The Porsche 911.52 is a 2,994 cc, air‑cooled flat‑six (boxer) petrol engine produced between 1976 and 1977. It features K-Jetronic continuous mechanical fuel injection, overhead valve (OHV) layout, and dry sump lubrication. In standard form it delivered 147 kW (200 PS) at 6,300 rpm with 265 Nm of torque at 4,800 rpm, engineered for responsive performance while meeting emerging emissions mandates.
Fitted exclusively to the Porsche 911 Carrera 3.0 (G-series) for European and select export markets, the 911.52 was designed to balance power, drivability, and compliance with early Euro 1-equivalent national standards. Driving character emphasizes linear throttle response, strong mid-range torque, and high-revving smoothness typical of air-cooled flat-six engines.
A documented concern is thermal stress cracking in the magnesium crankcase near the oil pickup tube under sustained high-load conditions. This issue, highlighted in Porsche Technical Bulletin PTB‑76/03, was linked to casting inconsistencies in early 1976 production units. From mid‑1976 onward, revised alloy composition and improved cooling duct routing mitigated the risk.
Production years 1976–1977 meet pre‑Euro national emissions standards; formal Euro classification does not apply (KBA Germany Type Approval #15982).
The Porsche 911.52 is a 2,994 cc flat‑six air‑cooled petrol engine engineered for the 911 Carrera 3.0 (1976–1977). It combines Bosch K-Jetronic mechanical injection with OHV architecture to deliver smooth power delivery and enhanced emissions control. Designed before formal Euro regimes, it relies on thermal efficiency and mechanical precision to meet contemporary West German type approval requirements.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,994 cc | |
| Fuel type | Petrol (Leaded, compatible with unleaded with upgrades) | |
| Configuration | Flat‑6 (boxer), OHV, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 95.0 mm × 70.4 mm | |
| Power output | 147 kW (200 PS) @ 6,300 rpm | |
| Torque | 265 Nm @ 4,800 rpm | |
| Fuel system | Bosch K-Jetronic continuous injection | |
| Emissions standard | Pre‑Euro (national type approval only) | |
| Compression ratio | 8.5:1 | |
| Cooling system | Air‑cooled (fan‑driven) | |
| Turbocharger | None | |
| Timing system | Gear‑driven camshaft | |
| Oil type | SAE 20W-50 mineral oil (API SF/CC) | |
| Dry weight | 135 kg |
The K-Jetronic system provides precise fuel metering but requires periodic calibration of the fuel distributor and warm-up regulator to maintain mixture stability. Operation on modern unleaded fuel necessitates hardened valve seats to prevent recession. Dry-sump oil checks must be performed with the engine running. Use only non-detergent SAE 20W-50 mineral oil with ZDDP to protect cam lobes. Early 1976 crankcases are prone to thermal cracking; inspect oil pickup area for hairline fractures using dye penetrant per PTB‑76/03.
Oil Specs: Requires non-detergent SAE 20W-50 mineral oil (API SF/CC) per Porsche Lubricants Guide 1976.
Emissions: Pre-Euro emissions regime; governed by KBA Germany national type approval (KBA #15982). No Euro classification applies.
Power Ratings: Measured per DIN 70020 standard. Output verified in KBA approval documentation.
Porsche Werkstatthandbuch 911 (1976)
Porsche Technical Bulletin PTB-76/03
Kraftfahrt-Bundesamt (KBA) Type Approval Database #15982
Porsche Engineering Report ER-911/77
The Porsche 911.52 was used exclusively in the Porsche 911 Carrera 3.0 (G-series) with rear-engine, longitudinal mounting. Platform-specific adaptations included reinforced engine mounts and revised cooling shrouds to accommodate larger 3.0 L displacement. Early 1976 units used original magnesium alloy cases, while mid‑1976 onward adopted improved material composition per PTB‑76/03, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped on the crankcase adjacent to the oil filler tube (Porsche Werkstatthandbuch 911/1976). The prefix '911/52' confirms this variant. Visual identification includes the Bosch K-Jetronic fuel distributor on the intake side, air-cooled cylinder fins, and dry-sump oil tank. Differentiate from 930 turbo engines by absence of turbocharger and intercooler. Early 1976 crankcases may lack revised oil pickup reinforcement.
The 911.52's primary reliability risk is thermal stress cracking in early magnesium crankcases under sustained high-load operation. Porsche internal quality data from 1976 noted elevated case failures in pre-mid‑1976 builds, while KBA workshop reports identify K-Jetronic calibration drift as a frequent cause of rough running. Extended high-RPM use without oil changes accelerates cam lobe wear, making oil quality and fuel system maintenance critical.
Analysis derived from Porsche technical bulletins (1976–1979) and Kraftfahrt-Bundesamt (KBA) failure statistics (1977–1981). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE 911-52.
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