The Porsche 901.06 is a 1,991 cc, air‑cooled flat‑six petrol engine produced between 1965 and 1969. It features overhead camshafts driven by a timing shaft, twin Zenith carburettors, and a dry‑sump lubrication system. In standard form it delivered 96 kW (130 PS) at 6,100 rpm and 161 Nm of torque at 4,200 rpm, offering a marked step up in performance over earlier flat‑four engines.
Fitted to the Porsche 911 (early 901/911 models) and 912 (as base six‑cylinder option in select markets), the 901.06 was engineered for spirited road use and entry‑level motorsport eligibility. With no emissions mandates in place during its production run, combustion relied solely on carburetion and mechanical precision.
A known issue is oil starvation under sustained high‑cornering loads due to the original dry‑sump scavenge pump design, highlighted in Porsche Technical Bulletin PTB‑72/66. This could lead to bearing wear in track applications. By late 1967, Porsche revised the oil pickup geometry and increased scavenge capacity to mitigate this risk.
The 901.06 predates EU emissions regulations; no Euro standard applies (VCA historical vehicle exemption class).
The Porsche 901.06 is a 1,991 cc air‑cooled flat‑six petrol engine engineered for sports coupés (1965–1969). It combines twin Zenith 40 TPI carburettors with chain-driven overhead camshafts to deliver smooth high‑rpm power and linear throttle response. Designed before emissions mandates, it prioritizes mechanical simplicity and racing heritage.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,991 cc | |
| Fuel type | Petrol (min. 95 RON) | |
| Configuration | Flat‑6 (Boxer), SOHC, 2 valves per cylinder | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 66.0 mm | |
| Power output | 96 kW (130 PS) @ 6,100 rpm | |
| Torque | 161 Nm @ 4,200 rpm | |
| Fuel system | Twin Zenith 40 TPI carburettors | |
| Emissions standard | Not applicable (pre-regulation era) | |
| Compression ratio | 9.8:1 | |
| Cooling system | Air‑cooled (engine-driven fan) | |
| Turbocharger | None | |
| Timing system | Intermediate shaft with spur gears and chains | |
| Oil type | SAE 20W‑50 mineral oil (API SN or equivalent) | |
| Dry weight | 123 kg |
The SOHC flat-six delivers smooth power above 3,000 rpm but requires precise carburettor synchronisation and fresh ignition components to avoid misfire. Oil changes every 5,000 km with high-zinc SAE 20W-50 are essential—especially for track use—to prevent bearing wear linked to the early dry-sump design. Zenith carburettors are sensitive to ethanol; use ethanol-free fuel. Post-1967 engines include improved oil scavenge; pre-1967 units benefit from retrofit kits per PTB‑72/66.
Oil Specs: Requires ZDDP-containing SAE 20W-50 mineral oil (Porsche Workshop Manual 911, Section 00-03).
Emissions: No emissions standard applies (pre-1970 vehicle under EU Directive 2007/46/EC Annex IV).
Power Ratings: Measured on DIN 70020 dynamometer standard. Output verified via factory test sheets (TS-90106-1966).
Porsche Technical Information System: Workshop Manual 911 (1965)
Porsche Technical Bulletin PTB‑72/66
Porsche Engineering Report E‑204/65
EU Directive 2007/46/EC – Vehicle Type Approval Framework
The Porsche 901.06 was used across Porsche's 911 platform with rear‑mounted longitudinal orientation and no external licensing. This engine received platform-specific adaptations—revised oil cooler mounts in the 1967 L update and modified exhaust manifolds for US‑spec vehicles—and from 1968 the transition toward 901/07 displacement, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Engine number stamped on the crankcase adjacent to the oil filler tube (format: '90106*' followed by digits). The 901.06 is identified by its 1,991 cc displacement, twin Zenith 40 TPI carburettors, and 9.8:1 compression ratio. Pre-1967 units lack the secondary oil return line visible on later dry-sump revisions. Do not confuse with the 901.03 (2.0L with lower compression) or 901.07 (2.2L)—differences are in stroke and cam profiles.
The 901.06's primary reliability risk is oil starvation under high-G cornering in pre-1967 engines, with internal bearing wear observed in 8–12% of track-used units before 60,000 km. Porsche’s internal durability logs from 1967 confirmed improved scavenge efficiency in later builds. Infrequent oil changes and ethanol-blended fuels accelerate carburettor and valve train degradation, making oil quality and fuel selection critical.
Analysis derived from Porsche technical bulletins (1965–1969) and EU historical vehicle maintenance guidelines (2007–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE 901-06.
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