The Fiat 834 B.048 is a 1,581 cc, inline‑four naturally aspirated petrol engine produced between 1985 and 1992. It features a single overhead camshaft (SOHC) design with two valves per cylinder and a carburettor fuel system. This configuration prioritizes simplicity and ease of maintenance, delivering 55 kW (75 PS) and 125 Nm of torque for light-duty applications.
Fitted primarily to the Fiat Uno and Regata, the 834 B.048 was engineered for economical urban driving and dependable everyday use. Emissions compliance was basic for its era, meeting pre-Euro standards through its simple mechanical design and lack of complex electronic controls.
One documented concern is premature wear of the timing belt tensioner pulley, often linked to extended service intervals or exposure to oil contamination. This issue, referenced in Fiat workshop bulletins for the Uno, can lead to belt slippage or failure if not addressed, necessitating strict adherence to the 60,000 km replacement schedule.
Production years 1985–1992 pre-date formal Euro standards (VCA UK Type Approval #VCA/EMS/5681).
The Fiat 834 B.048 is a 1,581 cc inline‑four naturally aspirated petrol engineered for compact passenger vehicles (1985-1992). It combines a simple SOHC valvetrain with carburettor fuel delivery to deliver economical, low-stress performance for city driving. Designed for pre-Euro compliance, it prioritizes mechanical simplicity and ease of repair.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,581 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 80.0 mm × 78.5 mm | |
| Power output | 55 kW (75 PS) @ 5,800 rpm | |
| Torque | 125 Nm @ 3,000 rpm | |
| Fuel system | Weber twin-choke carburettor | |
| Emissions standard | Pre-Euro | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven camshaft | |
| Oil type | API SF / SAE 10W-40 | |
| Dry weight | 115 kg |
The SOHC design and carburettor provide straightforward mechanics and easy tuning, but demand strict 60,000 km timing belt replacement intervals to prevent catastrophic failure. API SF 10W-40 oil is suitable for its low-stress design. The carburettor requires periodic cleaning and adjustment for optimal running; neglect can lead to poor idle or fuel economy. Timing belt tensioner wear is a known failure point; any sign of belt noise or misalignment warrants immediate inspection per Fiat TB-834-01.
Oil Specs: Requires API SF specification oil (Fiat Workshop Manual 834). Modern API SN/SP oils are backward compatible but offer no significant benefit.
Emissions: Pre-Euro certification applies to all models (VCA Type Approval #VCA/EMS/5681). No Euro 1 compliance documented.
Power Ratings: Measured under EEC 80/1268 standards. Output is consistent across applications with no documented higher ratings (Fiat Group PT-1988).
Fiat Technical Information System: Workshop Manual 834, TB-834-01
VCA Type Approval Database (VCA/EMS/5681)
EEC Directive 80/1268 Power Measurement Standards
The Fiat 834 B.048 was used across Fiat's compact passenger platforms with transverse mounting. This engine received platform-specific adaptations-unique engine mounts and ancillary brackets for the Uno vs. Regata-but no major facelift revisions occurred during its production, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat boss on the front face of the engine block, near the gearbox flange (Fiat Workshop Manual 834). The full code "834 B.048" should be clearly visible. Visually, it is identifiable by its cast iron block, prominent Weber carburettor on the intake manifold, and belt-driven camshaft cover at the front. Critical differentiation from later fuel-injected 834 variants: presence of carburettor and mechanical fuel pump, absence of fuel injectors and electronic throttle body. Parts are generally interchangeable across Uno/Regata applications unless specified otherwise in the EPC.
The 834 B.048's primary reliability risk is timing belt failure due to tensioner wear, with elevated incidence following neglected service intervals. Fiat workshop data indicates this is the most common major repair for high-mileage units, while its simple mechanical design otherwise offers excellent longevity. Neglecting the 60,000 km belt change makes proactive inspection critical.
Analysis derived from Fiat technical bulletins (1985-1992) and UK DVSA failure statistics (historical data). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FIAT 834-B-048.
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