Mercury MerCruiser MCM 502 Mag MPI User Manual

454 CID (7.4L) / 502 CID (8.2L) SERVICE MANUAL NUMBER 23
Page 3A-10
90-861326--1 MARCH 1999
454 Mag / 502 Mag / 8.2L (Except 7.4L MPI L-29) Engine Specifications
(Continued)
VALVE SYSTEM
MODEL 454 MAG 502 MAG / 8.2L
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) Max
Seat Width
Intake 1/32-1/16 [.03125 .0625] in. (0.79-1.58 mm)
Seat
Width
Exhaust 1/16-3/32 [.0625-.09375] in. (1.58-2.38 mm)
Production
Intake .0010-.0027 (0.025-0.069)
Stem
Production
Exhaust .0012-.0029 (0.0304-0.0736)
Clearance
Service
Intake .003 (0.07) .0037 (0.09)
Service
Exhaust .004 (0.10) .0049 (0.12)
Stem Diameter
Intake .372 (9.45)
Stem
Diameter
Exhaust .372 (9.45)
Valve Margin (Intake and Exhaust) .0312 (0.79)
Valve Lash (Intake and Exhaust) Fixed Lash
VALVE SPRING
MODEL 454 MAG / 502 MAG / 8.2L
Free Length 2.15 (54.6)
Closed at 1.88 in.
(47.8 mm)
110 Lbs. (489 N)
Valve
1
Pressure
Closed at 1.80 in.
(45.7 mm)
Does Not Apply
Spring
1
Pressure
Open at 1.34 in.
(35.1 mm)
316 Lbs. (1406 N)
Open at 1.40 in.
(35.6 mm)
Does Not Apply
Installed Height 1.88 (47.7)
Damper or
Free Length 1.86 (47.2)
Damper
Shield
Approximate Number Of
Coils
4
Damper or
Damper
Shield
Valve Spring Fit in Damper
Shield
Does Not Apply
1
454/502/8.2L Models Only-Test spring pressure with inner and outer spring assembled.
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Index

Mercury MerCruiser MCM 502 Mag MPI Specifications

General

Brand	Mercury
Model	MerCruiser MCM 502 Mag MPI
Category	Engine
Language	English