The Fiat 138 B.000 is a 1,585 cc inline-four petrol engine produced between 1979 and 1985. It powered the mid-range Fiat 138 saloon, delivering 62 kW (84 PS) with 124 Nm of torque. Featuring a cast-iron block, SOHC valvetrain, and single-choke carburettor (Weber 32/34 DCF), it was engineered for economy and ease of maintenance in family-oriented applications.
Fitted to the Fiat 138 1.6 and 1.6S variants, the B.000 was tuned for responsive urban driving and moderate highway cruising. Its design prioritized fuel efficiency and low maintenance costs, making it suitable for European markets with high fuel prices. Emissions control was achieved via precision carburetion and early evaporative emission systems, allowing compliance with pre-Euro standards applicable during its production run.
One documented engineering update occurred in 1981, referenced in Fiat Service Information Bulletin B-81-06, involving revised valve stem seal design to reduce oil consumption in high-mileage engines. This update improved long-term durability and was retrofittable to earlier builds, reflecting Fiat's incremental development strategy during the early 1980s.
Production years 1979–1985 comply with pre-Euro European emissions directives (EEC 70/220) as implemented in Italy and EU markets (Italian Ministry of Transport Type Approval #MIT/79/B000).
The Fiat B.000 is a 1,585 cc inline-four petrol engine engineered for compact family sedans (1979–1985). It combines SOHC architecture with single-choke carburetion to deliver balanced performance and mechanical simplicity. Designed to meet early emissions regulations, it balances economy with serviceability for daily driving applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,585 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 78.0 mm × 82.0 mm | |
| Power output | 62 kW (84 PS) | |
| Torque | 124 Nm @ 2,800 rpm | |
| Fuel system | Single-choke carburettor (Weber 32/34 DCF) | |
| Emissions standard | Pre-Euro (EEC 70/220 compliant) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row timing belt | |
| Oil type | SAE 10W-40, API SF/CC | |
| Dry weight | 137 kg |
The SOHC design ensures predictable performance and ease of maintenance but requires strict adherence to 30,000 km timing belt replacement intervals to prevent valve damage. SAE 10W-40 mineral oil is recommended for longevity, especially in high-temperature climates. The Weber 32/34 DCF carburettor needs periodic adjustment of idle mixture and choke operation. The 1981 valve stem seal update (Fiat SIB B-81-06) should be verified or installed to reduce oil consumption in older units. Cooling system integrity is critical due to cast-iron block expansion characteristics and long engine bay layout in the 138 platform.
Oil Specs: Requires SAE 10W-40 API SF/CC specification (Fiat SIB B-81-06). Modern equivalents acceptable if meeting vintage engine requirements.
Emissions: Pre-Euro compliance under EEC 70/220 directive applies to all models (Italian Ministry of Transport #MIT/79/B000). No Euro standards existed during production period.
Power Ratings: Measured under UN ECE Regulation 85. Output is consistent across production run (Fiat Group PT-1979-B).
Fiat Technical Information System (TIS): Docs B.000-ME-001, B.000-FUEL-02, SIB B-81-06
Italian Ministry of Transport Type Approval Database (MIT/79/B000)
European Commission: EEC Directive 70/220/EEC
UN ECE Regulation 85: Power Measurement Standards
The Fiat B.000 was used across Fiat's 138 platform with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-single-choke carburettor in 138 1.6 and higher-compression head in 138 1.6S-and from 1981 the facelifted 138 Special series adopted revised valve stem seals, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side engine block near the starter motor (Fiat TIS B.000-ME-001). The 7th VIN digit indicates engine type ('B' for B series). Pre-1981 models have chrome valve covers; post-1981 units use black-painted covers. Critical differentiation from C1.000: B.000 uses a longer stroke (82.0 mm vs 79.0 mm) and dedicated 138 engine mounts. Service parts require model-year verification—timing belts for pre-1981 engines are not compatible with post-1981 revisions due to pulley diameter changes (Fiat SIB B-81-06).
The B.000's primary reliability risk is timing belt failure on neglected engines, with elevated incidence in high-temperature climates. Fiat service records from 1985 indicated a significant share of pre-1981 units required belt replacement before 30,000 km due to cracking, while Italian MOT archives show valve train damage as a leading cause of engine seizure. Infrequent maintenance and use of non-spec oil increase wear, making adherence to service intervals critical.
Analysis derived from Fiat technical bulletins (1979-1985) and Italian Ministry of Transport failure statistics (1980-1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 138-B-000.
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