MerCruiser 454 MAGNUM Manual
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MerCruiser 454 MAGNUM Manual

MerCruiser 454 MAGNUM Manual

7.4l/8.2l
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ENGINE
3
A
72851
454 CID (7.4L) / 502 CID (8.2L)
Index
90-823224--2 796
454 CID (7.4L) / 502 CID (8.2L) - 3A-–3

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Summary of Contents for MerCruiser 454 MAGNUM

  • Page 1 ENGINE 72851 454 CID (7.4L) / 502 CID (8.2L) Index 90-823224--2 796 454 CID (7.4L) / 502 CID (8.2L) - 3A-–3...

  • Page 2: Table Of Contents

    Table of Contents Page Page Torque Specifications ..... 3A-1 Inspection ......3A-31 Special Tools .
  • Page 3 Page Cleaning and Inspection ....3A-54 Installation ......3A-54 Timing Chain and Sprocket .
  • Page 4 THIS PAGE IS INTENTIONALLY BLANK Index 3A-0 - 454 C.I.D. (7.4L) / 502 C.I.D. (8.2L) 90-823224--2 796...

  • Page 5: Torque Specifications

    Remote Oil Connector (1/2 in. x 13) Rocker Arm Cover Rocker Arm Bolts 7.4L/454 454 Magnum/502 Note: 7.4L / 454 and 502 Multi-Port engines, Torque intake manifold fasteners to 25-30 Lb. Ft. (34-41 N·m). Index 90-823224--2 796 454 CID (7.4L) / 502 CID (8.2L) - 3A-1...
  • Page 6 Torque Specifications (Continued) DESCRIPTION Lb. Ft. Remote Oil Filter Adapter Nut/Fitting Seawater Pump Brace Seawater Pump Bracket Spark Plugs Starter Motor Thermostat Housing Torsional Damper Transmission To Housing Water Circulating Pump Water Temperature Sender Index 3A-2 - 454 C.I.D. (7.4L) / 502 C.I.D. (8.2L) 90-823224--2 796...

  • Page 7: Special Tools

    Special Tools MERCURY MARINE SPECIAL TOOLS DESCRIPTION PART NUMBER Piston Ring Expander 91-24697 Engine Coupler Wrench 91-35547 KENT-MOORE SPECIAL TOOLS DESCRIPTION PART NUMBER Valve Spring Compressor (Head on) J5892 Valve Spring Compressor (Head off) J8062 Valve Spring Tester J8056 Valve Guide Cleaner J8101 Carbon Remover Brush J8089...

  • Page 8: Gen V And Gen Vi (Except 7.4L Gen Vi) Engine Specifications

    Note 3: Serial numbers OD838819 thru OF800699 are equipped with cast aluminum intake manifolds. CYLINDER BORE IMPORTANT: 7.4L Bravo Three engines with engine code UB with serial number OF1589289 and lower have forged pistons. The piston specifications for the 454 Magnum must be used. 502 MAGNUM/ ENGINE 7.4L...
  • Page 9 Gen V And Gen VI (Except 7.4L Gen VI) Engine Specifications Unit of Measurement In. (mm) PISTON RING 502 MAGNUM ENGINE 7.4L 454 MAGNUM 8.2L .0012-.0029 .0017-.0032 .0017-.0032 (0.0305-0.0737) (0.044-0.081) (0.044-0.081) Groove Groove Production Production .0012-.0029 .0017-.0032 .0017-.0032 Side (0.0305-0.0737) (0.044-0.081)
  • Page 10 Gen V And Gen VI (Except 7.4L Gen VI) Engine Specifications Unit of Measurement In. (mm) CRANKSHAFT ENGINE 7.4L / 454 MAGNUM 502 MAGNUM / 8.2L Diameter No.1,2,3,4,5 2.7482-2.7489 (69.8042-69.8220) Production .0002 (0.005) Max Taper Taper Main Main Service .001 (0.02) Max...
  • Page 11 Gen V And Gen VI (Except 7.4L Gen VI) Engine Specifications Unit of Measurement In. (mm) VALVE SYSTEM 502 MAGNUM ENGINE MODEL 7.4L 454 MAGNUM 8.2L Lifter Hydraulic Rocker Arm Ratio 1.70 to 1 Face Angle (Intake & Exhaust) Seat Angle (Intake & Exhaust) Seat Runout (Intake &...
  • Page 12 Gen V And Gen VI (Except 7.4L Gen VI) Engine Specifications Unit of Measurement In. (mm) VALVE SPRING 454 MAGNUM ENGINE MODEL 7.4L 502 MAGNUM 8.2L Free Length 2.12 (53.9) 2.15 (54.6) Closed at Does Not 110 Lbs. 1.88 in. (47.8 mm)
  • Page 13 Gen V And Gen VI (Except 7.4L Gen VI) Engine Specifications Unit of Measurement In. (mm) HYDRAULIC FLAT TAPPET CAMSHAFT 454 MAGNUM ENGINE MODEL 7.4L 502 MAGNUM 8.2L Exhaust .271 (6.683) .300 (7.62) Lobe Lift Lobe Lift .002 (0.051) 002 (0 051) Intake .282 (7.163)

  • Page 14: 7.4L Gen Vi Engine Specifications

    7.4L Gen VI Engine Specifications Unit of Measurement In. (mm) Displacement 454 CID (7.4L) Bore 4.25 (108) Stroke 4.00 (101.6) Compression Ratio 8.0:1 Heads Cast Iron (Oval Port) Intake Manifold Cast Iron Block Cast Iron (4 Bolt Main Bearing Caps) Rods Forged Steel Pistons...
  • Page 15 7.4L Gen VI Engine Specifications Unit of Measurement In. (mm) PISTON RING Production .0012-.0029 (0.0304-0.0737) Groove Side Side Clearance Service High Production Limit + .010 (0.0254) Max .010-.018 (0.254-0.457) Production Production .016-.024 (0.406-0.6096) Service High Limit Production + .010 (0.254) Max Groove Production .0050-.0065 (0.1270-0.1651)
  • Page 16 7.4L Gen VI Engine Specifications Unit of Measurement In. (mm) CRANKSHAFT Diameter No. 1, 2, 3, 4, 5 2.7482-2.7489 (69.8040-69.8220) Production .0004 (0.0102) Max Taper Taper Main Main Service .001 (0.0254) Max Journal Journal Production .0004 (0.0102) Max Out of Round Out of Round Service .001 (0.0254) Max...
  • Page 17 7.4L Gen VI Engine Specifications Unit of Measurement In. (mm) VALVE SYSTEM Lifter Hydraulic Roller Rocker Arm Ratio 1.70 to 1 Face Angle (Intake & Exhaust) Seat Angle (Intake & Exhaust) Seat Runout (Intake & Exhaust) .002 (0.05) Max Intake .0300-.0600 (0.7620-1.5240) Seat Width Seat Width...
  • Page 18 7.4L Gen Gen VI Engine Specifications Unit of Measurement In. (mm) FLYWHEEL Runout .008 (0.203) Max CYLINDER HEAD .004 (0.1016) Overall Maximum Gasket Surface Flatness .003 (0.076) within a 6 in. (152mm) Span Exhaust .284 (7.214) Lobe Lift Lobe Lift .020 (0.051) 020 (0 051) Intake...

  • Page 19: General

    7.4L Engine Identification Gen V and VI Cylinder heads are identified by their The MerCruiser Model can be determined by looking smaller and rounded intake ports. at the last two letters of the engine code stamped into the cylinder block. This code number is stamped on...

  • Page 20: Engine Rotation

    Engine Rotation Camshaft and Drive Engine rotation terminology at times has caused con- Flat tappet camshafts made of cast iron and roller lift- fusion. To clarify, engine rotation is determined by ob- er camshaft are made of steel. All camshafts are driv- serving flywheel rotation from the rear (transmission en at one-half crankshaft speed by a timing chain and or stern drive end) of the engine looking forward (wa-...

  • Page 21: Intake Manifold

    Intake Manifold bore. Some of the oil is then used to lubricate cam- shaft bearings. The remainder of the oil is routed to the valve lifter oil galleries and No. 1, 2, 3, and 4 CARBURETED AND THROTTLE BODY crankshaft main bearings by means of individual oil INJECTION passages which intersect with the annular grooves.

  • Page 22: Bearing Failures

    Bearing Failures 70436 Scratched By Dirt 70436 a - Scratches b - Dirt Imbedded In Bearing Material Radius Ride a - Worn Area 70436 70436 Tapered Journal a - Overlay Gone From Entire Surface Improper Seating a - Bright Or Polished Sections 70436 Lack Of Oil 70436...

  • Page 23: Piston Failures

    Piston Failures PRE-IGNITION CAUSES 1. Hot spots in the combustion chamber from glow- ing deposits (due in turn to the use of improper Pre-Ignition oils and/or fuels). Pre-ignition is abnormal fuel ignition, caused by com- 2. Overheated spark plug electrodes (improper bustion chamber hot spots.

  • Page 24: Engine Mounts

    NOTE:Engine failures, which result from the forego- Engine Mounts ing conditions, are beyond the control of MerCruiser; therefore, no warranty will apply to failures which oc- cur under these conditions. 72425 Detonation Damage 72317 Front Mount - All MCM (Stern Drive) Models...
  • Page 25 Engine Mounts (Continued) 73055 Flywheel Housing - All MIE (Inboard) Models 71789 Rear Mount Assembly - MIE 7.4L/8.2L with Hurth Down Angle and V-Drive Transmission 73056 Rear Mount Assembly - MIE 7.4L/8.2L with Borg-Warner In-Line Transmission 72319 Rear Mount Assembly - MIE 7.4L with Borg-Warn- er Remote V-Drive Transmission a - Rubber Insert Cannot Be Removed 72319...

  • Page 26: Rocker Arm Cover

    Rocker Arm Cover Intake Manifold NOTICE Removal For repair procedures on Fuel Injection Engines, refer to Section 5C. On Engines with Center Exhaust Outlet Exhaust Manifolds: It may be necessary to remove exhaust manifold before removing rocker arm cover. Refer to Removal Section 7B for removal.

  • Page 27: Installation

    Be sure to install gasket with marked side up. Both gaskets are identical. All MerCruiser V-8 GM engines that have “au- tomatic” carburetor chokes must use an in- take gasket that has an opening for the ex- haust crossover port in the intake manifold.

  • Page 28: Rocker Arm / Push Rod

    6. Connect all electrical leads. 1. Install push rods in their original locations. Be sure push rods seat in lifter socket. 7. Connect hoses to thermostat housing. 2. Install rocker arms, rocker arm balls and rocker 8. Install fuel line and sight tube to carburetor and arm bolts in their original locations.

  • Page 29: Locating Noisy Lifters

    Hydraulic valve lifters require little attention. Lifters In most cases, where noise exists in one or more lift- are extremely simple in design. Normally, readjust- ers, all lifter units should be removed, disassembled, ments are not necessary and servicing requires only cleaned in solvent, reassembled and reinstalled in that care and cleanliness be exercised in the handl- engine.

  • Page 30: Installation

    Installation 3. Using valve spring compressor as shown, com- press valve spring and remove valve locks. IMPORTANT: It is recommended that the engine oil be changed and a new oil filter be installed whenever servicing valve lifters or camshaft. IMPORTANT: Before installing lifters, coat the bottom of the lifter with engine oil.

  • Page 31: Valve Assembly (Exploded View)

    Valve Assembly (Exploded View) 72278 454 Magnum / 502 Magnum/ 8.2L 1 - Valve Lock 2 - Retainer 3 - Oil Shield 72279 4 - Inner Spring 5 - Outer Spring 7.4L Only 6 - Shim 7 - Intake Valve...

  • Page 32: Installation - Head Installed

    Installation - Head Installed 454 MAGNUM / 502 MAGNUM / 8.2L 1. Place shim on valve spring seat. 7.4L 2. If taken apart, reassemble damper and valve 1. Place rotator or shim on valve spring seat. spring as shown. Make sure tighter wound coils of spring and damper are on the same end.

  • Page 33: Cylinder Head

    Cylinder Head Installation CAUTION Removal DO NOT use sealer on head gaskets. 1. Drain engine cooling system. 1. Place head gasket in position over dowel pins. 2. Remove as outlined: 2. Carefully set cylinder head in place over dowel a. Exhaust manifolds. pins.

  • Page 34: Cylinder Head And Valve Conditioning

    7. Follow procedures in Section 6A or 6B of this Cleaning manual: 1. Clean push rods and rocker arm assemblies. Seawater Cooled Models: Provide for adequate 2. Clean carbon from valves using a wire wheel. water supply to seawater pickup (see Section 6A).

  • Page 35: Inspection

    Inspection b. Holding valve head off seat about 1/16 in. (2 mm), move valve stem back and forth in di- 1. Inspect cylinder heads for cracks in exhaust rection shown. Compare stem clearance with ports, water jackets, and combustion chambers specifications.

  • Page 36: Valve Springs - Checking Tension

    1. Measure valve stem diameter of old valve being Valve Seat Repair replaced and select proper size valve guide Valve seat reconditioning is very important, since reamer from chart below. seating of valves must be perfect for engine to deliver maximum power and performance.

  • Page 37: Valve Grinding

    Valve Grinding Reassembly Valves that are pitted must be refaced to the proper 1. Lubricate valve guides and valve stems with en- angle. Valve stems which show excessive wear, or gine oil. valves that are warped excessively, must be re- 2.
  • Page 38 5. Slowly release tool, making sure valve locks seat properly in grooves of valve stem. 72278 454 Magnum / 502 Magnum / 8.2L 72279 7.4L a - Valve Lock b - Retainer 1 - Valve Lock c - Oil Shield...
  • Page 39 6. Check installed height of valve springs using a narrow, thin scale cutaway as shown. Measure from spring seat to top of valve spring, as shown. If measurement exceeds specified height, install a valve spring shim and recheck. DO NOT shim valve springs to give an installed height less than the minimum specified.

  • Page 40: Dipstick Specifications

    Dipstick Specifications All Engines UNIT OF MEASUREMENT In. (mm) (13) (13) (13) 16-43/64 15-1/8 33-1/2 (423) (384) (849) 35-1/4 17-13/64 19-7/64 (895) (437) (485) FULL FULL FULL 59/64 19/32 (23) (15) (13) 72341 a - MCM Engines (805567) b - MIE Velvet Drive In Line Transmissions (821503-3) c - MIE All Transmissions Except Velvet Drive (821503-4) Index 3A-36 - 454 C.I.D.

  • Page 41: Oil Pan

    Oil Pan IMPORTANT: Quicksilver RTV Sealer sets up in about 15 minutes. Be sure to complete assembly promptly. Removal 1. Drain crankcase oil. 2. Remove dipstick and tube, or tubes, if equipped with two. Note shape of port and starboard tubes as shown following to aid in reassembly.

  • Page 42: Oil Pump 3A-38

    IMPORTANT: DO NOT move or disturb the orien- The oil pump consists of two gears and a pressure tation of fitting on bottom of pan or incorrect oil regulator valve enclosed in a two-piece housing. Oil level readings may be obtained. pump is driven by distributor shaft which is driven by a helical gear on camshaft.

  • Page 43: Cleaning And Inspection

    Cleaning and Inspection Installation 1. Wash all parts in cleaning solvent and dry with 1. Install pump, with extension shaft, to rear main compressed air. bearing, aligning extension shaft with distributor drive shaft. 2. Inspect pump body and cover for cracks or ex- cessive wear.

  • Page 44: Installation

    IMPORTANT: Do not use a universal claw type IMPORTANT: Be sure to install threaded rod in puller to remove torsional damper (in next step) crankshaft at least 1/2 in. (13 mm) to prevent dam- as outside ring of torsional damper is bonded in age to threads.

  • Page 45: Crankcase Front Cover/Oil Seal

    Crankcase Front Cover/ 2. Install new seal with open end of seal inward (lip of seal toward inside of engine), using crankcase Oil Seal front cover seal installer. Drive seal in until it just bottoms out. Do not use excessive force. Oil Seal Replacement (Without Removing Front Cover) REMOVAL...

  • Page 46: Installation

    Installation Flywheel 1. Install oil seal in cover with lip of seal toward in- side of engine, using crankcase front cover seal Removal installer. Support cover around seal area with ap- propriate tool as shown. 1. Remove engine from boat. 2.

  • Page 47: Inspection

    c. Maximum runout - .008 in. (0.203 mm). 72352 Drive Shaft Extension Coupler Inspection 72353 a - .008 in. (0.203 mm) Max. Runout 1. Inspect splines in drive plate or coupler for wear. b - Pus Flywheel And Crankshaft Forward As Far As It Will Go When Taking Reading 2.

  • Page 48: Rear Main Oil Seal

    Rear Main Oil Seal Cleaning and Inspection Clean crankshaft/seal running surface and seal re- The rear crankshaft oil seal can be replaced without tainer. removing the oil pan or rear main bearing cap from engine. IMPORTANT: Correct rotation oil seal must be used to prevent oil leak.

  • Page 49: Installation

    Installation Checking Clearances 1. Apply Quicksilver Perfect Seal to engine block/ To obtain accurate measurements while using Plasti- seal mating surface. Apply grease to seal lips. gage, or its equivalent, engine must be out of the boat and upside down so crankshaft will rest on the upper 2.

  • Page 50: Replacement

    4. Remove bearing cap. The flattened gauging 8. Proceed to the next bearing. After all bearings plastic will be found adhering to either the bearing have been checked, rotate the crankshaft to see cap or journal. that there is no excessive drag. When checking No.

  • Page 51: Connecting Rod Bearings

    WITH CRANKSHAFT REMOVED 3. Rotate the crankshaft clockwise as viewed from the front of engine. This will roll upper bearing out 1. Remove and inspect the crankshaft as outlined. of block. 2. Remove the main bearings from the cylinder 4. Oil new selected size upper bearing and insert block and main bearing caps.
  • Page 52 4. Measure the crankpin for out-of-round or taper IMPORTANT: Do not turn the crankshaft with the with a micrometer. If not within specifications, re- gauging plastic installed. place or recondition the crankshaft. If within specifications and a new bearing is to be in- stalled, measure the maximum diameter of the crankpin to determine new bearing size required.

  • Page 53: Connecting Rod/Piston Assembly

    8. When all connecting rod bearings have been in- IMPORTANT: Before ridge and/or deposits are re- stalled, tap each rod lightly (parallel to the crank- moved, turn crankshaft until piston is at bottom pin) to make sure they have clearance. of stroke and place a cloth on top of piston to col- lect cuttings.

  • Page 54: Disassembly

    Disassembly 5. Slip outer surface of a new top and second com- pression ring into respective piston ring groove Disassemble piston from connecting rod using piston and roll ring entirely around the groove to make pin remover as shown. Follow instructions supplied sure that ring is free as shown.

  • Page 55: Reassembly

    Connecting rod bearing tangs are always to- ward outside of cylinder block. 72553 454 Magnum / 502 Magnum / 8.2L a - Valve Relief - Toward Center Of Engine 72368 a - Rod Bearing Tangs Index 90-823224--2 796 454 CID (7.4L) / 502 CID (8.2L) - 3A-51...
  • Page 56 1. Assemble piston to connecting rod using piston 3. Measure gap between ends of ring with a feeler pin remover as shown. Follow instructions gauge as shown. supplied with kit. 72372 4. If gap between ends of ring is below specifica- tions, remove ring and try another for fit.

  • Page 57: Installation

    Installation IMPORTANT: Be sure to install new pistons in same cylinders for which they were fitted, and used pistons in same cylinder from which they IMPORTANT: Cylinder bores must be clean be- were removed. Each connecting rod and bearing fore piston installation. Clean with a light honing, cap should be marked, beginning at front of en- as necessary.

  • Page 58: Crankshaft

    Crankshaft Cleaning and Inspection 1. Wash crankshaft in solvent and dry with com- pressed air. Removal 2. Measure main bearing journals and crankpin di- 1. Remove engine from boat. mensions with a micrometer for out-of-round, ta- per or undersize (see “Specifications”). 2.
  • Page 59 3. Carefully lower crankshaft into place. Be careful Timing Chain and Sprocket not to damage bearing surface. 4. Check clearance of each main bearing, following Removal procedure outlined under “Main Bearings.” If bearing clearances are satisfactory, apply engine 1. Remove torsional damper, oil pan and crankcase oil to journals and bearings.
  • Page 60 Cleaning and Inspection Installation 1. Clean all parts in solvent and dry with com- 1. Using crankshaft gear and sprocket installer, as pressed air. shown, install sprocket on crankshaft. 2. Inspect timing chain for wear and damage. 3. Inspect sprockets for wear and damage. Installation 1.
  • Page 61 4. The deflection is the difference between these 1. Remove valve mechanism as outlined. two measurements. If the deflection exceeds 3/4 2. Adapt dial indicator to cylinder head by tempo- in. (19 mm), timing chain should be replaced. rarily installing suitable stud in bolt hole. Position indicator with ball socket adaptor tool, from Lift In- dicator Tool Kit, on push rod.
  • Page 62 Removal Also check camshaft for alignment with V-blocks and dial indicator which indicates exact amount camshaft 1. Remove valve lifters as outlined. is out of true. If out more than .002 in. (0.051 mm) (dial indicator reading) camshaft should be replaced. 2.
  • Page 63 2. Using camshaft bearing remover and installer set Inspection (J-6098-01) (with nut and thrust washer installed Clean camshaft bearing bores in cylinder block with to end of threads), position pilot in front camshaft solvent and blow out with compressed air. Be sure bearing and install puller screw through pilot.
  • Page 64 b. Index front bearing (as explained in “Impor- 7. Measure cylinder walls for taper, out-of-round or tant” above), and drive it into position with excessive ridge at top of ring travel. This should tool. Check position of oil hole(s) in bearing to be done with a dial indicator or inside micrometer.
  • Page 65 3. If cylinders have less than .005 in. (0.127 mm) ta- per or wear, they can be conditioned with a hone and fitted with high limit standard size piston. A cylinder bore of more than .005 in. wear or taper may not clean up entirely when fitted to a high lim- it piston.
  • Page 66 IMPORTANT: Handle pistons with care and do not b. Measure piston diameter at skirt across cen- attempt to force them through cylinder until cyl- ter line of piston pin as shown. inder is honed to correct size, as this type piston can be distorted by careless handling.
  • Page 67 Oil Filter By-Pass Valve and 6. Wipe out valve chamber in cylinder block to re- move any foreign material. Adaptor 7. Install by-pass valve (if replaced) and connector. Torque adaptor nut to 20 lb. ft. (27 N·m). CAUTION 8. Lubricate adaptor seal with engine oil. Install hose fitting and torque to specifications.
  • Page 68 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 3A-64 - 454 C.I.D. (7.4L) / 502 C.I.D. (8.2L) 90-823224--2 796...
  • Page 69 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 90-823224--2 796 454 CID (7.4L) / 502 CID (8.2L) - 3A-65...
  • Page 70 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 3A-66 - 454 C.I.D. (7.4L) / 502 C.I.D. (8.2L) 90-823224--2 796...
  • Page 71 THIS PAGE IS INTENTIONALLY BLANK TO ALLOW FOR CORRECTIONS OR ADDITIONS AT A LATER DATE Index 90-823224--2 796 454 CID (7.4L) / 502 CID (8.2L) - 3A-67...

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502 magnum

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