds 0.8689 in. (22.070
If calculated radial end play of the crankshaft jour-
nal to the main front bearing (Para. 5-20), was de-
termined to exceed 0.0039 in. (0.10 mm), replace
the main front bearing (7).
If determination to send crankshaft to gen-
eral support maintenance for regrinding of
the bearing journals, consult Table 5-1, in
paragraph 5-20, for identification of under-
size main front bearing to install.
Inspect inside diameter surface of main front
bearing (7), installed in engine housing (3). Bear-
ing is manufactured with a galvanically applied
wear layer. Replace bearing if inside diameter ap-
pears shiny bronze in color.
If main front bearing (7) must be replaced, meas-
ure the bearing bore of engine housing (3) after
bearing removal. If bore exceeds 1.8104 in.
(45.985 mm), replace the engine housing (3).
Inspect studs (5 and 6) for loose fit in engine
housing or damaged threads. Tighten loose
studs. Replace studs found defective.
If main front bearing (7) is to be replaced, pro-
ceed as follows:
Lay engine housing on bed of arbor press
with main front bearing on top.
Set new main front bearing on top of the worn
bearing, aligning both the oil hole and ensur-
ing that the butt joint of new main front bear-
ing is aligned toward the oil filter mount.
Press the new main front bearing into the en-
gine housing, seating flush with the face of
housing. Use pressing sleeve (60 mm O.D.
with 39 mm pilot)