The Fiat 100 G.002 is a 1,297 cc, inline — four naturally aspirated petrol engine produced between 1972 and 1985. It features a single overhead camshaft (SOHC), 8 — valve configuration, and carbureted fuel delivery, delivering reliable performance for compact city driving. In standard tune, it produced 51 kW (69 PS) at 6,000 rpm, with peak torque of 102 Nm available at 3,500 rpm.
Fitted to the Fiat 128, 128 Coupé, and 128 Familiare, the 100 G.002 was engineered as a front — moun…
Production years 1972–1985 meet Euro 0 and early Euro I standards (VCA UK Type Approval #VCA/FIAT/1287).
The Fiat 100 G.002 is a 1,297 cc inline-four naturally aspirated petrol engine designed for compact front-wheel-drive applications (1972–1985). It features a transverse mounting configuration, SOHC valvetrain, and carburetor-based fuel system to deliver dependable performance and ease of service. Engineered for urban and regional use, it balances economy with mechanical robustness.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,297 cc | |
Fuel type | Petrol (Unleaded or Leaded, 95 RON min) | |
Configuration | Inline-4, SOHC, 8-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 76.0 mm × 71.5 mm | |
Power output | 51 kW (69 PS) @ 6,000 rpm | |
Torque | 102 Nm @ 3,500 rpm | |
Fuel system | Weber 32 IDF twin-choke carburetor | |
Emissions standard | Euro 0 / Early Euro I | |
Compression ratio | 9.2:1 | |
Cooling system | Liquid-cooled, single-circuit | |
Turbocharger | None | |
Timing system | Single-row toothed belt (front-mounted) | |
Oil type | Fiat 10W-40 (Selenia), API SF | |
Dry weight | 118 kg |
The Fiat 100 G.002 was used across Fiat's front-wheel-drive platforms with transverse mounting and no licensed applications. This engine received minor calibration updates between the 128 Berlina and Familiare models, and from 1978 the introduction of hardened camshafts created interchange limits. All adaptations are documented in OEM technical bulletins.
The 100 G.002's primary reliability risk is camshaft wear under poor lubrication conditions, with elevated incidence in high-mileage or poorly maintained vehicles. Internal Fiat service reports from 1980 noted a subset of pre-1978 units requiring camshaft replacement before 100,000 km when service intervals were extended, while VCA field data confirms carburetor linkage wear in high-humidity environments. Extended idling and low-octane fuel increase stress on ignition and fuel systems, making service interval adherence and fuel quality critical.
Analysis derived from Fiat technical bulletins (1972–1985) and UK DVSA failure statistics (1980–2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The 100 G.002 is a mechanically simple and robust engine when maintained properly. Pre-1978 units have shown susceptibility to camshaft wear if oil changes are delayed. Later revisions (1978+) feature improved metallurgy and lubrication. Regular oil changes with Fiat 10W-40 and adherence to timing belt schedules are essential for long-term reliability.
Key issues include camshaft lobe wear (especially pre-1978), timing belt failure, carburetor wear, and distributor bushing degradation. These are documented in Fiat service bulletins and field reports. Proper operation and maintenance significantly reduce occurrence.
The 100 G.002 powers the Fiat 128 Berlina (1972–1984), 128 Coupé (1974–1980), and 128 Familiare (1975–1985). It is not used in rear-engined or commercial models. The engine features carbureted fuel delivery and SOHC valvetrain. It was succeeded by the 105-series OHV engine in later small Fiats.
Yes, within limits. Performance camshafts, high-flow exhaust, and tuned carburetors (e.g., Weber 40 IDF) can yield +15–25 kW. However, exceeding factory limits risks valve float and cam wear. Always use 95+ RON fuel when modified. Periodic valve adjustment is critical with performance parts.
Official combined consumption is ~8.2 L/100km (~34.5 mpg UK) for the 128 Berlina. Real-world usage varies—urban driving may reach 10.0 L/100km (~28.3 mpg), while highway cruising can achieve ~6.8 L/100km (~41.5 mpg). The lightweight design and modest displacement contribute to efficient operation.
Yes. The 100 G.002 is an interference engine. If the timing belt fails or skips, piston-to-valve contact will occur, resulting in catastrophic internal damage. The front-mounted belt system requires correct tension and lubrication. Any valvetrain noise must be investigated immediately.
Fiat specifies 10W-40 mineral oil meeting Fiat/Selenia standards (API SF). Oil must be changed every 15,000 km or annually. Using incorrect oil can lead to camshaft wear, bearing failure, and oil pump damage. Always use OEM-approved lubricants or equivalents with ZDDP for flat-tappet protection.
Comprehensive technical documentation and regulatory references
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Regulation (EC) No 715/2007
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