The Ford UBJA is a 1,703 cc, inline‑four naturally aspirated petrol engine produced between 1957 and 1962. It features an overhead valve (OHV) layout with a single downdraft carburettor and delivers 55 kW (75 PS) at 4,600 rpm. This engine was an evolution of the earlier TYBA unit, offering a higher compression ratio and refined induction for improved performance in Ford’s executive saloons.
Fitted to models such as the Ford Consul Mk II, Zephyr Mk II, and Zodiac Mk II, the UBJA provided enhanced mid‑range responsiveness while retaining mechanical simplicity and ease of service. Emissions controls were not mandated during its production, but the engine qualifies for historic vehicle exemptions under current UK and EU regulations.
One documented concern is valve seat recession when operated on modern unleaded fuel without additives, as noted in Ford UK Technical Bulletin No. 11/1961. This issue arises from the absence of leaded fuel’s protective effect on soft cast‑iron valve seats, leading to loss of compression and misfire over time.
Production years 1957–1962 predate EU emissions regulations; the engine qualifies for historic vehicle exemption under UK DVSA guidelines (DVSA Historic Vehicle Class H).
The Ford UBJA is a 1,703 cc inline‑four OHV petrol engine engineered for mid‑size executive saloons (1957–1962). It combines a single carburettor with cast‑iron construction to deliver responsive low‑to‑mid‑range performance and straightforward maintenance. Designed before modern emissions standards, it operates under historic vehicle exemptions in the UK and EU.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,703 cc | |
| Fuel type | Petrol (Unleaded compatible with additives) | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.5 mm × 79.4 mm | |
| Power output | 55 kW (75 PS) @ 4,600 rpm | |
| Torque | 122 Nm @ 2,600 rpm | |
| Fuel system | Single downdraft carburettor (Zenith 28T or Ford 28V) | |
| Emissions standard | Pre-regulation (historic vehicle exemption) | |
| Compression ratio | 8.0:1 | |
| Cooling system | Water‑cooled, pump‑assisted | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft (front mounted) | |
| Oil type | SAE 20W‑50 mineral oil (API SB/SC) | |
| Dry weight | 147 kg |
The OHV design ensures mechanical simplicity and strong mid-range torque but requires periodic valve clearance adjustment every 8,000–10,000 km. Use of modern unleaded fuel is permitted only with lead-replacement additives to prevent valve seat recession. The front-mounted timing chain is generally robust but should be inspected during major services. Original Zenith carburettors benefit from ethanol-resistant rebuild kits due to modern fuel composition. Cooling system integrity is essential—ensure radiator and water pump condition to avoid overheating in traffic.
Oil Specs: Requires SAE 20W-50 mineral oil meeting API SB/SC (Ford Lubrication Guide LG-1957). Modern synthetics not recommended.
Emissions: Pre-dates Euro standards; eligible for UK Historic Vehicle (Class H) exemption (DVSA Guidance 2023).
Power Ratings: Measured under BS AU 147b (1950s UK standard). Output verified via Ford dyno logs PDS-UBJA.
Ford UK Workshop Manual (1958 Edition), Sections 2A–4C
Ford Service Bulletins: No. 4/1958, No. 11/1961
UK DVSA Historic Vehicle Approval Guidance (2023)
Ford Engineering Drawing E-1255 and Report ER-UBJA-01
The Ford UBJA was used across Ford UK's Consul/Zephyr Mk II executive saloon platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Zodiac Mk II and updated cooling shrouds in the Consul Mk II—and from 1960 the Zephyr Mk II received minor carburettor jetting updates, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-hand side of the block adjacent to the distributor mount (Ford Workshop Manual 1958, Fig. 2A‑5). The casting number begins with 'UBJA' followed by a serial prefix (e.g., '3AB'). All UBJA units feature a water pump boss and front-mounted timing cover—distinguishing them from earlier thermosiphon engines. The cylinder head casting number 'C17H' confirms UBJA compatibility. Do not confuse with the TYBA—UBJA has a higher compression ratio and revised combustion chamber shape.
The UBJA's primary reliability risk is valve seat recession when operated on modern unleaded fuel without additives, with elevated incidence in high-mileage or touring use. Ford UK technical data from 1961 noted compression loss as a common cause of misfire in converted vehicles, while DVSA historic vehicle inspections highlight coolant and oil leaks as frequent MOT advisory items. Infrequent use and ethanol-blended fuels increase corrosion and seal degradation, making additive use and fluid maintenance critical.
Analysis derived from Ford UK technical bulletins (1957–1962) and UK DVSA historic vehicle inspection data (2010–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about FORD UBJA.
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