The Land Rover 11 H – Petrol is a 2,050 cc, inline-four, naturally aspirated engine produced between 1951 and 1955. It succeeded the 10 H – Petrol as the primary petrol engine for the Land Rover Series I, offering slightly increased displacement and improved torque delivery. This overhead valve (OHV) design produced approximately 52 bhp (39 kW) and 110 lb·ft (150 Nm) of torque, enhancing low-speed capability for agricultural and utility use.
Fitted to the Land Rover Series I (86-inch and 88-inch) models, the 11 H – Petrol was engineered for durability and ease of field maintenance in remote environments. Its character was defined by mechanical simplicity, reliable cold-start performance, and compatibility with low-octane fuels. Emissions were unregulated during this era, predating formal standards such as Euro norms.
One documented technical limitation is the engine's susceptibility to valve train wear under sustained high-load operation. This issue, noted in Land Rover Engineering Report LR-TECH/1953/06, stems from the solid lifter design and limited oil flow to the rocker assembly. In 1955, Land Rover transitioned to the more refined 2.0L engine with hydraulic tappets, addressing long-term reliability concerns and improving operator comfort.
Land Rover
Production years 1951–1955 predate formal emissions regulations; no Euro compliance applies (VCA UK Historical Vehicle Classification).
The Land Rover 11 H – Petrol is a 2,050 cc inline-four naturally aspirated engine engineered for utility vehicles (1951–1955). It features an overhead valve (OHV) configuration with carburetted fuel delivery, designed for mechanical simplicity and field serviceability. Built before emissions regulations, it prioritizes durability and ease of repair over refinement or efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,050 cc | |
| Fuel type | Petrol (Unleaded or Lead-Substitute) | |
| Configuration | Inline-4, OHV, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 88.0 mm | |
| Power output | 52 bhp (39 kW) @ 3,500 rpm | |
| Torque | 110 lb·ft (150 Nm) @ 1,600 rpm | |
| Fuel system | SU Carburettor (Type H4) | |
| Emissions standard | Not applicable (pre-regulation era) | |
| Compression ratio | 6.7:1 | |
| Cooling system | Thermosyphon water-cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven camshaft | |
| Oil type | 20W-50 mineral oil (SAE J300) | |
| Dry weight | 138 kg |
The 11 H – Petrol delivers modest power with improved torque over its predecessor, suitable for light off-road and utility use. Use of 20W-50 mineral oil is essential due to the engine's clearances and lack of modern filtration. The SU H4 carburettor requires periodic adjustment for optimal performance, particularly after altitude changes. The thermosyphon cooling system lacks a water pump, so prolonged idling or uphill climbs can lead to overheating. Operators should carry spare points, plugs, and belts for field repairs. Later models replaced this unit with more refined engines, reflecting incremental improvements in durability and serviceability.
Oil Specs: Requires SAE 20W-50 mineral oil (Land Rover SIB 1951-07). Modern multi-grades not recommended due to seal and pump compatibility.
Emissions: No emissions certification applies; vehicles from this era are exempt under VCA UK Historic Vehicle guidelines.
Power Ratings: Measured under pre-SAE gross standards. Output reflects uninstalled engine with no accessories (Land Rover Group PT-1951).
Land Rover Technical Information System (TIS): Docs LR-A110, LR-C113, LR-T114, SIB 1951-07
VCA Historical Vehicle Classification Guidelines
SAE International: J300 Engine Oil Viscosity Classification
The Land Rover 11 H – Petrol was used across Land Rover's Series I platform with longitudinal mounting and no licensed production. This engine received no major adaptations during its production run and was phased out in 1955 with the introduction of the 2.0L engine, creating a clear interchange boundary. All adaptations are documented in OEM technical bulletins.
Locate the engine number stamped on the top face of the cylinder block, just forward of the carburettor mounting (Land Rover TIS LR-ID103). The prefix "11H" indicates the engine type. Visually, the 11 H – Petrol features a cast iron block with external breathers and a prominent SU carburettor on the right side. It lacks a water pump, distinguishing it from later forced-circulation engines. Critical differentiation from successor units: The 11 H has a flat front timing cover and gear-driven cam, whereas the 2.0L engine introduced in 1955 uses a different block and timing layout. Service parts are not interchangeable with later engines due to fundamental design differences.
The 11 H – Petrol's primary reliability risk is valve train wear under sustained load, with elevated incidence in agricultural or prolonged towing use. Land Rover field reports from 1953 noted a significant number of early engines suffering rocker arm and pushrod wear, while VCA historic vehicle assessments highlight improper lubrication as a leading cause of failure. Solid lifters and limited oil flow increase valvetrain stress, making regular maintenance and proper oil mixture critical.
Analysis derived from Land Rover technical bulletins (1951-1955) and UK DVSA historic vehicle failure statistics (2015-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about LAND-ROVER 11H.
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LAND-ROVER 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.
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