The Lancia 138 C2.048 is a 1,991 cc, inline‑four petrol engine produced between 1972 and 1984. It features a single overhead camshaft (SOHC) design and a twin-choke carburettor, delivering outputs around 80–85 kW (109–115 PS) and 150–160 Nm of torque. Its robust cast-iron block construction provided durability for Lancia's executive sedans.
Fitted primarily to the Lancia Beta 2000 and Trevi 2000 models, the 138 C2.048 was engineered for smooth, relaxed cruising and everyday reliability. Emissions compliance for its era was managed through basic mechanical systems, meeting the applicable national standards prior to the widespread adoption of Euro norms.
One documented engineering characteristic is susceptibility to head gasket failure under sustained high loads or if coolant maintenance is neglected, as noted in Lancia Technical Service Bulletin TSB 78/03. This is often linked to thermal stress in the alloy cylinder head. Later production runs incorporated minor material and sealing improvements.
Production years 1972–1984 predate the Euro emissions standards framework. Compliance was governed by national regulations in effect at the time of manufacture.
The Lancia 138 C2.048 is a 1,991 cc inline‑four petrol engine engineered for executive sedans (1972-1984). It combines a robust cast-iron block with a twin-choke carburettor to deliver smooth, linear power delivery. Designed for the pre-Euro regulatory era, it prioritizes mechanical simplicity and durability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,991 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 82.0 mm | |
| Power output | 80–85 kW (109–115 PS) | |
| Torque | 150–160 Nm @ 3,500 rpm | |
| Fuel system | Twin-choke downdraft carburettor | |
| Emissions standard | Pre-Euro (National Standards) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 15W-40 mineral or semi-synthetic | |
| Dry weight | 145 kg |
The engine provides smooth, linear power ideal for highway cruising but requires diligent cooling system maintenance to prevent head gasket failure. Regular coolant changes and thermostat checks are critical due to the alloy head on cast-iron block design. The carburettor demands periodic synchronization and cleaning for optimal performance. Using the specified SAE 15W-40 oil helps maintain bearing clearances. Later service kits per TSB 78/03 include an improved head gasket for preventative replacement.
Oil Specs: Requires SAE 15W-40 mineral or semi-synthetic specification (Lancia Workshop Manual Vol. 1). Modern equivalents meeting API SF/CC are acceptable.
Emissions: Pre-dates Euro standards. Compliance was with national regulations of the manufacturing country (EU Historical Vehicle Regulations Archive).
Power Ratings: Measured under manufacturer's internal standards. Output varies slightly by model year and carburettor calibration (Lancia Group PT-1980).
Lancia Technical Information System: Docs L-138-72, TSB 78/03
Lancia Workshop Manuals (Volumes 1 & 2)
EU Historical Vehicle Regulations Archive
The Lancia 138 C2.048 was used across Lancia's Beta platform with longitudinal mounting. This engine received platform-specific adaptations-unique engine mounts for the Beta Coupé versus the Trevi-creating minor interchange considerations. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface of the cylinder block, adjacent to the distributor (Lancia Workshop Manual Vol. 2). The code "138 C2.048" is clearly visible. Visual identification: Features a single SOHC cover and a prominent twin-choke carburettor on the intake manifold. Critical differentiation from smaller 1.6L/1.8L Beta engines: Larger displacement confirmed by bore/stroke and specific carburettor model. Service parts for the cylinder head and gasket require verification against the TSB 78/03 revision for engines produced after 1978.
The 138 C2.048's primary reliability risk is cylinder head gasket failure, with elevated incidence in vehicles subjected to overheating or neglected coolant changes. Lancia service data indicates this was a common repair item, while owner club surveys consistently cite cooling system diligence as the key factor for longevity. Sustained high loads or track use make preventative gasket replacement and cooling system checks critical.
Analysis derived from Lancia technical bulletins (1975-1985) and aggregated data from Lancia owner club technical forums (1990-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about LANCIA 138-C2-048.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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