The Porsche M 55.01 is a 2,687 cc, dual — overhead — cam flat‑six petrol engine produced between 2005 and 2008. It featured Bosch Motronic ME7.8.1 sequential fuel injection, an aluminum block with Nikasil — coated cylinders, and a dry‑sump lubrication system. In standard form it delivered 180 kW (245 PS) and 290 Nm of torque, offering increased displacement and refinement over the previous M 48 architecture while retaining mid — engine balance.
Fitted exclusively to the 98…
Production years 2005–2008 meet Euro 4 standards (TÜV Certificate TÜV/05/M55/11).
The Porsche M 55.01 is a 2,687 cc flat‑six petrol engine engineered for the mid-mounted 987 Boxster and Cayman (2005–2008). It combines DOHC architecture with sequential fuel injection and dry-sump lubrication for stable oil supply during high-g cornering. Designed to meet Euro 4 emissions standards, it integrates catalytic converters and secondary air injection for regulatory compliance while improving on prior-generation torque and smoothness.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,687 cc | |
Fuel type | Petrol (RON 95 min, RON 98 recommended) | |
Configuration | Flat‑6, DOHC, 24‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 89.0 mm × 72.0 mm | |
Power output | 180 kW (245 PS) @ 6,400 rpm | |
Torque | 290 Nm @ 4,750 rpm | |
Fuel system | Bosch Motronic ME7.8.1 sequential injection | |
Emissions standard | Euro 4 | |
Compression ratio | 10.9:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 158 kg |
The Porsche M 55.01 was used exclusively in Porsche's 987 platform with mid‑mounted, longitudinal flat-six mounting and no external licensing. This engine received platform-specific tuning—revised oil galleries in the 2006 Boxster S and updated exhaust manifolds in 2007 Cayman—and from 2008 was succeeded by the M 97.22 2.9L with VarioCam Plus and higher output, creating clear generational boundaries. All adaptations are documented in OEM technical bulletins.
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The M 55.01's primary reliability risk is rear main seal (RMS) leakage due to installation sensitivity and PCV system degradation, with elevated incidence in high-mileage or track-used vehicles. Porsche internal data (2006) noted a 9% RMS replacement rate in 987 S models before 120,000 km, while TÜV Germany MOT records show elevated oil consumption in engines with neglected PCV systems. Extended high-load operation without maintenance accelerates seal stress, making RMS protocol and oil quality critical.
Analysis derived from Porsche technical bulletins (2005–2008) and TÜV Germany failure statistics (2007–2017). 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 55.01 improves on earlier flat-six designs with dual-lip RMS and better torque, but still shares the single-row IMS bearing weakness. With RON 98 fuel, regular oil changes, and PCV maintenance, well-maintained examples can exceed 160,000 km reliably. Early attention to RMS torque and coolant integrity is essential.
Top issues include RMS leaks (often from improper installation), IMS bearing wear, Nikasil bore scoring from coolant leaks, and cam sensor failure. These are documented in Porsche Technical Bulletin PTB/987/05 and TIS 987-series manuals.
Exclusively fitted to the 2005–2008 Porsche Boxster S (987) and 2006–2008 Cayman S (987) as the 2.7L model. No other Porsche or external brands used this engine code.
Modest gains are possible. ECU remaps yield +10–15 kW. Forced induction is uncommon due to Nikasil bore sensitivity and non-forged internals. Most owners prioritize reliability over significant tuning.
Efficient for a flat-six: ~11.4 L/100km (24.8 mpg UK) combined, rising to ~14.0 L/100km in city and dropping to ~9.0 L/100km on highway. Aggressive driving can exceed 16 L/100km.
Yes. The M 55.01 is an interference engine with tight piston-to-valve clearance. Timing chain failure or jump can result in catastrophic internal damage. However, the chain system is generally robust with low reported failure rates.
Porsche specifies 5W‑40 synthetic oil meeting ACEA C3 and API SM (e.g., Porsche C3 or Mobil 1 ESP 5W-40). Oil must be changed every 10,000 km to protect the IMS bearing and catalytic converters. Extended intervals increase wear and deposit risk.
Comprehensive technical documentation and regulatory references
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UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
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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.
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