Mercury MerCruiser MCM 454 Mag MPI Service Manual page 268

454 CID (7.4L) / 502 CID (8.2L)
WITH CRANKSHAFT REMOVED
1. Remove and inspect the crankshaft as outlined.
2. Remove the main bearings from the cylinder block and main bearing caps.
3. Coat bearing surfaces of new, correct size, main bearings with oil and install in the cylin-
der block and main bearing caps.
4. Install the crankshaft.
WITHOUT CRANKSHAFT REMOVED
IMPORTANT: Inspect bearing caps for orientation marks prior to removal. If no mark-
ings exist, make suitable marks before disassembly so that they can be reinstalled
in their original locations.
1. With oil pan, oil pump and spark plugs removed, make suitable marks on cap and
remove cap on main bearing requiring replacement. Remove bearing from cap.
2. Install main bearing remover/installer in oil hole in crankshaft journal. If tool is not avail-
able, a cotter pin may be bent, as shown, to do the job.
3. Rotate the crankshaft clockwise as viewed from the front of engine. This will roll upper
bearing out of block.
4. Oil new selected size upper bearing and insert plain (no notched) end between crank-
shaft and indented or notched side of block. Rotate the bearing into place and remove
tool from oil hole in crankshaft journal.
5. Oil new lower bearing and install in bearing cap.
6. Install main bearing cap with marks made on disassembly (or arrows, if present) pointing
toward front of engine.
7. Torque all main bearing caps, EXCEPT THE REAR MAIN CAP as follows:
7.4L MPI
454/502/8.2L MPI
8. Torque REAR MAIN BEARING CAP to 10-12 lb-ft (14-16 Nm); then tap end of crank-
shaft, first rearward then forward with a lead hammer. This will line up rear main bearing
and crankshaft thrust surfaces. Then torque rear main bearing cap to:
7.4L MPI
454/502/8.2L MPI
Index
Page 3A-64
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a - Main Bearing Remover / Installer (J-8080)
b - Cotter Pin
a
102 lb-ft (138 Nm)
110 lb-ft (149 Nm)
102 lb-ft (138 Nm)
110 lb-ft (149 Nm)
SERVICE MANUAL NUMBER 23
b
72556
90-861326--1 MARCH 1999