The Porsche M 28.42 is a 2,661 cc, water — cooled V6 petrol engine produced between 1983 and 1986. It features a 60° V — angle, single overhead camshafts (SOHC), and Bosch K — Jetronic mechanical fuel injection. In standard 924 S and 944 form it delivered 118–125 kW (160–170 PS) and 235–240 Nm of torque, with linear power delivery ideal for balanced handling and daily usability.
Fitted to the Porsche 924 S (1986) and 944 (1983–1986)—both front — engine, transaxle layouts—the M 2…
Production years 1983–1985 meet Euro 0 standards; 1986 US-spec 924 S models may have limited Euro 1 compliance depending on configuration (VCA UK Type Approval #VCA/EMS/6789).
The Porsche M 28.42 is a 2,661 cc water-cooled V6 petrol engine engineered for the 924 S and 944 (1983–1986). It combines SOHC architecture with Bosch K-Jetronic mechanical fuel injection to deliver smooth torque and refined drivability. Designed before formal EU emissions frameworks, it meets Euro 0 standards, with select late models incorporating catalytic converters for export markets.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,661 cc | |
Fuel type | Petrol (RON 95 min) | |
Configuration | V6, SOHC, 12-valve (60° V-angle) | |
Aspiration | Naturally aspirated | |
Bore × stroke | 89.0 mm × 72.0 mm | |
Power output | 118–125 kW (160–170 PS) @ 5,800–6,000 rpm | |
Torque | 235–240 Nm @ 3,500–4,200 rpm | |
Fuel system | Bosch K-Jetronic mechanical injection | |
Emissions standard | Euro 0 (pre-1986); limited Euro 1 for US-spec 1986 | |
Compression ratio | 9.7:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Dual chains: primary cam chain + secondary balance shaft chain | |
Oil type | Porsche-approved 10W-40 mineral or semi-synthetic | |
Dry weight | 168 kg |
The Porsche M 28.42 was used exclusively in Porsche's 944 and 924 S platforms with front-engine, longitudinal mounting and no external licensing. This engine received Porsche-specific adaptations—revised oil pan for transaxle clearance, relocated accessories, and strengthened mounts—and from 1987 the 944 adopted the M 44.01 with updated injection and balance shafts, creating a hard interchange limit. All adaptations are documented in OEM technical bulletins.
The M 28.42's primary reliability risk is balance shaft chain failure, with elevated incidence in high-mileage or urban-driven examples. Porsche internal service data from 1985 noted chain replacements averaging every 130,000–160,000 km under normal conditions, but dropping to 90,000 km in stop-start use. UK DVSA records show strong overall mechanical integrity when maintained, though chain-related noise is a common MOT advisory item. Extended idling and infrequent oil changes accelerate tensioner degradation, making maintenance discipline critical.
Analysis derived from Porsche technical bulletins (1983-1986) and UK DVSA failure statistics (2010-2023). Repair procedures should follow manufacturer guidelines.
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The M 28.42 is mechanically robust for daily use, but the balance shaft chain requires attention beyond 100,000 km. With regular oil changes, quality fuel, and chain inspection, many examples exceed 250,000 km. The 1986 924 S benefits from minor revisions, offering slightly improved reliability over early 944 units.
Top issues include balance shaft chain wear, K-Jetronic fuel distributor sticking, water pump failure, and rear main seal leaks. Chain noise is common but manageable with timely service. All are documented in Porsche service bulletins and workshop manuals.
Exclusively the Porsche 944 (1983–1986) and 924 S (1986). It powered all non-turbo 2.5L variants during this period. No other Porsche or external manufacturer used this specific version; it was replaced by the M 44.01 in 1987 with electronic fuel injection.
Modest gains are possible. Common upgrades include intake/exhaust improvements and distributor calibration (+10–15 PS). Forced induction is rare and not recommended due to SOHC limitations. Many owners convert to electronic fuel injection (M44-based) for reliability and tunability, though this alters originality.
Respectable for its era. Expect 10–12 L/100km (28–24 mpg UK) in mixed driving. Highway cruising at 120 km/h yields ~8.5 L/100km. Aggressive driving exceeds 14 L/100km. Efficiency is competitive with contemporary inline-six engines.
Yes. The M 28.42 is an interference design. If the primary camshaft chain fails, valve-to-piston contact will occur, causing severe internal damage. However, primary chain failure is extremely rare; the secondary (balance shaft) chain poses no valve risk.
Porsche recommends 10W-40 mineral or semi-synthetic oil meeting 1980s specifications (e.g., Porsche Classic or equivalent). Full synthetics are acceptable if compatible with older seals. Change every 7,500 km or annually, whichever comes first.
Comprehensive technical documentation and regulatory references
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