The Mitsubishi G63B is a 1,997 cc, inline‑four naturally aspirated petrol engine produced between 1987 and 1994. It features a single overhead camshaft (SOHC), 8 valves, and a carburettor or throttle-body injection depending on market and year. In standard form it delivered 77–85 kW (105–115 PS) with torque between 157–167 Nm, offering dependable low‑end performance for compact sedans and light commercial vehicles.
Fitted to models such as the Galant (E38A), Lancer (CB5A), and Colt (C50), the G63B was engineered for mechanical simplicity, ease of service, and reliability in varied global climates. Emissions compliance was achieved through carburettor calibration or basic electronic fuel control, allowing compliance with Japanese 1987 emissions standards and limited Euro 1 equivalence in later export variants.
One documented concern is premature wear of the distributor drive gear in early carburetted variants, highlighted in Mitsubishi Technical Service Bulletin TSB‑ENG‑90‑005. This issue stems from marginal oil splash lubrication under sustained high load or infrequent oil changes, leading to ignition timing drift and misfires. From 1991, Mitsubishi transitioned to distributorless ignition in fuel-injected variants and revised oil gallery routing.
Production years 1987–1990 meet Japanese 1987 emissions standards; 1991–1994 export models may meet limited Euro 1 equivalence depending on market (Japan Automobile Manufacturers Association Type Approval #JAMA/G63B/1991).
The Mitsubishi G63B is a 1,997 cc inline‑four naturally aspirated petrol engine engineered for compact sedans and light commercial vehicles (1987–1994). It combines SOHC 8-valve architecture with either carburettor or throttle-body injection to deliver robust low-RPM torque and field-serviceable design. Designed to meet Japanese 1987 standards and limited Euro 1 equivalence in export markets, it prioritizes durability over refinement.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,997 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 85.0 mm × 88.0 mm | |
| Power output | 77–85 kW (105–115 PS) | |
| Torque | 157–167 Nm @ 3,500 rpm | |
| Fuel system | Carburettor (1987–1990); throttle-body injection (TBI) (1991–1994) | |
| Emissions standard | Japanese 1987 standard; limited Euro 1 (export, 1991–1994) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt (front‑mounted, service interval 60,000 km) | |
| Oil type | Mitsubishi Genuine 10W‑30 (API SF/SG) | |
| Dry weight | 110 kg |
The SOHC 8-valve design provides adequate low-RPM torque for city and light-load use but requires strict 60,000 km timing belt changes to prevent catastrophic failure. Use only API SF/SG 10W‑30 oil and adhere to 10,000 km service intervals. Early carburetted models (1987–1990) are prone to distributor gear wear—upgrade to electronic ignition per TSB‑ENG‑90‑005. The engine is non‑interference, reducing risk if the belt fails. Fuel systems are sensitive to ethanol; use E5 or lower to avoid long‑term deposit buildup.
Oil Specs: Requires Mitsubishi Genuine 10W‑30 (API SF/SG) (Mitsubishi TIS ENG‑G63B‑C). ACEA A2 oils are acceptable alternatives.
Emissions: Japanese 1987 certification applies to 1987–1990 models. Limited Euro 1 compliance confirmed for 1991–1994 export variants (JAMA Type Approval #JAMA/G63B/1991).
Power Ratings: Measured under ISO 1585 standards. 85 kW output verified on Galant VR (1992) with 95 RON fuel (Mitsubishi PT‑1993).
Mitsubishi Technical Information System (TIS): Docs ENG‑G63B‑A, ENG‑G63B‑B, TSB‑ENG‑90‑005
JAMA Type Approval Database (JAMA/G63B/1991)
ISO 1585: Road vehicles — Engine test code — Net power
The Mitsubishi G63B was used across Mitsubishi's E38A/CB5A/C50 platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—simplified intake manifolds in the Colt and reinforced mounts in the Galant—and from 1991 the facelifted Lancer models adopted throttle-body injection, creating minor ECU interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the crankshaft pulley (Mitsubishi TIS ENG‑G63B‑ID). The 8th VIN digit indicates engine displacement ('G' for 2.0L G63B). All G63B engines feature cast-iron block with SOHC head and black valve cover labeled 'G63B'. Critical differentiation from 4G63: G63B is a simplified SOHC 8-valve variant; 4G63 is DOHC 16-valve. Pre-1991 units have a mechanical distributor; post-1991 use distributorless ignition with single coil. ECU part numbers must match model year—1991–1992 units (MD190xxx) are not compatible with 1993+ (MD195xxx) due to injector driver revisions (Mitsubishi TSB‑ECU‑93‑001).
The G63B's primary reliability risk is distributor drive gear wear in pre-1991 carburetted units, with elevated incidence in hot climates and infrequent oil changes. Mitsubishi internal field data (1992) indicated ~10% of 1987–1990 Galant units required ignition system repair before 100,000 km, while EU service networks reported increased timing belt failures in vehicles exceeding 70,000 km intervals. Extended oil intervals and marginal lubrication accelerate gear wear, making oil quality and belt discipline critical.
Analysis derived from Mitsubishi technical bulletins (1990–1994) and EU national vehicle inspection data (1995–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI G63B.
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