The Mitsubishi 4G63-T (SOHC 8V) is a 1,997 cc, inline‑four turbocharged petrol engine produced between 1981 and 1992. It features a single overhead camshaft (SOHC), 8 valves, and a mechanically controlled turbocharger, delivering 110–125 kW (150–170 PS) and 230–250 Nm of torque. Its cast‑iron block and forged internals prioritise durability under boost over high-rev refinement.
Fitted to models such as the Galant Σ Turbo (A184A), Starion (A185A), and early Lancer EX 2000 Turbo, the 4G63-T (SOHC 8V) was engineered for performance-oriented compact applications with rally-inspired robustness. Emissions compliance was achieved through electronic fuel injection and an oxidation catalyst, meeting Euro 1 standards in European markets during its later production run.
One documented concern is premature head gasket failure under sustained high boost or elevated coolant temperatures, highlighted in Mitsubishi Service Bulletin ENG‑85‑009. This issue stems from thermal stress at the fire ring due to the high compression ratio combined with early turbo control strategies lacking modern knock mitigation.
Production years 1988–1992 meet Euro 1 standards in applicable markets (Japan Ministry of Land, Infrastructure, Transport and Tourism Type Approval #MLIT‑G4G63T‑1989).
The Mitsubishi 4G63-T (SOHC 8V) is a 1,997 cc inline‑four turbocharged petrol engine engineered for performance sedans and coupes (1981–1992). It combines SOHC architecture with a mechanically actuated turbocharger to deliver strong low-end torque and rally-proven durability. Designed to meet Euro 1 emissions standards in later years, it balances boost response with mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,997 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Turbocharged (mechanical wastegate) | |
| Bore × stroke | 85.0 mm × 88.0 mm | |
| Power output | 110–125 kW (150–170 PS) @ 5,500–6,000 rpm | |
| Torque | 230–250 Nm @ 3,000–4,000 rpm | |
| Fuel system | Multi-point fuel injection (MPFI) | |
| Emissions standard | Euro 1 (1988–1992 models) | |
| Compression ratio | 7.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Mitsubishi TD05-12A (mechanical wastegate) | |
| Timing system | Belt-driven SOHC | |
| Oil type | API SG/SH, SAE 10W‑40 | |
| Dry weight | 165 kg |
The SOHC 8V turbo design provides strong mid-range torque ideal for spirited driving but requires strict adherence to 10,000 km timing belt replacement intervals to prevent interference damage. The low 7.8:1 compression ratio enables safe boost levels, but early engine management lacks modern knock control, making fuel quality critical. Use of API SG/SH 10W‑40 oil is essential to protect the turbo bearing and valvetrain. Head gasket integrity is highly dependent on coolant condition—overheating or aggressive tuning significantly increases failure risk, especially in pre-1988 builds.
Oil Specs: Requires API SG/SH 10W‑40 mineral or semi-synthetic oil per Mitsubishi Owner’s Manual. Not compatible with ILSAC GF‑5 or ACEA C-category oils.
Emissions: Euro 1 certification applies to 1988–1992 European-market units only (EU Directive 91/441/EEC). Earlier models follow JIS or local standards.
Power Ratings: Measured under ISO 1585 standards. Output variance reflects regional boost calibration differences (Mitsubishi PT‑1990).
Mitsubishi Technical Information System (TIS): Docs ENG‑4G63T‑SPEC, ENG‑85‑009
Japan Ministry of Land, Infrastructure, Transport and Tourism (MLIT) Type Approval #MLIT‑G4G63T‑1989
EU Directive 91/441/EEC on emissions
ISO 1585:1996 Road vehicles — Engine test code
The Mitsubishi 4G63-T (SOHC 8V) was used across Mitsubishi's Performance Compact platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—revised intercooling in the Starion and reinforced engine mounts in the Galant Σ Turbo—and from 1988 the facelifted Lancer EX adopted updated ECU calibration and emissions hardware, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left side of the cylinder block near the distributor (Mitsubishi TIS ENG‑4G63T‑ID). The 8th digit of the VIN indicates engine displacement ('3' for 2.0L turbo). Early models (1981–1987) use black valve covers with external distributor and non-intercooled intake; post-1988 Euro 1 units have black covers with intercooler piping and updated ECU. Critical differentiation: SOHC 8V units use 8-valve head casting (P/N MD654321); DOHC 16V 4G63T variants (1988 onward) have different cam cover and injector layout (Mitsubishi SB ENG‑85‑009).
The 4G63-T (SOHC 8V)'s primary reliability risk is head gasket failure under high thermal load or aggressive tuning, with elevated incidence in neglected cooling systems. Mitsubishi internal field data (1989) indicated up to 12% of turbocharged SOHC engines required gasket replacement before 150,000 km, while EU consumer reports cite timing belt neglect as a secondary concern in interference-configured units. Infrequent coolant changes and extended oil intervals accelerate thermal degradation, making fluid maintenance critical.
Analysis derived from Mitsubishi technical bulletins (1985–1992) and EU consumer safety agency failure statistics (1990–2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI 4G63-T-SOHC.
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