Inspection; Installation; Camshaft Bearings; Removal - Mercury MerCruiser MCM 454 Mag MPI Service Manual

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SERVICE MANUAL NUMBER 23

Inspection

Measure camshaft bearing journals with a micrometer for out-of-round condition. If journals

exceed .001 in. (0.025 mm) out-of-round, camshaft should be replaced.

Also check camshaft for alignment with V-blocks and dial indicator which indicates exact

amount camshaft is out of true. If out more than .002 in. (0.051 mm) (dial indicator reading)

camshaft should be replaced.

1. Install camshaft as follows:

2. Install crankcase front cover and valve lifters as outlined.

Camshaft bearings can be replaced while engine is disassembled for overhaul or without

complete disassembly. To replace bearings without complete disassembly, remove cam-

shaft 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 replacing camshaft bearings.

1. With camshaft and crankshaft removed, drive camshaft rear plug from cylinder block.

NOTE: This procedure is based on removal of bearings from center of engine first, thus

requiring a minimum amount of turns to remove all bearings.

2. Using camshaft bearing remover and installer set (J-6098-01) (with nut and thrust

3. Install tool with shoulder toward bearing. Be sure a sufficient amount of threads are

4. Using two wrenches, hold puller screw while turning nut. When bearing has been pulled

90-861326--1 MARCH 1999

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Checking Camshaft Alignment

a. Install two 5/16-18 x 5 in. bolts in camshaft bolt holes, then lubricate camshaft jour-

nals with engine oil and install camshaft, being careful not to damage bearings.

b. Lubricate camshaft lobes with General Motors Cam and Lifter Prelube or equivalent.

c. Install timing chain or gears as outlined.

washer installed to end of threads), position pilot in front camshaft bearing and install

puller screw through pilot.

from bore, remove tool and bearing from puller screw.

454 CID (7.4L) / 502 CID (8.2L)

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