Mercury MerCruiser MCM 7.4L MPI User Manual

454 CID (7.4L) / 502 CID (8.2L)
SERVICE MANUAL NUMBER 23
Page 3A-15
90-861326--1 MARCH 1999
7.4L MPI (L-29) Engine Specifications (Continued)
VALVE SYSTEM
MODEL 7.4L
Lifter Hydraulic Roller
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 .0300-.0600 (0.7620-1.5240)
Seat
Width
Exhaust .0600-.0950 (1.5240-2.4130)
Production
Intake .0010-.0029 (0.0254-0.0737)
Stem
Production
Exhaust .0012-.0031 (0.0300-0.0787)
Clearance
Service
Intake .0037 (0.0939)
Service
Exhaust .0049 (0.1244)
Valve Lash (Intake and Exhaust) Net Lash
CYLINDER HEAD
MODEL 7.4L
Gasket Surface Flatness
.004 (0.1016) Overall Maximum .003
(0.076) within a 6 in. (152 mm) Span
MODEL 7.4L
Lobe Lift ± 020 (0 051)
Exhaust .284 (7.214)
Lobe
Lift
±
.
020
(0
.
051)
Intake .282 (7.163)
Duration at 050 In (1 27mm) Cam Lift
Exhaust 209°
Duration
at
.
050
In
.
(1
.
27mm)
Cam
Lift
Intake 209°
Journal Diameter
1.9482-1.9492
(49.485-49.509)
Journal Out Of Round .001 (0.025) Max
Camshaft Runout .002 (0.051) Max
Timing Chain Deflection
.375 (9.5) from taut position
[Total .75 (19)]
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Index

Mercury MerCruiser MCM 7.4L MPI Specifications

General

Engine Type	V8
Bore	4.25 in (108 mm)
Compression Ratio	8.6:1
Ignition System	Electronic Ignition
Alternator	65 Amp
Displacement	7.4L (454 cu in)
Fuel System	Multi-Port Fuel Injection (MPI)
Horsepower	310 HP
Torque	450 lb-ft
Cooling System	Closed Cooling
Fuel Requirement	87 octane (minimum)
Stroke	4.00 in (101.6 mm)