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.
Fitted exclusively to the 911E and 911S (1972–1973), the 911.46 was engineered to balance emissions compliance with performance, using Bosch mechanical fuel injection and a revised exhaust system to meet early German environmental directives. Emissions controls remained minimal by modern standards; the engine predates EU frameworks but complied with contemporary KBA requirements.
One documented concern is main bearing wear under high-load conditions in early 1972 builds, highlighted in Porsche Service Information Bulletin SIB 72/08. This stems from marginal oil pressure stability at idle and elevated thermal stress on bearing shells during sustained operation. In late 1972, Porsche upgraded the oil pump relief valve and introduced improved bearing materials to enhance durability.
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 2.4L displacement provides strong torque below 4,000 rpm, ideal for spirited road use, but demands strict oil change intervals every 5,000–7,500 km using high-zinc mineral oil to protect bearings and cam lobes. Early 1972 engines are prone to main bearing wear due to marginal oil pressure at idle; late 1972+ units include an improved relief valve per Porsche SIB 72/08. Ethanol-free RON 95+ fuel is essential to preserve Kugelfischer injection calibration and prevent fuel system corrosion.
Oil Specs: Requires high-zinc SAE 20W-50 mineral oil (API SF/CC). Modern low-zinc synthetics lack ZDDP levels needed for bearing and flat-tappet protection.
Emissions: Pre-Euro engine; complies with 1972–1973 German KBA type approval (KBA #A-2987/72). No EU emissions certification applies.
Power Ratings: Measured under DIN 70020 standards. Output assumes RON 95 fuel and properly calibrated Kugelfischer injection (Porsche PT-1972).
Porsche Technical Information System (TIS): Docs 911-1146, SIB 72/03, SIB 72/08
Kraftfahrt-Bundesamt (KBA) Type Approval Database (A-2987/72)
DIN 70020 Engine Power Certification Standard
Porsche Engineering Report ER-72-05
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.
Locate the engine type stamped on the left crankcase near the oil filler neck (Porsche TIS 911-1146). The 911.46 appears as “911/46” or “Type 911/46”. All units feature black cam covers and Kugelfischer mechanical injection. Critical differentiation from 911/52 (2.4L RS): 911.46 has lower compression and standard camshafts. Early 1972 oil pumps have smooth housings; late 1972+ units use a ribbed housing with modified relief valve—verify before ordering replacements (Porsche SIB 72/08).
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.
Find answers to most commonly asked questions about PORSCHE 911-46.
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