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, the M28.02 was engineered for refined high-speed cruising with emphasis on torque bandwidth and acoustic balance. Emissions compliance in European markets was achieved through exhaust gas recirculation (EGR) and thermal reactors, allowing adherence to early Euro 1-equivalent standards from 1983 onward.
One documented concern is camshaft lobe wear due to inadequate oil film under high thermal load, highlighted in Porsche Technical Bulletin PTB/82/06. This issue stems from the initial cam profile design and marginal oil pressure at elevated temperatures in early production units. In 1984, Porsche revised cam metallurgy and introduced stiffer valve springs to mitigate wear during extended high-RPM operation.
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 DOHC V8 provides refined high-RPM performance but requires strict adherence to oil change intervals and quality to prevent cam lobe wear. Use of 10W-60 semi-synthetic oil post-1984 is critical due to improved high-temperature film strength. Cold starts below 5°C should be followed by 5–10 minutes of gentle driving. The K-Jetronic system is sensitive to fuel pressure stability—only OEM-spec pumps and accumulators ensure consistent mixture control. Valve clearance must be inspected every 40,000 km; hydraulic lifters are not used. Early cam wear manifests as ticking or loss of high-end power.
Oil Specs: Requires 15W-50 mineral oil for pre-1984 engines; 10W-60 semi-synthetic (Porsche spec) post-1984 per Tech Bulletin PTB/82/06.
Emissions: No formal emissions standard applies to pre-1983 models. 1983–1986 units meet early Euro 1-equivalent thresholds in Germany (KBA Type Approval #KBA/928/5412).
Power Ratings: Measured under DIN 70020 standards. 260 PS S2 output requires 98 RON fuel and optimal K-Jetronic calibration (Porsche TIS Doc. P928‑85B).
Porsche Technical Information System (TIS): Docs P928‑78A, P928‑80C, P928‑85B
KBA Type Approval Database (KBA/928/5412)
DIN 70020 Engine Power Measurement Standard
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.
Engine code is stamped on the left cylinder bank near the rear cam cover (Porsche TIS P928‑78A). The 7th–8th VIN digits are '92' for all 928 models; the engine displacement is indicated by the '28' prefix in internal codes. Early M28.02 units (1978–1983) have silver cam covers and mechanical tach drive; S2 models (1984+) feature black cam covers and electronic ignition trigger. Camshaft gear timing marks differ between early and late variants—verify with TIS diagrams before reassembly.
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.
Find answers to most commonly asked questions about PORSCHE M-28-02.
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