Mitsubishi 4G61, 4G63, 4G64 factory manual: 1992 edition (OEM)

• A 108-page PDF of Mitsubishi’s 1992 engine overhaul section for 4G61 DOHC, 4G63 SOHC/DOHC, and 4G64 SOHC, including naturally aspirated and turbocharged 4G63 DOHC configurations.
• Separate SOHC and DOHC timing-belt procedures cover belt inspection, tensioner setup, and balance-shaft timing, with distinctions for engines with and without silent shafts.
• Cylinder-head repair extends to valve-seat reconditioning and replacement, valve-guide replacement, camshaft and rocker-arm inspection, and lash-adjuster air bleeding and leak-down testing.
• Bottom-end overhaul includes piston-pin removal and installation, piston-ring inspection, cylinder boring, and plastic-gauge checks of connecting-rod and crankshaft main-bearing oil clearances.
• Front-case and lubrication service covers oil-pump gear inspection, silent-shaft bearing replacement, oil-pan resealing, and oil-cooler bypass-valve testing.
• Fuel and emission-control checks address injectors, EGR valve operation, throttle-position sensors, and the separate idle-speed-control and idle-air-control motor arrangements.
• Turbocharger disassembly and reassembly procedures include turbine housing, compressor cover, and wheel-assembly inspection, plus wastegate actuator operation testing.

Engine Systems and Application Details

The engine sections distinguish GALANT/EXPO and TRUCK SOHC fuel-system layouts. Throttle-body coverage separates the EXPO unit from the GALANT/TRUCK SOHC type and the DOHC stepper-motor arrangement. Sensor installation notes also identify ECLIPSE and MIRAGE applications.

Turbo injector identification is divided between the listed GALANT/ECLIPSE manual-transmission and ECLIPSE automatic-transmission applications. Mounting-bracket illustrations separate rear-wheel-drive/four-wheel-drive installations from front-wheel-drive/all-wheel-drive layouts. The crankshaft section provides separate flywheel and drive-plate arrangements.

Intake and exhaust manifold sections include water-pump removal and installation, thermostat housings, coolant-temperature sensors and gauge senders, and turbocharger oil and water pipes. Generator and ignition-system sections cover accessory-drive hardware, distributor installation for SOHC engines, and crankshaft-position-sensor installation for DOHC engines.

Inspection Specifications and Reassembly References

The specification pages separate standard dimensions from service limits for cylinder-head flatness, valve-stem-to-guide clearance, cylinder bores, piston fit, and crankshaft bearings. Torque tables cover individual assemblies, including cylinder-head fasteners. Sealant references and electrical test values accompany the mechanical data.

Reassembly notes identify camshafts, rocker arms, bearing caps, and head gaskets by their factory markings. Machining references include oversize valve-seat and guide-bore dimensions and the combined cylinder-head/block resurfacing allowance.

Special-tool references include MD998440 for lash-adjuster leak-down testing and MD998727 for oil-pan removal. The piston-pin procedure uses MIT216941, which the tool table cross-references to MD998780.

Technical Drawings and Service Cautions

Illustrations include Engine Sectional View—SOHC and Engine Sectional View—DOHC, plus Engine Lubrication System—DOHC-Turbo for tracing the lubricating-oil layout and cooler connections. Exploded views for Throttle Body—DOHC and Crankshaft, Flywheel and Drive Plate identify component relationships and fastener locations for repair work.

The DOHC camshaft service notes warn that locking a sprocket with a holding tool can damage it. The turbocharger test section also warns that excessive test pressure can damage the wastegate actuator diaphragm.

Always verify that your lifting equipment and engine stands meet the necessary load ratings before starting a major block teardown or assembly procedure.

Scope of This Engine Overhaul Manual

This is an engine overhaul reference, not a complete vehicle repair manual. Its electrical material consists of component checks and terminal illustrations; it does not provide full vehicle wiring diagrams, ECU fault-code troubleshooting, or vehicle-specific engine removal procedures.