MerCruiser GM4 Service Manual page 132

Camshaft Bearings
Removal
Camshaft bearings can be replaced while engine is
disassembled for overhaul or without complete disas-
sembly. To replace bearings without complete disas-
sembly, remove camshaft and crankshaft, leaving
cylinder heads attached and pistons in place. Before
removing crankshaft, fasten connecting rods against
sides of engine so that they will not interfere while re-
placing camshaft bearings.
9. With camshaft and crankshaft removed, drive
camshaft rear plug from cylinder block.
NOTE: This procedure is based on removal of bear-
ings from center of engine first, thus requiring a mini-
mum amount of turns to remove all bearings.
1. Using camshaft bearing remover and installer set
(J-6098-01) (with nut and thrust washer installed
to end of threads), position pilot in front camshaft
bearing and install puller screw through pilot.
2. Install tool with shoulder toward bearing. Be sure
a sufficient amount of threads are engaged.
3. Using two wrenches, hold puller screw while turn-
ing nut. When bearing has been pulled from bore,
remove tool and bearing from puller screw.
4. Remove remaining bearings (except front and
rear) in same manner. It will be necessary to posi-
tion pilot in rear camshaft bearing to remove rear
intermediate bearing.
5. Assemble driver on driver handle and remove
front and rear camshaft bearings by driving to-
ward center of cylinder block.
Index
3A - 42 - ENGINES
Inspection
Clean camshaft bearing bores in cylinder block with
solvent and blow out with compressed air. Be sure
grooves and drilled oil passages are clean.
Installation
! CAUTION
OIl holes in bearings must line up with oil holes
in cylinder block. Oil hole is on top side of bearing
shell and cannot be seen during installation, so
first align bearing shell oil hole with oil hole in
bore and mark opposite side of bearing and block
at bore to easily position oil hole during installa-
tion.
IMPORTANT: Front bearing must be driven
approximately .125 in. (3 mm) behind the block
face to uncover oil hole to timing gear oil nozzle.
IMPORTANT: All camshaft bearings are not the
same. Be sure to install bearings in proper loca-
tions (Indicated by bearing manufacturer) and to
position bearings as follows (directional refer-
ences are in reference to engine in its normal op-
erating position):
Lubricate outer surface of new camshaft bearings
with engine oil to ease installation.
1. Installing intermediate and center bearings:
a. Install nut and thrust washer all the way onto
puller screw, then position pilot in front cam-
shaft bearing bore and insert screw through
pilot.
90-816462 2-695