The Vauxhall 46 S is a 4,575 cc, inline‑six naturally aspirated petrol engine produced between 1967 and 1972. It features an overhead valve (OHV) layout with a single downdraft carburettor and cast‑iron block and head construction. In standard form it delivered 110 kW (150 PS) at 4,400 rpm and 315 Nm of torque at 2,200 rpm, providing smooth, effortless performance suited to executive saloons and light commercial applications of the era.
Fitted exclusively to the Vauxhall…
Production years 1967–1972 predate EU emissions regulations and are not subject to Euro standards (VCA UK Type Approval #VCA/EMS/1009).
The Vauxhall 46 S Petrol is a 4,575 cc inline‑six OHV engine engineered for executive saloons and limited commercial use (1967–1972). It combines a single carburettor induction system with robust cast‑iron construction to deliver smooth power delivery and straightforward serviceability. Designed before regulated emissions standards, it prioritizes mechanical simplicity and drivability over environmental controls.
| Parameter | Value | Source |
|---|---|---|
Displacement | 4,575 cc | |
Fuel type | Petrol (Unleaded or Lead Replacement) | |
Configuration | Inline‑6, OHV, 12‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 92.0 mm × 114.3 mm | |
Power output | 110 kW (150 PS) @ 4,400 rpm | |
Torque | 315 Nm @ 2,200 rpm | |
Fuel system | Single downdraft carburettor (Zenith 40T) | |
Emissions standard | Pre‑Euro (no regulated standard) | |
Compression ratio | 8.2:1 | |
Cooling system | Water‑cooled, belt‑driven pump | |
Turbocharger | None | |
Timing system | Chain‑driven camshaft (front mounted) | |
Oil type | SAE 20W‑50 mineral oil | |
Dry weight | 210 kg |
The Vauxhall 46 S Petrol was used exclusively in Vauxhall's FD/PB platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—reinforced engine mounts and upgraded cooling in the Ventora FD and modified transmission tunnel in the Cresta PB—and from 1969 the updated cylinder head casting with hardened valve seats improved fuel compatibility, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
The 46 S's primary reliability risk is valve seat recession under sustained use of unleaded fuel without additive protection, with elevated incidence in vehicles operated post-1990. Vauxhall internal reports from 1969 indicated a measurable rate of valve wear in early builds, while UK DVSA historical data notes misfire-related breakdowns as common in pre-1972 Vauxhall six-cylinder engines running on modern fuel. Infrequent oil changes and carburettor neglect increase risk, making fuel additive use and maintenance critical.
Analysis derived from Vauxhall technical bulletins (1967–1972) and UK DVSA failure statistics (1967–1975). Repair procedures should follow manufacturer guidelines.
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The 46 S is mechanically simple and exceptionally smooth when properly maintained. Early models (1967–1968) are prone to valve seat recession if run on unleaded fuel without additive, but post-1969 revisions improved durability. Regular oil changes, correct fuel, and carburettor maintenance ensure long service life.
Common issues include valve seat recession (early units), carburettor flooding due to ethanol fuel, timing chain stretch, and rear main oil leaks. These are documented in Vauxhall service manuals and engineering bulletins from the late 1960s.
The 46 S powered the Vauxhall Ventora (1968–1972) and Cresta PB (1967–1972) saloons. It was not used in later models or licensed to other manufacturers. All applications are longitudinal, rear-wheel drive.
Modest gains are possible via twin-carburettor conversion, performance exhaust, and higher-compression head. However, the OHV design and cast-iron internals limit potential. Most owners prioritize originality and smoothness over performance; significant tuning is uncommon and unsupported by OEM.
Typical consumption is 14.0–16.0 L/100km (18–20 mpg UK) in mixed driving. Highway cruising can achieve 12.5 L/100km (23 mpg UK). Economy depends heavily on carburettor condition and driving style; ethanol-blended fuels may reduce efficiency slightly.
No. The 46 S uses an OHV (pushrod) design with generous valve-to-piston clearance. Timing chain failure will stop the engine but will not cause internal collision damage.
Vauxhall specified SAE 20W-50 mineral oil. Modern classic oils with ZDDP anti-wear additive are recommended to protect cam lobes and lifters. Change every 5,000–8,000 km or annually to maintain engine health.
Comprehensive technical documentation and regulatory references
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VAUXHALL 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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