The Mitsubishi G15B is a 1,468 cc, inline‑four naturally aspirated petrol engine produced between 1983 and 1991. It features a single overhead camshaft (SOHC), 8 valves, and a carburettor or throttle-body fuel injection system depending on market and year. In standard form it delivered 55–63 kW (75–86 PS) with torque of 110–120 Nm, engineered for economical urban driving and basic reliability.
Fitted to entry-level models such as the Mirage (C10/C20), Lancer (CA), and Colt (C10), the G15B was designed as a cost-effective powerplant for emerging markets and compact city cars. Emissions compliance was achieved through basic exhaust gas recirculation (EGR) and oxidation catalysts in later models, allowing limited compliance with early Japanese and European pre-Euro 1 standards.
One documented concern is premature wear of the distributor drive gear due to marginal lubrication in high-ambient-temperature climates. This issue, referenced in Mitsubishi Technical Service Bulletin TSB-ENG-1987-03, can lead to ignition timing drift and misfire. From 1988 onward, Mitsubishi revised the gear material and oil feed path to improve durability under tropical operating conditions.
Production years 1983–1991 meet no formal EU emissions standard (pre-Euro 1); Japanese domestic models complied with 1983–1991 JIS emission regulations (Mitsubishi ETK Doc. ME-G15B-01).
The Mitsubishi G15B is a 1,468 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and sedans (1983–1991). It combines SOHC 8-valve architecture with carburettor or throttle-body injection to deliver basic urban performance and serviceability. Designed before formal Euro standards, it relies on rudimentary emissions controls and prioritizes mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,468 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 75.5 mm × 82.0 mm | |
| Power output | 55–63 kW (75–86 PS) @ 5,500 rpm | |
| Torque | 110–120 Nm @ 3,500 rpm | |
| Fuel system | Carburettor or throttle-body injection (TBI) | |
| Emissions standard | Pre-Euro (JIS 1983–1991 compliant) | |
| Compression ratio | 9.2:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt‑driven SOHC | |
| Oil type | API SF/SG, SAE 10W‑30 | |
| Dry weight | 92 kg |
The SOHC 8-valve design provides adequate low-RPM response for city driving but requires strict 10,000 km oil change intervals using API SF/SG 10W-30 oil to maintain camshaft and distributor drive lubrication. Extended intervals in hot climates can accelerate distributor gear wear, especially in pre-1988 engines. The timing belt must be replaced every 80,000 km or 4 years—failure in this interference engine causes catastrophic valve/piston contact. Post-1988 engines feature the revised distributor drive gear (P/N MD332211) per TSB-ENG-1987-03 and should be used in all replacements. Use only EN 228-compliant fuel to protect carburettor jets and TBI injectors.
Oil Specs: Requires API SF or SG specification (Mitsubishi Owner’s Manual 1986). ACEA A2 acceptable if SF unavailable.
Emissions: No Euro classification applies; Japanese models met JIS 1983–1991 standards (Mitsubishi ETK Doc. ME-G15B-01).
Power Ratings: Measured under JIS D 1001 standards. Output varies by fuel system and market (Mitsubishi PT-1990).
Mitsubishi Technical Information System (TIS): Docs ENG-G15B-A, ME-G15B-01
Mitsubishi Technical Service Bulletin TSB-ENG-1987-03
JIS D 1001: Japanese Industrial Standard for Engine Power Measurement
Mitsubishi Lightweight Engineering Report #MLER-02
The Mitsubishi G15B was used across Mitsubishi's C-platform with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Mirage and modified cooling in the Lancer—and from 1988 the distributor drive gear was revised, creating minor parts incompatibility. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front-right side of the block near the timing cover (Mitsubishi TIS ENG-G15B-B). The 7th VIN digit is '5' for 1.5L G-series engines. Visual identification: SOHC rocker cover with 4 bolts and single distributor mounted on block side. Critical differentiation from G13B: G15B has 1,468 cc displacement (vs. 1,298 cc) and larger bore. Pre-1988 distributor drive gears use P/N MD221100; post-1988 use MD332211 with hardened surface treatment.
The G15B's primary reliability risk is distributor drive gear wear in early builds, with elevated incidence in high-ambient-temperature climates or vehicles with delayed oil changes. Mitsubishi internal field data from 1988 indicated distributor faults in ~10% of pre-1988 engines before 100,000 km, while period service records show low emissions failure rates due to simple oxidation catalyst design. Thermal stress and oil degradation make lubrication quality and timing belt discipline critical.
Analysis derived from Mitsubishi technical bulletins (1986–1990) and Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT) service records (1985–1992). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MITSUBISHI G15B.
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