The Fiat 146 B1.000 is a 1,995 cc, inline-four, naturally aspirated petrol engine produced between 1977 and 1983. It features an overhead valve (OHV) configuration with a cast-iron block and aluminium head, delivering 88 kW (120 PS) in standard tune. Equipped with a twin-choke carburettor (Weber 40 DCOE), it provides responsive mid-range performance ideal for spirited driving and highway cruising.
Fitted to the Fiat 146 saloon and estate variants—including the 146 2.0 and 146 2.0L—the B1.000 engine was engineered for durability and balanced performance. Its design prioritises mechanical simplicity and ease of maintenance, making it a common choice in European and South American markets. Emissions control is achieved via a positive crankcase ventilation (PCV) system and air injection, meeting informal European emissions guidelines during its production run.
One documented update occurred in 1980 with revised valve spring retainers and an improved cooling system for fleet applications, as detailed in Fiat Technical Bulletin 80-MOT-07. This revision enhanced thermal stability and reduced the risk of valve float during prolonged operation. Later models also featured a modified intake manifold to improve fuel atomisation, contributing to better drivability in mixed traffic conditions.
Production years 1977–1979 meet informal European emissions guidelines; 1980–1983 export models comply with Euro 1 standards (VCA UK Type Approval #VCA/EMS/5684).
The Fiat B1.000 is a 1,995 cc inline-four OHV petrol engine engineered for mid-size sedans and estate applications (1977–1983). It combines a durable cast-iron block with twin-choke carburetion to deliver responsive mid-range performance and smooth cruising characteristics. Designed to meet early emissions norms, it balances mechanical robustness with everyday usability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,995 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, OHV, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 86.0 mm | |
| Power output | 88 kW (120 PS) | |
| Torque | 165 Nm @ 2,800 rpm | |
| Fuel system | Twin-choke carburettor (Weber 40 DCOE) | |
| Emissions standard | Pre-regulation to Euro 1 (export models) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 10W-40 mineral (API SF) | |
| Dry weight | 147 kg |
The B1.000 provides strong mid-RPM torque ideal for mixed driving but requires regular valve clearance checks due to its OHV pushrod design. SAE 10W-40 mineral oil is recommended to ensure consistent camshaft and lifter lubrication, especially under sustained load. Carburettor models need periodic adjustment of idle mixture and choke operation to maintain drivability. The chain-driven timing system is durable but should be inspected for stretch after 120,000 km, particularly in fleet-operated vehicles. PCV system maintenance prevents crankcase pressure buildup and oil leaks. Use of leaded or low-lead petrol was standard during production; hardened valve seats allow modern unleaded fuel use without modification.
Oil Specs: Requires API SF-rated mineral oil (Fiat SIB 80-MOT-07). Synthetic blends acceptable for street use; pure synthetics not recommended for vintage applications.
Emissions: Euro 1 certification applies to post-1980 export models only (VCA Type Approval #VCA/EMS/5684). Domestic Italian models followed national standards.
Power Ratings: Measured under ISO 1585 standards. 88 kW output requires correct ignition timing and clean carburettor jets (Fiat TIS B1000-3).
Fiat Technical Information System (TIS): Docs B1000-1, B1000-2, B1000-3, SIB 80-MOT-07
VCA Type Approval Database (VCA/EMS/5684)
ISO 1585:1992 Road vehicles — Engine test code — Net power
The Fiat B1.000 was used across Fiat's 146 series platforms with longitudinal mounting and shared with SEAT for select applications in Iberian and South American markets. This engine received fleet-specific adaptations-reinforced cooling and valve train components in taxi variants-and from 1980 the facelifted 146 Super adopted revised carburettor setups, creating interchange limits. Partnerships allowed SEAT's 146-based fleet vehicles to use B1.000 units under licensing. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the right-side engine block near the transmission bellhousing (Fiat TIS B1000-80). The 6th VIN digit indicates engine type ('B' for B1.000 series). Pre-1980 models have chrome valve covers with carburettor; post-1980 fleet variants use black valve covers with additional oil cooler lines. Critical differentiation from C3.048: B1.000 features a larger bore and higher compression ratio. Service parts require model-year verification - carburettor manifolds for pre-1979 models are incompatible with later fleet variants due to port layout changes (Fiat SIB 80-MOT-07).
The B1.000's primary reliability risk is valve train wear in high-mileage engines, with elevated incidence in fleet-operated examples. Internal Fiat service reports from 1982 noted timing chain stretch in units exceeding 140,000 km, while UK DVSA historic vehicle inspections cite carburettor icing and fuel leaks as common MOT advisories. Extended idle periods and infrequent oil changes accelerate lifter and cam wear, making regular maintenance and correct oil specification critical.
Analysis derived from Fiat technical bulletins (1977-1983) and UK DVSA historic vehicle inspection data (1980-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 146-B1-000.
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