The History of the SU Carburetter: Part 2 1945-2018

THE SECOND WORLD WAR

The Second World War increased SU operations significantly; by the outbreak of hostilities the works employed some 700 people, an increase of 300 in about 6 months, supplying all the aero-carburetters for Rolls Royce Merlin, Vulture and Peregrine as well as Napier for their Sabre and Dagger engines. The company was also manufacturing its fuel pumps for military applications.

The dangers of this one factory supplying the entire aero-carburetter requirements for the RAF Spitfires, Hurricanes and bombers was realised in late 1939 and it was decided to set up a duplicate plant in the Riley works in Coventry.

Air raids in November 1940 caused damage to the works. In the first air raid the factory was set on fire, but was contained and extinguished by the works’s fire brigade, and although three high explosives scored direct hits, two in the machine shop, the carburetter production line survived intact.

In the second raid no bombs fell on the SU works itself but girders and other debris from surrounding buildings came through the roof and the Ministry for Aircraft Production decided to evacuate the factory. After only twelve hours notice the first RAF trucks arrived to remove the plant to a modern, newly constructed factory at Highlands Road, Shirley, recently requisitioned from the Co-op. Production continued non-stop during the move, however any gaps were being filled by the Riley shadow factory.

After the move the number of workers quickly rose to 1,500. The weekly output of carburetters was doubled after Dunkirk to 200 a week, with a normal working day of 8am to 7pm. This working day was voluntarily stretched quite often with workers sometimes sleeping on the floor next to their machines.

A second shadow factory was set up in the Wharf Valley in Yorkshire in 1941, in the village of Barwell. A boot factory requistioned for the purpose. As well as the SU, this factory made the Rolls Royce Bendix Stromberg type carburetter.

In 1942 the petrol injection pump was developed for the aero-engines, first fitted on Mosquito aircraft. Two SU technical staff had taken out a patent in 1939 but the firm could not get anyone interested at the time. After three years of neglect, the SU design was adopted and the new British petrol injection pump came into general use in the last year of the war. It was later built under licence by an American company and called The Simmonds lnjector Pump.

GROWTH AND DECLINE

In 1945 the production of carburetters and pumps for motor vehicles was resumed and moved to Erdington, Birmingham in July 1947.

The “Skinner” connection was finally severed in this year when Morris (Lord Nuffield) called a meeting with Carl, now aged 65, along with eight other senior figures from various parts of the Nuffield Empire and announced their retirement. So ended a career dedicated to the development of his brother’s ingenious invention.

The following year saw the introduction of aluminium die castings replacing zinc and brass, a direct result of experience gained during the war years making good use of plentiful supplies of aluminium left over from aircraft production

After the war, developments and new introductions came almost on a yearly basis. In 1950 dustproofing was introduced. In 1952 the formation on the British Motor Corporation widened the market for SU carburetters and pumps further, and in 1954 were introduced both the part throttle weakener for single car applications on 6-cyl engines (e.g Rover P4) and the HD type carburetter.

1958, the year Carl Skinner died, saw the introduction of the HS type carburetter. 1962 the delrin float needle, and the following year the nylon float for HS carburetters. 1967 saw the development and marketing of a mechanical fuel pump and shortly after an Automatic Enrichment Device (AED).

In 1969 the spring loaded metering needle and throttle overrun valve were introduced, in 1971 jet temperature compensation on HS8 carburetters, and in 1972 the HIF type. Jet temperature compensation was expanded to HS4 and HS6 carburetters in 1975; the following year the ball bearing suction chamber was introduced and the part throttle weakener further developed.

By 1976 SU’s position, that of a small plant in a rapidly declining car manufacturer known as British Leyland Motor Holdings, changed once again when it became part of a division of service and parts known as SU/Butec.

In 1982 SU introduced the HlF44E carburetter; which had electronic control of the cold start function, idle speed and overrun fuel cut-off. With the demise of SU/Butec a few years later, SU lost its identity to become Austin Rover Fuel Systems, the beginning of a long period of drift and decline with SU parts becoming more and more difficult to service.

In 1988 the company was acquired by the Hoburn Eaton Group who themselves were acquired by a large USA based multinational Echlin Corporation eighteen months later. Echlin itself was acquired by the Dana Corporation in 1998 and the company traded under the name Dana SU Automotive.

BURLEN FUEL SYSTEMS LTD.

By the early eighties SU was seriously considering ceasing production of the HS pairs (MGB Midget, Spitfire etc), but they were persuaded to keep tooling operational by Burlen Services.

Burlen Services was formed in 1971 and first became involved with SU carburetters in the fuel crisis of 1974, when they were first appointed as agents. There followed a long period of co-operation, to the mutual benefit of both companies, culminating in a joint venture to rescue the defunct Solex UK production in 1985.

The company changed its name to Burlen Fuel Systems in 1986.

Burlen Fuel Systems were responsible for the re-emergence of the SU brand after many years of neglect. They upgraded the image with the new SU blue livery and first promoted the product at Autoequip in 1987, followed quickly by several other UK shows and the prestigious 1988 AutoMechanika in Germany.

1994 saw the end of an era of carburetter production for the great marques of motor manufacturing when SU ceased original equipment carb production.

On 16th August 1994 the final units, designated HIF and KIE were produced, direct descendants of the original design by the Skinner brothers, the longest running UK carburetter in production.

However in June 1996 Burlen Fuel Systems made a commitment to producing aftermarket SU product for years to come. In 1997 Burlen acquired “The SU Carburetter Co Ltd” which had been wound up the previous year.

The following years represented a continual period of product development, including electronic switching for fuel pumps, expansion through cataloging, world wide sales promotion and investment in new tooling to support the classic car market. Burlen Fuel Systems are also responsible for producing the well known service and rebuild kits associated with SU carburetters and pumps.

November 2001 saw the official closure of what once was the SU factory and Burlen Fuel Systems became the world’s sole manufacturer of genuine, new SU products.

RECENT DEVELOPMENTS

2015 saw the company name change from Burlen Fuel Systems to Burlen Ltd, still operating out of the factory in Salisbury. Over the years Burlen’s commitment has seen increased investment for new tooling to extend the SU range in production. This investment has also seen the introduction of a CNC machine shop to improve quality and increase production in house.

Burlen Ltd is dedicated to ensuring the long term supply of genuine SU parts for the classic car market. All Burlen’s SU products are packaged using the SU logo as well as all our literature. This is your assurance of quality of product.

CARBURETTOR IDENTIFICATION

The carburettor identification is made by letter prefix which indicates the float type:

“H” introduced in 1937 in which the float bowl has an arm cast into its base, which mounts to the bottom of the carburetter with a hollow bolt or banjo fitting. Fuel passes through the arm into the carburetter body. The bolt attaches to the carburettor body just behind the main jet assembly. Click here to view a diagram and parts list for the H Type SU Carburetter.

“HD” introduced in 1954 with the float bowl mounted with its arm fastening directly below, and concentric with, the main jet. The arm has a flange that fastens with four screws to the bottom of the carburettor, and sealed with a rubber diaghragm integral with the main jet.

“HS” introduced in 1958 the float bowl can be rigidly or rubber mounted to the main body, fuel is transferred by an external flexible pipe to the jet. The jet moves down to richen the mixture for cold starting, when the “choke” linkage is pulled.

“HIF” introduced in 1982, the float bowl is horizontal and integral (hence the name) Horizontal Integral Float.

“HV” introdcued in 1929, “OM” and “KIF” types also exist but were less commonly employed.

The imperial sizes include: 1-1/8″, 1-1/4″, 1-1/2″, 1-3/4″, 1-7/8″, and 2″, although not every type (H, HD,HS, HIF) was offered in every size.