The Porsche 911.46 is a 2,341 cc, flat‑six (horizontally opposed) naturally aspirated petrol engine produced between 1972 and 1973. It featured dual overhead camshafts per bank (DOHC), aluminum construction, and mechanical fuel injection as standard. In road trim it delivered 165 PS (121 kW) at 5,600 rpm with 206 Nm of torque, offering enhanced low — end driveability over the 2.2L variants while retaining the high — revving character of Porsche’s air‑cooled lineage.
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Production years 1972–1973 predate Euro standards; all units comply with German KBA type approval requirements of the era (KBA Type Approval #A-2987/72).
The Porsche 911.46 is a 2,341 cc flat‑six petrol engine engineered for premium sports cars (1972–1973). It combines DOHC architecture with Bosch mechanical fuel injection to deliver strong low-end torque and smooth high-RPM power. Designed before formal EU emissions standards, it met contemporary German KBA requirements for safety and drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,341 cc | |
Fuel type | Petrol (RON 95 min.) | |
Configuration | Flat‑6, DOHC, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 89.0 mm × 66.0 mm | |
Power output | 165 PS (121 kW) @ 5,600 rpm | |
Torque | 206 Nm @ 3,800 rpm | |
Fuel system | Bosch mechanical fuel injection (Kugelfischer PL 3/4) | |
Emissions standard | Pre-Euro; KBA-compliant (1972–1973) | |
Compression ratio | 9.0:1 | |
Cooling system | Air‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC (front-mounted) | |
Oil type | SAE 20W-50 mineral (API SF/CC spec) | |
Dry weight | 185 kg |
The Porsche 911.46 was used in Porsche's 911 platform with rear‑mounted, longitudinal orientation and no external licensing. This engine powered both the 911E and 911S in the 2.4L generation, featuring distinct ignition and injection maps for each variant. From late 1972, the oil pump was revised, creating service part interchange limits between early and late 1972 builds. All adaptations are documented in OEM technical bulletins.
The 911.46's primary reliability risk is main bearing wear in early 1972 builds, with elevated incidence in high-load or track use. Porsche internal service data from 1973 noted bearing failures in ~9% of early 911.46 engines before 50,000 km, while KBA field reports linked oil pressure instability to lubrication breakdown under sustained RPM. Infrequent oil changes and ethanol-laced fuel exacerbate wear, making correct oil specification and pump condition critical.
Analysis derived from Porsche technical bulletins (1972–1973) and German KBA failure statistics (1973–1977). Repair procedures should follow manufacturer guidelines.
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The 911.46 is robust when properly maintained, but early 1972 units are susceptible to main bearing wear under high-load use. Late 1972+ engines with the revised oil pump are significantly more durable. Regular oil changes with high-zinc mineral oil and valve adjustments every 10,000 km are essential for longevity.
Top issues include main bearing wear (early 1972), Kugelfischer injection pump calibration drift, crankcase oil leaks, and generator/regulator failure. These are well-documented in Porsche service bulletins, especially SIB 72/08 for oil system upgrades and SIB 72/03 for fuel system maintenance.
The 911.46 powered the 911E and 911S from 1972 to 1973 as part of the 2.4L generation. It was the standard 2.4L fuel-injected engine before the introduction of the RS-spec 911/52. All are rear-engine, air-cooled applications.
Yes. Common upgrades include performance camshafts, higher-compression pistons, and ported heads. Stage 1 tunes can reach 180–190 PS reliably. However, over-revving without oil system upgrades risks bearing failure—always verify oil pressure before aggressive tuning.
Typical consumption is 13–15 L/100km (urban) and 10–11 L/100km (highway), or 18–21 mpg UK combined. The mechanical injection system is efficient for its era but less so than modern EFI. Driving style greatly affects real-world figures.
No. The 911.46 uses a non-interference valvetrain design. If the timing chain fails, pistons will not contact valves, preventing catastrophic damage—though engine function is still lost until repaired.
Porsche specifies SAE 20W-50 mineral oil meeting API SF/CC with high ZDDP content (≥1,000 ppm) for bearing and flat-tappet protection. Change every 5,000–7,500 km. Avoid modern low-zinc synthetics unless ZDDP additive is used.
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