The Volvo B 21 ET is a 2,127 cc, inline‑four naturally aspirated petrol engine produced between 1975 and 1980. It features a cast‑iron block, overhead valve (OHV) design with pushrods, and a twin‑choke downdraft carburettor. In standard form, it delivered approximately 85 kW (115 PS) and 170 Nm of torque, providing improved performance over its B20 predecessor.
Fitted to models such as the 240 Series (242, 244, 245) and the 260 Series, the B 21 ET was engineered for smooth, torque-rich performance suitable for larger family vehicles and light towing. Emissions compliance was met through revised carburetion and ignition timing, allowing compliance with emerging US and European regulations of the mid-1970s.
One documented update is the introduction of a revised cylinder head with hardened valve seats for unleaded fuel compatibility, as mandated by new fuel regulations. This specification, detailed in Volvo Engineering Report #ER-B21-75, was part of a broader transition to meet tightening global fuel and emissions standards without sacrificing engine durability.
Production years 1975–1980 meet early national emissions standards; no formal EU type approval existed for this era (VCA UK Historical Archive).
The Volvo B 21 ET is a 2,127 cc inline‑four naturally aspirated petrol engine engineered for mid-to-large size sedans and wagons (1975-1980). It combines a robust cast‑iron block with a simple OHV pushrod valvetrain to deliver dependable, low‑maintenance performance. Designed to meet early national emissions standards, it balances torque delivery with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,127 cc | |
| Fuel type | Petrol (Unleaded Compatible) | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 96.0 mm × 74.0 mm | |
| Power output | 85 kW (115 PS) @ 5,500 rpm | |
| Torque | 170 Nm @ 3,500 rpm | |
| Fuel system | Twin-choke Zenith-Stromberg 175 CD2SE carburettor | |
| Emissions standard | Early National Standards (US/EU) | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 20W-50 (Mineral) | |
| Dry weight | 150 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 Zenith-Stromberg 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 1978). Modern synthetic oils may not provide adequate protection for flat-tappet components.
Emissions: Meets early national standards only (VCA UK Historical Archive). No formal EU type approval existed for this era.
Power Ratings: Measured under SAE gross horsepower standards (pre-1972). Figures represent engine output without accessories (Volvo Factory Brochure 1977).
Volvo Workshop Manual (1978 Edition)
Volvo Technical Specification Sheet B21
Volvo Engineering Report #ER-B21-75
SAE International: Historical Horsepower Measurement Standards
The Volvo B 21 ET was used across Volvo's 240 Series and 260 Series 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 1978). The code will read "B21ET". Visual identification: Cast-iron block, twin-choke Zenith-Stromberg carburettor on the intake manifold, distributor mounted at the rear of the engine. Critical differentiation from the B23: The B21 has a visibly shorter stroke and different bore size. The "ET" suffix denotes the emissions-tuned specification with hardened valve seats for unleaded fuel.
The B 21 ET'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 (1975-1980) and Volvo Owners Club historical failure surveys (1980-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLVO B-21-ET.
Comprehensive technical documentation and regulatory references
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VOLVO 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
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