Hillman 20 8-cylinder
| Industry | Automotive |
|---|---|
| Founded | 1907 |
| Headquarters | United Kingdom |
| Products | Automobiles |
The Hillman Straight Eight and its follow-up model, the Hillman Vortic, were moderately priced executive vehicles of mid-size, manufactured by Hillman between 1929 and 1930. Marketed as the most affordable eight-cylinder option available, their production and sales volumes were significantly hindered by the economic downturn triggered by the Great Depression.
Although competitively priced, the Straight Eight experienced issues with engine bearing durability. The Vortic, essentially a rebranded version, introduced slight enhancements like a silent third gear but was mainly used to reduce surplus stock. Both variants remained on sale until 1932.
In April 1931, Hillman phased out the Straight Eight from its range and introduced six-cylinder alternatives: the (Wizard 65) and the (Wizard 75).
Hillman Straight Eight
Announced in September 1928 ahead of the 1929 Olympia Motor Show, no images or promotional materials appeared until mid-March 1929, with an in-depth description following in May. A two-door, four-seat Segrave fabric coupé powered by a Straight Eight engine was showcased at the 1928 Motor Show, though public details were limited.
Engine
The powertrain is a 2.6-liter inline eight-cylinder with a long stroke design, featuring a bore of 63 mm and a stroke length of 105 mm. The pistons are crafted from die-cast aluminium alloy. Overhead valves are actuated through pushrods and receive forced lubrication along with other engine components. Timing is chain-driven with assured oil delivery, and oil pressure is adjustable manually. Cooling is facilitated by an impeller that circulates water through a honeycomb radiator equipped with thermostatically controlled shutters.
The crankshaft incorporates a front-end vibration damper, and both it and the camshaft operate on five bearings each. The engine, single-plate dry clutch, and gearbox are integrated into a single unit mounted on four supports.
- Gearbox
The transmission offers four speeds with a gear lever positioned offside to the driver's right hand. It functions within an exposed gate featuring a reverse gear lockout.
Chassis
The chassis design closely mirrors that of Hillman’s 14-horsepower model.
- Suspension
Fitted with wire wheels, the suspension employs half-elliptical springs arranged splayed at the front and rear, with underhung springs at the back. Friction shock absorbers control movement on both axles.
- Brakes
Brake pedals operate independently from the frame structure. A handwheel located beneath the floorboards enables primary adjustment of fully enclosed drum brakes on all four wheels. The handbrake engages separate rear brake shoes adjustable via the lever’s top mechanism. Rear brakes utilize a single cable to ensure balanced application pressure; front brakes are actuated through pull-rods. Notably, a brake servo motor is integrated within the gearbox assembly—a distinctive feature uncommon for vehicles in this price category during that era.
- Steering
Steering is managed by Marles gear mounted on the engine block, complemented by an adjustable rake on the steering column.
Body
The bodywork includes safety glass resistant to shattering and headlamps with dipping reflectors. At the rear, there is a spare wire wheel alongside a folding luggage rack.
Trial
The Times conducted a test on a standard five-seat, four-door saloon with six lights, highlighting that its one-piece windscreen equipped with an electric wiper opens wide enough to ensure clear visibility during adverse weather conditions. The cabin was described as comfortable yet somewhat narrow at the front. Rear door access was convenient, although sliding forward the front seats improved ease of entry further. Side windows lowered completely. The vehicle achieved a top speed of . Steering feedback was praised as "delightful."
Unreliable
The Straight Eight engine became known for its lack of dependability and slow performance.
Hillman Vortic 8
Enhancements in engine output were achieved through the introduction of a patented turbo combustion cylinder head alongside specially designed connecting rods. The crankshaft received harmonic balancing improvements. The transmission featured a silent third gear, referred to as the Traffic top. Both the speed and handbrake levers were positioned centrally, while a tail lamp was included as standard equipment. The front seat offered an adjustment range of eight inches. Quick-action winders operated the side windows, with the driver’s window controlled by a lever. A single windscreen wiper came standard, with the option to add a second. The steering wheel incorporated controls for the horn, headlamp dimmer, spark timing, and throttle. Wire wheels remained standard, and the spare wheel was stored behind the petrol tank, situated in front of the folding luggage rack.
According to The Times, the updated saloon approached nearly in top gear and exhibited enhanced engine responsiveness compared to the previous Straight Eight model. While the final drive produced a humming noise, the gearbox functioned quietly. The braking system required only light pressure and provided sufficient assistance when reversing.
One year later, additional modifications included securing the Marles steering box directly to the frame rather than the engine block, mounting the engine clutch and gearbox assembly on rubber mounts at the front, relocating the handbrake lever onto the gearbox casing, and fitting hydraulic shock absorbers at the rear. The Times observed that the single-piece windscreen could open wider to improve visibility during adverse weather conditions and recommended that installing hydraulic shock absorbers all around might enhance ride comfort. Driving remained straightforward and comfortable at speeds up to , although it "required some effort to reach full performance."
External links
- Hillman Straight Eight likely Segrave fabric sports saloon