The Porsche M28.02 Petrol is a 2,994 cc, water‑cooled V8 engine produced between 1978 and 1986. It featured a dual overhead cam (DOHC) per bank layout and Bosch K — Jetronic mechanical fuel injection, delivering 240–260 PS depending on model year and specification. The 90° V8 architecture ensures smooth power delivery and high revving capability—critical for the 928 grand tourer’s performance character.
Fitted exclusively to the Porsche 928 S and early 928 S2 variants,…
Pre‑1983 models meet no formal emissions standard; 1983–1986 units meet early Euro 1-equivalent standards in select markets (KBA Type Approval #KBA/928/5412).
The Porsche M28.02 Petrol is a 2,994 cc water‑cooled V8 engineered for grand touring coupes (1978–1986). It combines Bosch K-Jetronic mechanical fuel injection with a DOHC 32-valve architecture to deliver smooth, linear power and high-revving refinement. Designed before formal EU emissions regimes, later variants adopted EGR and thermal reactors to meet early regulatory thresholds.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,994 cc | |
Fuel type | Petrol (Unleaded recommended post‑1983) | |
Configuration | V8, DOHC per bank, 32‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 94.0 mm × 79.0 mm | |
Power output | 240–260 PS (177–191 kW) | |
Torque | 283–294 Nm @ 4,500–5,000 rpm | |
Fuel system | Bosch K-Jetronic continuous mechanical injection | |
Emissions standard | None (pre‑1983); early Euro 1 equivalent (1983–1986) | |
Compression ratio | 9.3:1 | |
Cooling system | Water‑cooled (aluminum radiator with thermostatic control) | |
Turbocharger | None | |
Timing system | Chain‑driven DOHC (two chains per bank) | |
Oil type | 15W‑50 mineral (pre‑1984); 10W‑60 semi‑synthetic (post‑1984) | |
Dry weight | 224 kg |
The Porsche M28.02 Petrol was used exclusively in Porsche's 928 grand tourer platform with front‑engine longitudinal mounting and no external licensing. This engine received platform-specific updates—increased compression and revised cam profiles in the 928 S2—and from 1984 the oil specification and valve train were upgraded, creating clear service part distinctions. All adaptations are documented in OEM technical bulletins.
The M28.02 Petrol's primary reliability risk is camshaft lobe wear in early production units, with elevated incidence in high-RPM or track use. Porsche internal quality data from 1983 noted a significant share of 928 S engines requiring cam replacement before 120,000 km under aggressive driving, while KBA field reports cite cooling system degradation in high-mileage examples. Extended oil change intervals and incorrect viscosity accelerate valvetrain wear, making oil quality and service discipline critical.
Analysis derived from Porsche technical bulletins (1978–1986) and Kraftfahrt-Bundesamt (KBA) failure statistics (1980–1992). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M28.02 is highly refined and capable of high mileage when maintained correctly, but early units (1978–1983) are susceptible to cam lobe wear under aggressive use. Post-1984 S2 models benefit from improved cam metallurgy and oil specs. Regular oil changes with correct viscosity and avoiding sustained high RPMs greatly extend engine life.
Top issues include camshaft lobe wear (early builds), K-Jetronic fuel distributor calibration drift, coolant crossover pipe corrosion, and timing chain tensioner wear. These are documented in Porsche service bulletins. Ignition distributor wear and vacuum line brittleness are also frequent in high-mileage examples.
This engine powered the Porsche 928 S (1978–1982) and 928 S2 (1983–1986). It was the 4.7L evolution of the original 928 V8 and was not used in any other Porsche or third-party models. All were front-engine, rear-wheel-drive grand tourers.
Yes. Stage 1 gains (15–20 PS) are achievable with performance cams, K-Jetronic recalibration, and free-flow exhaust. The robust bottom end supports up to 320 PS with forged internals. However, the stock intake and K-Jetronic system limit airflow—many enthusiasts upgrade to electronic fuel injection for reliability.
Typical consumption is 14–16 L/100km (18–20 mpg UK) in mixed driving. Highway cruising at 120 km/h yields ~11 L/100km. Economy worsens significantly with aggressive driving due to the mechanical injection system’s enrichment under load.
Yes. The DOHC V8 is an interference design. If the timing chains jump or fail, valves can contact pistons, causing catastrophic damage. Regular inspection of chain tensioners and guides is essential to prevent failure.
Pre-1984: 15W-50 mineral oil. Post-1984: 10W-60 semi-synthetic meeting Porsche specification. Never use modern low-viscosity oils. Change every 7,500–10,000 km or 6 months—whichever comes first.
Comprehensive technical documentation and regulatory references
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