Mercruiser 502 Magnum Engine Specifications
 |
 |
 |
 |
 |
 |
454 CID / 7.4L / 502 CID / 8.2L Engine Specifications
|
Unit of Measurement In. (mm) |
|
DISPLACEMENTÂ |
7.4L |
454 MAGNUMÂ |
502 MAGNUM / 8.2L |
|
 Bore |
4.25(108)Â |
4.46 (113.28) |
|
|
Stroke |
4.00 (101.6) |
||
|
Compression Ratio |
8.0:1Â |
8.6:1 |
8.75:1 |
|
Heads |
Cast Iron ( Oval Port )Â |
Cast Iron (Rectangular Port) |
|
|
Intake Manifold |
Cast Iron |
Aluminum With Brass Inserts-High Rise (See Note) |
|
|
Block |
Cast Iron (4 Bolt Main Bearing Caps)Â |
||
|
Rods |
Forged Steel |
||
|
Pistons |
Cast Aluminum |
Forged Aluminum |
|
|
Crankshaft |
Cast Steel |
Forged Steel |
|
|
Camshaft |
Cast Iron |
||
  Note: 7.4L / 454 and 502 Magnum MPI engines are equipped with a cast aluminum intake manifold with brass inserts. Â
  CYLINDER BORE
|
ENGINE |
7.4L |
454 MAGNUM |
502 MAGNUM/ 8.2LÂ |
||
|
Diameter |
4.2500-4.2507 (107.950-107.967) |
4.2451-4.2525 (107.826-108.013) |
4.4655-4.4662 (113.423-113.441) |
||
|
Out of Round |
Production |
.001 (0.025) Max |
|||
|
Service |
.002 (0.05) Max |
||||
|
Taper |
Production |
Thrust Side |
.0005 (0.0127) Max |
||
|
Relief Side |
.001 (0.0254) Max |
||||
|
Service |
.001 (0.02) Over Production |
||||
Â
PISTON
|
Clearance |
Production |
.0018-.0030 (0.0457-0.0762) |
.0025-.0037 (0.0635-0.0939) |
.0040-.0057 (0.1016-0.1447) |
|
Service |
.0018 (0.0457) Max |
.0075 (0.15) Max |
.0065 (0.16) Max |
Â
PISTON RING
|
ENGINE |
7.4LÂ |
454 MAGNUM |
502 MAGNUM 8.2L |
||||
|
Compression Â
|
Groove Side Clearance |
Production |
Top |
.0012-.0029 (0.044-0.081) |
.0017-.0032 (0.044-0.081) |
.0017-.0032 (0.044-0.081) |
|
|
2nd |
.0012-.0029 (0.044-0.081) |
.0017-.0032 (0.044-0.081) |
.0017-.0032 (0.044-0.081) |
||||
|
Service |
High Production Limit + .010(0.02) Maximum |
||||||
|
Gap |
Production |
Top |
.010-.018 (0.25-0.46) |
.011-.021 (0.28-0.53) |
|||
|
2nd |
.016-.024 (0.41-0.61) |
.016-.026 (0.41-0.66) |
|||||
|
Service |
High Limit Production + .010 (0.25) Maximum |
||||||
|
Oil |
Groove Side Clearance |
Production |
.0050-.0065 (0.127-0.165) |
||||
|
Service |
High Limit Production + .001(0.25) |
High Limit Production .005 (0.12) Max |
|||||
|
Gap |
Production |
.010-.030 (0.254-0.762) |
.020-.035 (0.508-0.889) |
.010-.030 (0.254-0.76) |
|||
|
Service |
High Limit Production + .001 (0.25) |
High Limit Production .005 (0.12) Max |
|||||
 PISTON PINÂ
|
ENGINEÂ |
7.4L |
454 MAGNUM |
502 MAGNUM |
|
|
Diameter |
.9895-.9897 (25.132-25.1371) |
.9895-.9898 (25.134-24.140) |
||
|
Clearance In Pin |
Production |
.0002-.0007 (0.0050-0.0177) |
.00025-.00035 (0.0064-0.0088) |
|
|
Service |
.001(0.025) Maximum |
|||
|
Fit In Rod |
.0021-.0031 (0.0533-0.0787) Interference |
.0008-.0016(0.021-0.040) Interference |
||
Â
454 CID / 7.4L / 502 CID / 8.2L Engine Specifications
|
Unit of Measurement In. (mm) |
 CRANKSHAFT
|
ENGINE |
7.4LÂ |
502 MAGNUM / 8.2L/454 MAGNUM |
||
|
Main Journal |
Diameter |
No. 1,2,3,4,5 |
2.7482-2.7489 (69.8042-69.8220) |
|
|
Taper |
Production |
.0004 (0.010) Max |
.0002 (0.005) Max |
|
|
Service |
.001 (0.02) Maximum |
|||
|
Out of Round |
Production |
.0002 (0.005) Maximum |
||
|
Service |
.001 (0.005) Maximum |
|||
|
Main Bearing Clearance |
Production |
No. 1,2,3,4 |
.0017-.0030 (0.043-0.076) |
.0017-.0030 (0.043-0.076) |
|
No. 5 |
.0025-.0038 (0.063-0.096) |
|||
|
Service |
No. 1 |
.001-.003 (0.03-0.07) |
.0010-.0015 (0.0254-0.0381) |
|
|
No. 2,3,4 |
.001-.003 (0.03-0.07) |
.0010-.0025 (0.0254-0.0635) |
||
|
No. 5 |
.0025-.0040 (.0635-.1016) |
|||
|
Crankshaft End Play |
.005-.0011 (0.127-0.279) |
.006-.0010 (0.15-0.2) |
||
|
Connection Rod Journal |
Diameter |
2.1990-2.1996 (55.8546-55.8698) |
||
|
Taper |
Production |
.0005 (0.0127) Maximum |
||
|
Service |
.001 (0.0254) Maximum |
|||
|
Out of Round |
Production |
.0005 (0.0127) Maximum |
||
|
Service |
.001 (0.0254) Maximum |
|||
|
Rod Bearing Clearance |
Production |
.0011-.0029 (0.028-0.074) |
||
|
Service |
.001 (0.0254) Max |
.003 (0.076) Max |
||
|
Rod Side Clearance |
.013-.023 (0.35-0.58) |
|||
|
Crankshaft Runout @ No. 3 main Bearing |
.0015 (0.038) Max |
.0035 (0.088) Max |
||
Â
454 CID / 7.4L / 502 CID / 8.2L Engine Specifications
|
Unit of Measurement In. (mm) |
  VALVE SYSTEMÂ
|
ENGINE MODEL |
7.4LÂ |
454 MAGNUMÂ |
502 MAGNUMÂ |
||
|
Lifter |
Hydraulic |
||||
|
Rocker Arm Ratio |
1.70 to 1 |
||||
|
Face Angle (Intake & Exhaust) |
45° |
||||
|
Seat Angle (Intake & Exhaust) |
46° |
||||
|
Seat Runout (Intake & Exhaust) |
.002 (0.05) Maximum |
||||
|
Seat Width |
Intake |
.0300-.0600 in. (0.7620-1.5240 mm) |
.03125-.0625 in. (0.79-1.58 mm) |
||
|
Exhaust |
.0600-.0950 in. (1.5240-2.4130 mm) |
.0625-.09375 in. (1.58-2.38 mm) |
|||
|
Stem Clearance |
Production |
Intake |
.0010-.0029 (0.0254-0.737) |
.0010-.0027 (0.025-0.069) |
|
|
Exhaust |
.0012-.0031 (0.0300-0.0787) |
.0010-.0027 (0.025-0.069) |
|||
|
Service |
Intake |
.001 (0.02) |
.003(0.07) |
.0037 (0.09) |
|
|
Exhaust |
.002 (0.05) |
.004 (0.10) |
.0049 (0.12) |
||
|
Stem Diameter |
Intake |
.372 (9.45) |
|||
|
Exhaust |
.372 (9.45) |
||||
|
Valve Margin (Intake and Exhaust) |
.0312 (0.79) |
||||
|
Valve Lash (Intake and Exhaust) |
Fixed Lash |
||||
Â
454 CID / 7.4L / 502 CID / 8.2L Engine Specifications
|
Unit of Measurement In. (mm) |
 VALVE SPRING
|
ENGINE MODEL |
7.4LÂ |
454 MAGNUM/ 502 MAGNUMÂ |
||
|
Valve Spring (Note 1) (Note 2) |
Free Length |
2.12 (53.9) |
2.15 (54.6) |
|
|
Pressure |
Closed at 1.88 in. (47.8 mm) |
Does Not Apply |
110 Lbs. (489 N) |
|
|
Closed at 1.838 in. (46.7 mm) |
71-79 Lbs. (316-351 N) |
Does Not Apply |
||
|
Open at 1.34 in. (35.1 mm) |
Does Not Apply |
316 Lbs. (1406 N) |
||
|
Open at 1.347 in. (34.120 mm) |
238-262 Lbs. (1059-1165 N) |
Does Not Apply |
||
|
Installed Height |
1.838 (46.7) |
1.88 (47.7) |
||
|
Damper or Damper Shield |
Free Length |
Does Not Apply |
1.86 (47.2) |
|
|
Approximate Number of Coils |
4 |
|||
|
Damper or Damper Shield |
Valve Spring Fit in Damper Shield |
.42-.094 (1.07-2.38) Interference |
Does Not Apply |
|
Note 1: 454/502/8.2L Models Only-Test spring pressure with inner and outer spring assembled.
Note 2: 7.4L Models Only Test spring pressure with damper shield installed.
Â
454 CID / 7.4L / 502 CID / 8.2L Engine Specifications
|
Unit of Measurement In. (mm) |
 ROLLER TAPPET CAMSHAFT
|
ENGINE MODELÂ |
7.4L |
454 MAGNUM 502 MAGNUM 8.2L |
|
|
Lobe Lift + .020 (0.051) |
Exhaust |
.284 (7.214) |
.342 (8.687) |
|
Intake |
.282 (7.163) |
.342 (8.687) |
|
|
Duration at .050 In. (1.27 mm) Cam Lift |
Exhaust |
209° |
227° |
|
Intake |
209° |
211° |
|
|
Journal Diameter |
1.94282-1.9492 (49.485-49.509) |
||
|
Journal Out Of Round |
.001 (0.025) Maximum |
||
|
Camshaft Runout |
.002 (0.051) Maximum |
||
|
Timing Chain Deflection |
.375 (9.5) from taut position [total .75 (19)] |
||
 FLYWHEELÂ
|
Runout |
.008 (0.203) Maximum |
CYLINDER HEAD
|
Gasket Surface Flatness |
.004 (0.1016) Overall Maximum .003 (0.076) within a 6 in. (152 mm) Span |
.007 (0.178) Overall Maximum .003 (0.076) within a 6 in. (152 mm) Span |
Â