The Porsche 901.08 is a 2,195 cc, flat‑six (horizontally opposed) naturally aspirated petrol engine produced between 1966 and 1967. It powered the Porsche 911S, delivering enhanced performance over earlier units through higher compression and revised valve timing. Featuring an air‑cooled design, dual overhead camshafts (DOHC), and Bosch mechanical fuel injection, it generated 160 PS (118 kW) at 6,600 rpm and 186 Nm of torque. This engine marked Porsche's first use o…
The 901.08 predates EU emissions regulations and was not type-approved under modern frameworks (VCA/EU).
The Porsche 901.08 is a 2,195 cc flat‑six air‑cooled petrol engine engineered for performance coupés (1966–1967). It combines DOHC valvetrain architecture with Bosch mechanical fuel injection to deliver high-revving character and motorsport-derived responsiveness. Designed before emissions regulation, it prioritizes mechanical precision and power density.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,195 cc | |
Fuel type | Petrol (Gasoline) | |
Configuration | Flat‑6 (horizontally opposed), DOHC, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 84.0 mm × 66.0 mm | |
Power output | 118 kW (160 PS) @ 6,600 rpm | |
Torque | 186 Nm @ 5,200 rpm | |
Fuel system | Bosch mechanical fuel injection (PI system) | |
Emissions standard | Not applicable (pre-regulation era) | |
Compression ratio | 9.8:1 | |
Cooling system | Air‑cooled (fan‑driven) | |
Turbocharger | None | |
Timing system | Gear-driven dual overhead camshafts | |
Oil type | SAE 20W-50 mineral oil (API SC/SD) | |
Dry weight | 182 kg |
The Porsche 901.08 was used exclusively in the Porsche 911S with rear‑engine, longitudinal mounting. This high‑performance variant was developed for homologation and motorsport support, featuring unique cylinder heads, camshafts, and injection calibration. No cross‑manufacturer or platform sharing occurred. All revisions are documented in Porsche engineering bulletins.
The 901.08's primary reliability challenges are valve train wear under improper clearance settings and fuel system sensitivity to calibration drift. Porsche’s 1967 durability logs noted excellent high-RPM stability when maintained per specification, but modern operation without period-correct fuel or service intervals increases cam and lifter degradation. Cold-engine stress remains a key concern for longevity.
Analysis derived from Porsche technical bulletins (1966–1968) and EU historical vehicle documentation (2010–2023). Repair procedures should follow manufacturer guidelines.
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With strict adherence to maintenance and period-correct fluids, the 901.08 is robust and high-revving. Its DOHC design rewards precision care but suffers from cam wear if valve clearances or oil specs are neglected. Restored units with hardened valve seats and correct mineral oil can deliver decades of reliable performance.
Top issues include cam lobe wear from improper valve clearance, Bosch PI injection calibration drift, oil leaks from aged gaskets, and ignition timing instability due to distributor wear. All are well-documented in the 1966 Porsche 911S Workshop Manual.
Exclusively the 1966–1967 Porsche 911S (Type 901/08). Approximately 2,200 units were produced for road use, primarily to satisfy FIA homologation for Group 3 racing. No other models or manufacturers used this engine.
Yes. Common upgrades include 10.5:1 pistons, race camshafts, and modified injection, yielding ~180 PS. The DOHC bottom end is strong, but exceeding 190 PS requires reinforced connecting rods. Period-correct aesthetics are often preserved for historic racing eligibility.
Typical consumption is ~13.0 L/100km (city) and ~9.0 L/100km (highway), or about 22–26 mpg UK combined. Fuel economy is secondary to performance; aggressive driving can drop efficiency below 20 mpg UK.
No. Like all early air-cooled flat-six Porsche engines, the 901.08 is non-interference. Valve-to-piston contact will not occur if timing components fail, though valve float can still cause mechanical damage at high RPM.
Porsche specified SAE 20W-50 mineral oil meeting API SC/SD with high ZDDP (>1200 ppm) to protect flat-tappet cams. Modern synthetics are discouraged unless the engine is rebuilt with upgraded valvetrain components.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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