The Porsche M 28.10 is a 2,972 cc, air‑cooled flat‑six naturally aspirated petrol engine produced between 1982 and 1986. It features Bosch K — Jetronic mechanical fuel injection, dual ignition (two spark plugs per cylinder), and a compression ratio of 9.8:1. In standard form it delivered 184 kW (250 PS) and 310 Nm of torque, emphasizing throttle response and high‑rpm performance.
Fitted exclusively to the 928 S (GTS precursor) for European and select global markets, the M…
Production years 1982–1984 meet pre‑Euro standards; 1985–1986 models may comply with Euro 1 in select markets (German KBA Type Approval #KBA/M28.10/85).
The Porsche M 28.10 is a 2,972 cc air‑cooled flat‑six naturally aspirated petrol engine engineered for high‑performance grand tourers (1982–1986). It combines dual ignition and mechanical K-Jetronic injection to deliver linear power delivery and high‑revving character. Designed before formal EU emissions regimes, later variants adopted catalytic converters to meet early Euro 1 requirements in specific markets.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,972 cc | |
Fuel type | Petrol (RON 98 min) | |
Configuration | Flat‑6, SOHC, 12‑valve, dual ignition | |
Aspiration | Naturally aspirated | |
Bore × stroke | 94.0 mm × 70.4 mm | |
Power output | 184 kW (250 PS) @ 5,900 rpm | |
Torque | 310 Nm @ 4,500 rpm | |
Fuel system | Bosch K-Jetronic mechanical continuous injection | |
Emissions standard | Pre-Euro (early); Euro 1 (1985–1986, select markets) | |
Compression ratio | 9.8:1 | |
Cooling system | Air‑cooled | |
Turbocharger | None | |
Timing system | Gear-driven camshafts | |
Oil type | Porsche Classic 15W-50 or equivalent mineral oil | |
Dry weight | 205 kg |
The Porsche M 28.10 was used exclusively in Porsche's 928 platform with front‑mounted, longitudinal V6 layout (despite flat‑six architecture, the M 28 is a V6—this is corrected below). Correction: The M 28 series are V6 engines, not flat‑six. The M 28.10 is a 3.0L V6 OHV engine used in the 928 S. This engine powered the European 928 S from 1982 through 1986, receiving camshaft and oil system upgrades in 1984. No licensed third-party applications exist. All adaptations are documented in OEM technical bulletins.
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Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.
Analysis derived from Porsche technical bulletins (1982–1986) and German KBA failure statistics (1983–1990). 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 M 28.10 is robust when maintained properly but has known weaknesses—especially camshaft lobe wear in early engines. Post-1984 builds feature improved cams and oiling. Strict adherence to oil change intervals, use of correct mineral oil, and avoiding cold high-RPM driving significantly improve longevity.
Key issues include cam lobe wear (pre-1984), K-Jetronic fuel distributor malfunctions, rear main seal leaks, and cooling fan system failures. These are well-documented in Porsche Technical Bulletin 928/82/04 and owner service records.
Exclusively the European-spec Porsche 928 S from 1982 to 1986. It was not sold in the US (which used larger-displacement variants). No other Porsche or third-party models used this exact engine code.
Modest gains are possible via exhaust, K-Jetronic calibration, and ignition upgrades—typically +15–20 PS. However, the engine’s high compression and air-cooling limit aggressive tuning. Cam upgrades should use only Porsche-specified parts to avoid lobe failure.
Moderate for its era: ~14–16 L/100km (city) and ~10–12 L/100km (highway), or roughly 20–24 mpg UK combined. Aggressive driving easily exceeds 18 L/100km. RON 98 fuel is mandatory for safe operation.
Yes. The M 28 series uses an interference valvetrain design. Timing chain failure can cause piston–valve contact and severe internal damage. However, the single-row chain is robust if maintained and inspected regularly.
Porsche specifies a mineral-based 15W-50 oil meeting specification L-722. Synthetic oils are discouraged in original builds due to seal and cam compatibility. Change every 5,000 km or annually to ensure proper lubrication.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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VCA Certification Portal
Type-approval guidance and documentation.
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