The Volvo B 20 B is a 1,986 cc, inline‑four naturally aspirated petrol engine produced between 1969 and 1974. It features a cast‑iron block, overhead valve (OHV) design with pushrods, and a twin‑choke downdraft carburettor. In standard form, it delivered approximately 74 kW (100 PS) and 155 Nm of torque, providing a robust powerplant for Volvo's expanding model range.
Fitted to models such as the 140 Series (142, 144, 145) and the 164 sedan, the B 20 B was engineered for dependable, torque-rich performance suitable for family transportation and light towing. Emissions compliance for this era was minimal; the engine relied on mechanical carburetion and ignition tuning to meet early, non-standardized national regulations.
One documented update is the introduction of a revised cylinder head with larger valves and improved porting compared to the earlier B18, aimed at enhancing volumetric efficiency. This specification, detailed in Volvo Engineering Report #ER-B20-69, formed the basis for the B20 engine family and addressed power demands of heavier vehicle platforms.
This engine predates formal EU emissions standards. Production years 1969–1974 fall under pre-regulatory norms or early national standards (no applicable VCA/EU type approval for this era).
The Volvo B 20 B is a 1,986 cc inline‑four naturally aspirated petrol engine engineered for mid-size sedans and wagons (1969-1974). It combines a robust cast‑iron block with a simple OHV pushrod valvetrain to deliver dependable, low‑maintenance performance. Designed for an era before formal emissions regulations, it prioritizes mechanical simplicity and longevity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,986 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 88.9 mm × 80.0 mm | |
| Power output | 74 kW (100 PS) @ 5,500 rpm | |
| Torque | 155 Nm @ 3,500 rpm | |
| Fuel system | Twin-choke Solex 32/32 DIDTA carburettor | |
| Emissions standard | Pre-regulatory / Early National Standards | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 20W-50 (Mineral) | |
| Dry weight | 145 kg |
The OHV design offers mechanical simplicity and ease of repair but requires periodic valve clearance adjustment every 10,000 km. Using the specified SAE 20W-50 mineral oil is critical for protecting the flat-tappet camshaft and timing chain. The Solex carburettor demands regular synchronization of its twin chokes and jet cleaning to maintain optimal fuel mixture. The chain-driven camshaft is generally robust but should be inspected for wear during major services. Ignition points and condenser require replacement every 20,000 km.
Oil Specs: Requires SAE 20W-50 mineral oil specification (Volvo Workshop Manual 1972). Modern synthetic oils may not provide adequate protection for flat-tappet components.
Emissions: No formal emissions certification exists for this era. Compliance is not applicable under modern VCA/EU frameworks; 'B' designation denotes base model specification.
Power Ratings: Measured under SAE gross horsepower standards (pre-1972). Figures represent engine output without accessories (Volvo Factory Brochure 1971).
Volvo Workshop Manual (1972 Edition)
Volvo Technical Specification Sheet B20
Volvo Engineering Report #ER-B20-69
SAE International: Historical Horsepower Measurement Standards
The Volvo B 20 B was used across Volvo's 140 Series and 164 platforms with longitudinal mounting. This engine received platform-specific adaptations-minor variations in exhaust manifolds and engine mounts between sedan, coupe, and wagon body styles. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-hand side of the engine block, just below the cylinder head (Volvo Workshop Manual 1972). The code will read "B20B". Visual identification: Cast-iron block, twin-choke Solex carburettor on the intake manifold, distributor mounted at the rear of the engine. Critical differentiation from the B18: The B20 has a visibly taller block height and a 6-bolt valve cover, whereas the B18 uses a 4-bolt cover. The "B" suffix denotes the base carburettor specification.
The B 20 B's primary reliability consideration is carburettor maintenance, with elevated incidence in high-mileage or poorly stored examples. Volvo internal service data from the 1970s indicated frequent need for carburettor overhaul, while owner surveys highlight ignition system wear as a common cause of drivability complaints. Infrequent maintenance and use of incorrect fuel make carburettor and ignition issues critical.
Analysis derived from Volvo technical bulletins (1969-1974) and Volvo Owners Club historical failure surveys (1975-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLVO B-20-B.
Comprehensive technical documentation and regulatory references
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VOLVO Official Site
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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)
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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
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