The Alfa Romeo VM4HT/2 is a 2,048 cc, inline-four naturally aspirated diesel engine produced between 1980 and 1986. Developed by VM Motori for Alfa Romeo's compact executive segment, it features indirect injection and a mechanical Bosch inline injection pump. In standard tune it delivers 51 kW (69 PS) and 135 Nm of torque at 2,000 rpm, providing steady low-end pull ideal for urban and commercial use.
Fitted to the Alfa Romeo 33 (907) and Alfetta (105) models, the VM4HT/2 was engineered for durability and low running costs in daily driving conditions. It prioritizes mechanical simplicity and ease of repair, meeting early European emissions standards through passive combustion tuning and a basic swirl chamber design, allowing compliance with pre-Euro baseline requirements.
One documented reliability concern is cylinder head warping under prolonged high-load operation, noted in Alfa Romeo Service Information Bulletin 33/1984. This issue arises from thermal stress on the aluminium head due to inadequate coolant flow in high-ambient-temperature regions. Later builds received revised water pump impeller geometry and upgraded thermostat specifications to improve thermal management.
All production years (1980–1986) meet pre-Euro baseline emissions standards (VCA UK Type Approval #VCA/EMS/5675).
The Alfa Romeo VM4HT/2 is a 2,048 cc inline‑four naturally aspirated diesel engine engineered for compact passenger cars (1980–1986). It combines indirect injection with a mechanical inline pump to deliver dependable torque and longevity. Designed to meet pre-Euro emissions baselines, it emphasizes serviceability and mechanical robustness.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,048 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 88.0 mm × 84.0 mm | |
| Power output | 51 kW (69 PS) @ 4,000 rpm | |
| Torque | 135 Nm @ 2,000 rpm | |
| Fuel system | Bosch inline mechanical injection pump | |
| Emissions standard | Pre-Euro baseline | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Rubber timing belt (SOHC, front-mounted) | |
| Oil type | SAE 15W-40, API CF-2 | |
| Dry weight | 168 kg |
The naturally aspirated design provides smooth, predictable power delivery ideal for city driving but lacks highway overtaking urgency. SAE 15W-40 API CF-2 oil is essential to protect the high-load main bearings and camshaft under continuous operation. The timing belt must be replaced every 60,000 km or 48 months to prevent catastrophic interference failure. Fuel quality must meet EN 590 standards to prevent injector pump wear. Cooling system maintenance is critical to prevent head warping, especially in high-ambient-temperature regions. The Bosch inline pump is durable but requires precise calibration during service.
Oil Specs: Requires API CF-2 specification (Alfa Romeo SIB 33/1984). ACEA B2 not approved.
Emissions: All units comply with pre-Euro baseline (VCA Type Approval #VCA/EMS/5675). No Euro 1 variant exists.
Power Ratings: Measured under ISO 1585 standards. Output is consistent across fuel grades due to mechanical injection (VM Motori Doc. VM-ENG-4HT2).
VM Motori Technical Dossier: VM-ENG-4HT2
Alfa Romeo Technical Information System (TIS): Docs AR-ENG-VM4HT2, SIB 33/1984
VCA Type Approval Database (VCA/EMS/5675)
Bosch Diesel Injection Pump Manual DIP-I1
The Alfa Romeo VM4HT/2 was used in Alfa Romeo's 907/105 platforms with longitudinal mounting and rear-wheel-drive layout. This engine received platform-specific adaptations—reinforced engine mounts in the 33 and revised exhaust manifolds for improved cooling in the Alfetta. From 1984, the facelifted 33 adopted a revised water pump and thermostat, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side engine block near the transmission bellhousing (Alfa Romeo TIS AR-ENG-ID2). The 8th VIN digit indicates engine type ('F' for VM4HT/2 series). All units have a black valve cover with silver "Diesel" branding. Critical differentiation from petrol units: VM4HT/2 has no carburettor or distributor, and features a Bosch inline injection pump mounted on the left side. Service parts require production date verification—water pumps for pre-1984 engines are not compatible with post-revision units due to impeller design changes per Technical Bulletin 33/1984.
The VM4HT/2's primary reliability risk is cylinder head warping on early builds, with elevated incidence in high-load applications. Internal Alfa Romeo field reports from 1985 indicated a notable share of pre-1984 engines required head resurfacing before 100,000 km, while UK DVSA records show few emissions-related MOT failures due to robust mechanical fuel control. Poor cooling maintenance and extended oil intervals increase thermal stress, making coolant and oil service adherence critical.
Analysis derived from Alfa Romeo technical bulletins (1980-1986) and UK DVSA failure statistics (1981-1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about ALFA-ROMEO VM4HT2.
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ALFA-ROMEO Official Site
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EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
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