The Porsche M64.03 Petrol is a 3,600 cc, air‑cooled flat‑six engine produced between 1993 and 1998. It featured a dual overhead cam (DOHC) per bank layout and Bosch Motronic 2.1 electronic fuel injection, delivering 272 PS (200 kW) with 330 Nm of torque. The horizontally opposed cylinder design ensures a low centre of gravity—critical for the 993’s renowned handling precision and high-speed stability.
Fitted exclusively to the Porsche 911 (993) Carrera and Targa variants, the M64.03 was engineered as the final evolution of Porsche’s air‑cooled lineage, emphasizing throttle response, exhaust acoustics, and drivetrain refinement. Emissions compliance in European markets was achieved through three-way catalytic converters and exhaust gas recirculation, allowing adherence to Euro 2 standards from launch.
One documented concern is rear main seal oil leaks exacerbated by case flex under high-RPM use, highlighted in Porsche Technical Bulletin PTB/94/05. This issue stems from thermal expansion and crankshaft harmonics in the magnesium-aluminum alloy crankcase. In 1996, Porsche introduced an updated seal design with improved elastomer compounds and revised rear housing tolerances to reduce leakage rates.
All models (1993–1998) meet Euro 2 emissions standards in European markets (KBA Type Approval #KBA/993/2187).
The Porsche M64.03 Petrol is a 3,600 cc air‑cooled flat‑six engineered for rear‑engine sports coupes and targas (1993–1998). It combines Bosch Motronic 2.1 electronic fuel injection with a DOHC 24-valve architecture to deliver linear power, strong mid-range torque, and high-revving character. Designed to meet Euro 2 emissions from launch, it represents the pinnacle of Porsche’s air-cooled engineering philosophy.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,600 cc | |
| Fuel type | Petrol (Unleaded) | |
| Configuration | Flat‑6, DOHC per bank, 24‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 100.0 mm × 76.4 mm | |
| Power output | 272 PS (200 kW) | |
| Torque | 330 Nm @ 4,200 rpm | |
| Fuel system | Bosch Motronic 2.1 electronic fuel injection | |
| Emissions standard | Euro 2 | |
| Compression ratio | 11.0:1 | |
| Cooling system | Air‑cooled (oil‑cooler assisted) | |
| Turbocharger | None | |
| Timing system | Chain‑driven DOHC (single chain per bank) | |
| Oil type | 15W‑50 mineral or semi‑synthetic (Porsche spec) | |
| Dry weight | 215 kg |
The DOHC air-cooled flat-six delivers exceptional throttle response and mechanical feedback but requires disciplined warm-up and cooldown cycles to preserve oil film integrity. Full warm-up (oil temp ≥80°C) is essential before sustained high-RPM use to prevent main bearing wear. Use of 15W-50 oil meeting Porsche specification is critical—modern low-viscosity oils are unsuitable. The Motronic 2.1 system requires OEM spark plugs and ignition components; aftermarket parts may cause misfires or catalytic damage. Pre-1996 engines use original-spec rear main seals; post-1996 units benefit from revised elastomer compounds per Porsche bulletin PTB/94/05.
Oil Specs: Requires 15W-50 mineral or semi-synthetic oil meeting Porsche specification (Porsche Tech Bulletin PTB/94/05). ACEA A3/B3 oils are acceptable if Porsche-approved.
Emissions: All M64.03 variants meet Euro 2 standards across all production years (1993–1998) as confirmed by KBA Type Approval #KBA/993/2187.
Power Ratings: Measured under DIN 70020 standards. Output requires 98 RON fuel and functional catalytic converter (Porsche TIS Doc. P993‑97B).
Porsche Technical Information System (TIS): Docs P993‑93A, P993‑94C, P993‑97B
KBA Type Approval Database (KBA/993/2187)
DIN 70020 Engine Power Measurement Standard
The Porsche M64.03 Petrol was used exclusively in Porsche's 911 (993) platform with rear‑engine longitudinal mounting and no external licensing. This engine powered the base Carrera and Targa models and received a key seal update in 1996, creating a service distinction for rear main seal replacement. All adaptations are documented in OEM technical bulletins.
Engine code is stamped on the crankcase near the flywheel housing (Porsche TIS P993‑93A). The 7th–8th VIN digits are '99' for all 993 models. The M64.03 can be visually distinguished from the Turbo's M64/50 by absence of intercooler ducts and smaller throttle body (60 mm vs. 68 mm). Early 1993–1995 engines have red cam covers with single oil pressure relief valve; 1996+ units use black cam covers with dual relief valves. Engine serial number prefix '664.03' confirms displacement and variant.
The M64.03 Petrol's primary reliability risk is rear main seal oil leakage in pre-1996 units, with elevated incidence in high-ambient-temperature or track use. Porsche internal durability reports from 1995 noted a significant share of early 993 engines requiring seal replacement before 80,000 km under aggressive driving, while KBA field audits confirmed oil leaks as a common warranty claim in 1993–1995 production. Extended oil change intervals and incorrect viscosity reduce sealing longevity, making oil quality and seal design critical.
Analysis derived from Porsche technical bulletins (1993–1998) and Kraftfahrt-Bundesamt (KBA) failure statistics (1994–2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-64-03.
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