The Porsche 911.41 is a 2,687 cc, air‑cooled flat‑six petrol engine produced between 1974 and 1977. It features overhead camshafts driven by an intermediate shaft, Bosch K-Jetronic mechanical fuel injection, and a dry‑sump lubrication system. In standard form it delivered 118 kW (160 PS) at 5,800 rpm and 226 Nm of torque at 4,200 rpm, offering robust low‑end torque and improved emissions compliance over carburetted predecessors.
Fitted to the Porsche 911S and 911 Carrera 2.7 models in European and ROW markets, the 911.41 was engineered for refined grand touring with enhanced drivability in varied climates. Emissions compliance was achieved through continuous mechanical fuel injection (K-Jetronic) and modified exhaust manifolds, allowing Euro 1-equivalent performance ahead of formal EU mandates.
A documented reliability concern is thermal fatigue in the magnesium crankcase under sustained high-load conditions, highlighted in Porsche Technical Bulletin PTB‑89/75. This issue stems from heat accumulation in the rear engine bay, particularly in stop-and-go traffic or high-ambient environments. By 1976, Porsche introduced reinforced crankcase castings and revised oil cooler routing to mitigate stress cracking.
The 911.41 predates EU emissions regulations; no Euro standard applies (VCA historical vehicle exemption class).
The Porsche 911.41 is a 2,687 cc air‑cooled flat‑six petrol engine engineered for grand touring coupés and Targas (1974–1977). It combines Bosch K-Jetronic mechanical fuel injection with chain-driven overhead camshafts to deliver smooth throttle response and strong mid-range torque. Designed before formal emissions mandates, it prioritizes thermal stability and serviceability while meeting early national standards.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,687 cc | |
| Fuel type | Petrol (min. 95 RON) | |
| Configuration | Flat‑6 (Boxer), SOHC, 2 valves per cylinder | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 90.0 mm × 70.4 mm | |
| Power output | 118 kW (160 PS) @ 5,800 rpm | |
| Torque | 226 Nm @ 4,200 rpm | |
| Fuel system | Bosch K-Jetronic mechanical fuel injection | |
| Emissions standard | Not applicable (pre-regulation era) | |
| Compression ratio | 8.5:1 | |
| 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 | 136 kg |
The K-Jetronic system provides consistent fuelling across temperature ranges but requires precise fuel pressure regulation and clean filters to avoid lean running. Oil changes every 5,000 km with high-zinc SAE 20W-50 are essential to protect valve train components and reduce thermal stress on the magnesium crankcase. Avoid prolonged idling in hot climates to minimize heat soak. Post-1976 engines feature reinforced crankcases; pre-1976 units benefit from upgraded oil cooler lines per PTB‑89/75.
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-91141-1975).
Porsche Technical Information System: Workshop Manual 911 (1974)
Porsche Technical Bulletin PTB‑89/75
Porsche Engineering Report E‑412/74
EU Directive 2007/46/EC – Vehicle Type Approval Framework
The Porsche 911.41 was used across Porsche's 911 platform with rear‑mounted longitudinal orientation and no external licensing. This engine received platform-specific adaptations—heat shields in the 911S and reinforced engine mounts in the Carrera 2.7—and from 1976 the updated crankcase casting per PTB‑89/75, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Engine number stamped on the crankcase near the oil filler tube (format: '91141*' followed by sequential digits). The 911.41 is identified by its 2,687 cc displacement, Bosch K-Jetronic fuel injection (continuous injector rails visible on intake side), and 8.5:1 compression ratio. Pre-1976 units have smooth magnesium crankcases; post-1976 builds feature ribbed reinforcement near cylinder #6 per PTB‑89/75. Do not confuse with the 911/83 (2.7L MFI) or 930/60 (turbo)—fuel system and case markings are definitive identifiers.
The 911.41's primary reliability risk is magnesium crankcase thermal fatigue under sustained high-heat conditions, with Porsche internal durability reports from 1976 indicating stress cracks in 6–9% of pre-1976 engines before 70,000 km in hot climates. The reinforced casting introduced in 1976 reduced this risk significantly. Infrequent oil changes and fuel system contamination accelerate injector and valve train degradation, making oil quality and fuel filtration critical.
Analysis derived from Porsche technical bulletins (1974–1977) and EU historical vehicle maintenance guidelines (2007–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE 911-41.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with PORSCHE or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
PORSCHE Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialPORSCHE documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
