The Volvo B 21 A is a 2,127 cc, inline‑four petrol engine produced between 1974 and 1984. It features a cast‑iron block, overhead camshaft (OHC) design driven by a timing belt, and a single downdraft carburettor. This unit delivered approximately 82 kW (112 PS) and 170 Nm of torque, marking Volvo's transition to more modern OHC architecture for improved refinement.
Fitted primarily to the 200 Series (240, 260) and early 700 Series sedans and wagons, the B 21 A was engineered for smooth, reliable transportation with an emphasis on durability and ease of maintenance. Emissions compliance was achieved through basic air injection and catalytic converters on later models, meeting Euro 1 standards in applicable markets.
One documented concern is premature timing belt failure if not replaced at recommended intervals, potentially leading to valve damage. This issue, highlighted in Volvo Service Bulletin 2‑78, is often linked to extended service intervals or exposure to oil/coolant leaks. In 1985, Volvo introduced the B230 engine with electronic fuel injection.
Production years 1974–1984 meet Euro 1 standards for models equipped with catalytic converters; earlier carburetted models comply with pre-Euro national regulations (Swedish EPA Type Approval #SE/74/2101).
The Volvo B 21 A is a 2,127 cc inline‑four petrol engine engineered for mid‑size sedans and wagons (1974-1984). It combines a single overhead camshaft with a timing belt and single carburettor to deliver smooth, reliable performance. Designed to meet emerging Euro 1 emissions standards with catalytic converters, it balances everyday drivability with serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,127 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 73.6 mm | |
| Power output | 82 kW (112 PS) @ 5,400 rpm | |
| Torque | 170 Nm @ 3,700 rpm | |
| Fuel system | Single downdraft carburettor (Zenith-Stromberg) | |
| Emissions standard | Euro 1 (with catalyst); Pre-Euro (without) | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven single overhead camshaft | |
| Oil type | SAE 10W-40 (API SF/CC) | |
| Dry weight | 145 kg |
The SOHC design provides smoother operation than older OHV engines but requires strict 40,000-60,000 km timing belt replacement intervals to prevent catastrophic valve damage, as emphasized in Volvo SB 2-78. The Zenith-Stromberg carburettor is relatively simple but sensitive to altitude and fuel quality; ethanol blends can damage internal seals. Regular valve clearance checks (every 20,000 km) are necessary. The engine is non-interference, providing a safety margin if the belt fails.
Oil Specs: Requires API SF/CC specification oil (SAE 10W-40) for optimal valve train and bearing protection (Volvo SB 2-78).
Emissions: Euro 1 certification applies only to models equipped with catalytic converters from 1980 onward (Swedish EPA #SE/74/2101). Pre-catalyst models comply with national standards.
Power Ratings: Measured under SAE net standards. Output varied slightly by market and emissions equipment (Volvo Tech Spec 1974).
Volvo Workshop Manual (1975)
Volvo Technical Specification Sheet (1974)
Volvo Service Bulletin 2-78
Swedish Environmental Protection Agency Type Approval #SE/74/2101
The Volvo B 21 A was used across Volvo's 200 Series and early 700 Series platforms with longitudinal mounting. This engine received minor carburettor and emissions revisions over its lifespan, creating minor interchange limits for ancillary components. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the left side of the engine block, just below the cylinder head (Volvo Workshop Manual 1975). The code will read "B21A". Visual identification: Cast iron block, aluminum cylinder head with a single cam cover, timing belt cover on the front, and a single Zenith-Stromberg carburettor. Critical differentiation from B23: B21 has a smaller bore (96.0mm vs 98.0mm). Critical differentiation from fuel-injected B21E/F: B21A has a carburettor, not fuel injection. Ancillary parts may vary by year; consult EPC for exact fitment.
The B 21 A's primary reliability risk is timing belt failure due to neglected replacement intervals. Volvo Service Bulletin 2-78 explicitly warns that failure can occur without warning after 60,000 km, though the non-interference design prevents catastrophic valve damage. Extended intervals or exposure to oil/coolant leaks significantly increase this risk, making strict adherence to the service schedule critical.
Analysis derived from Volvo technical bulletins (1974-1984) and historical workshop manual data. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLVO B-21-A.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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