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-mounted, transverse powerplant emphasizing mechanical simplicity and ease of maintenance. It formed the backbone of Fiat’s small family car lineup during the 1970s and early 1980s, meeting early European emissions standards through basic emission control systems, including an evaporative canister and exhaust gas recirculation (EGR) on later models.
One documented reliability concern involves premature camshaft wear, particularly in vehicles with extended oil change intervals. This issue was addressed in Fiat Service Information Bulletin SIB 500.01.003 (1978), which recommended revised lubrication protocols and inspection intervals. Later production units (post-1978) incorporated hardened cam lobes and updated oil pump designs to improve longevity.
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 carbureted SOHC design delivers predictable performance ideal for city driving but demands strict adherence to 15,000 km or annual oil changes using Fiat 10W-40 to prevent camshaft lobe wear. Timing belt replacement is required every 60,000 km or 5 years to avoid catastrophic failure. Fuel quality (minimum 95 RON) ensures stable idle and throttle response. The front-mounted belt system is accessible but requires tension verification during service. Post-1978 revisions include hardened camshafts and improved oil flow per SIB 500.01.003, significantly enhancing durability in well-maintained examples.
Oil Specs: Requires Fiat 10W-40 (Selenia) specification (Fiat SIB 500.01.003). Compatible with API SF standards.
Emissions: Euro 0 applies to early 1972–1976 models (VCA/FIAT/1287). Euro I compliance confirmed for 1977–1985 production.
Power Ratings: Measured under ECE R85 standards. Output consistent across 128 variants per Fiat TIS FT-1282.
Fiat Technical Information System (TIS): Docs FT-1282, FT-1284, FT-1285, SIB 500.01.003
VCA Type Approval Database (VCA/FIAT/1287)
European Commission Regulation (EEC) No 168/87
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.
Locate the engine serial number stamped on the right-side engine block near the transmission mating flange (Fiat TIS FT-1280). The 7th VIN digit indicates engine type ('B' for 100 G.002 series). 128 Berlina (1972–1977) models feature a chrome air cleaner cover; post-1978 units have a black plastic cover with emissions label. Critical differentiation: All 100 G.002 engines are interference designs with front-mounted timing belts. Service parts require model and production date verification—camshafts for pre-1978 units are not compatible with post-1978 engines due to metallurgy upgrade (Fiat SIB 500.01.003).
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.
Find answers to most commonly asked questions about FIAT 100-G-002.
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