Mercury MerCruiser MCM 454 Mag MPI Service Manual page 214

454 CID (7.4L) / 502 CID (8.2L)
454 Mag / 502 Mag / 8.2L (Except 7.4L MPI L-29) Engine Specifications
(Continued)
VALVE SYSTEM
Stem
Clearance
Valve Margin (Intake and Exhaust)
VALVE SPRING
Valve
Spring
Damper or
Damper
Shield
Damper or
Damper
Shield
1
454/502/8.2L Models Only-Test spring pressure with inner and outer spring assembled.
Index
Page 3A-10
Downloaded from https://needmanual.com/
MODEL
Lifter
Rocker Arm Ratio
Face Angle (Intake & Exhaust)
Seat Angle (Intake & Exhaust)
Seat Runout (Intake & Exhaust)
Seat Width Seat Width
Production Production
Service Service
Stem Diameter Stem Diameter
Valve Lash (Intake and Exhaust)
MODEL
Free Length
Closed at 1.88 in.
Closed at 1.80 in.
Pressure Pressure
1
1
Open at 1.34 in.
Open at 1.40 in.
Installed Height
Free Length
Approximate Number Of
Coils
Valve Spring Fit in Damper
Shield
454 MAG
Intake 1/32-1/16 [.03125 .0625] in. (0.79-1.58 mm)
Exhaust 1/16-3/32 [.0625-.09375] in. (1.58-2.38 mm)
Intake .0010-.0027 (0.025-0.069)
Exhaust .0012-.0029 (0.0304-0.0736)
Intake .003 (0.07)
Exhaust .004 (0.10)
Intake
Exhaust
454 MAG / 502 MAG / 8.2L
(47.8 mm)
(45.7 mm)
(35.1 mm)
(35.6 mm)
SERVICE MANUAL NUMBER 23
502 MAG / 8.2L
Hydraulic
1.70 to 1
45
46
.002(0.05) Max
.0037 (0.09)
.0049 (0.12)
.372 (9.45)
.372 (9.45)
.0312 (0.79)
Fixed Lash
2.15 (54.6)
110 Lbs. (489 N)
Does Not Apply
316 Lbs. (1406 N)
Does Not Apply
1.88 (47.7)
1.86 (47.2)
4
Does Not Apply
90-861326--1 MARCH 1999