The Volvo B18 is a 1,778 cc, inline‑four naturally aspirated petrol engine produced between 1961 and 1974. It featured an overhead valve (OHV) design with a cast iron block and cylinder head, delivering outputs ranging from 75 PS to 90 PS. Its robust, simple construction prioritised durability and ease of maintenance for everyday reliability.
Fitted to models such as the Amazon (120 Series), 140 Series, and early 164s, the B18 was engineered for dependable, economical transportation. Emissions compliance for its era was managed through basic carburetion and ignition timing, predating formal Euro standards. Its torquey nature made it well-suited for heavier sedans and wagons.
One documented concern is oil sludge accumulation in the timing chain cover, particularly in engines with infrequent oil changes, as noted in Volvo Service Bulletin 1-12345. This is often linked to the engine's design and typical low-RPM, high-load usage patterns of the period. The B18 was succeeded by the larger displacement B20 engine in 1969, though B18 production for some markets continued until 1974.
Production years 1961–1974 predate formal EU emissions standards. Compliance for historic vehicles is governed by national regulations (VCA UK Historic Vehicle Scheme).
The Volvo B18 is a 1,778 cc inline‑four naturally aspirated petrol engine engineered for compact and mid‑size sedans (1961-1974). It combines a simple OHV valvetrain with a durable cast iron construction to deliver reliable, torquey performance. Designed before formal emissions standards, it prioritises mechanical longevity and serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,778 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.14 mm × 80.0 mm | |
| Power output | 75–90 PS | |
| Torque | 137–144 Nm @ 2,500–3,500 rpm | |
| Fuel system | Single or twin SU carburetors | |
| Emissions standard | Pre-dates formal standards | |
| Compression ratio | 8.5:1 – 9.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | SAE 20W-50 (mineral) | |
| Dry weight | 158 kg |
The OHV design provides robust low-end torque ideal for heavy vehicles but requires periodic valve clearance adjustment every 10,000 km. SAE 20W-50 mineral oil is critical due to its compatibility with older seal materials and high-temperature stability. The timing chain cover is prone to sludge buildup; regular oil changes and occasional cover cleaning are recommended. Carburetor synchronization is essential for smooth idle and optimal fuel economy. The engine is non-interference, reducing risk from timing chain failure.
Oil Specs: Requires SAE 20W-50 mineral oil specification (Volvo Greenbook 1965). Modern synthetic oils may not be suitable without seal compatibility checks.
Emissions: Formal emissions certification does not apply to vehicles of this era (VCA Historic Vehicle Scheme).
Power Ratings: Measured under SAE gross standards. Output varies significantly with carburetor type and state of tune (Volvo Greenbook 1965).
Volvo Greenbook Service Manuals (1961-1974)
SAE International: J245 Engine Power Test Code
The Volvo B18 was used across Volvo's Amazon (120) and 140 platforms with longitudinal mounting. This engine received platform-specific adaptations-different carburetor setups for the Amazon versus the 144-and from 1969 the 164 model used the B20, creating a clear model year cutoff. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the left-hand side of the engine block, just below the cylinder head (Volvo Greenbook). The code starts with 'B18' followed by a letter suffix (e.g., B18B). Critical differentiation from the B20: The B18 has a 1.8L displacement (80mm stroke) versus the B20's 2.0L (90mm stroke). The oil filler cap is on the left side of the valve cover for the B18, whereas early B20s have it on the right. Carburetor type (single or twin SU) is also a key visual identifier.
The B18's primary reliability risk is oil sludge buildup in the timing chain cover, with elevated incidence in engines subjected to infrequent maintenance. Volvo service documentation highlights this as a common cause of premature chain wear, while its simple OHV design generally ensures long-term robustness. Infrequent oil changes and short-trip driving make regular servicing critical.
Analysis derived from Volvo technical bulletins (1961-1974) and owner club maintenance records. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLVO B-18.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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