Headlamps

The first electrically powered headlamp was known as the SS49 with a curious bayonet fitting rim, the glass and reflector were separate parts and the shell contained a fancy ammeter and even fancier switch with manual charging control. The ammeter was placed at the rear of the shell making it rather difficult to see and in 1930 a variation arrived, the H52, which had the ammeter positioned on the top of the shell where it could be seen, the switch taking the position of the ammeter. In 1934 it was replaced in turn by an 8” headlamp, which was available with a flat or domed glass and the switch and ammeter were now in a separate instrument panel on the shell. This was in use up to the war when the headlamp was changed to a more economical 6″ (with blackout masks it did not really matter what was under the hood). 7″ headlamps, still with separate glass and reflectors were introduced in 1949, as supplies became available. In 1951 the separate glass and reflector was replaced by a combined unit with a new type of bulb known as the British Pre-Focus or BPF which meant an end to focusing the bulb whenever it was changed. We call the earlier bulb the pre-pre-focus If you have a 1934-1949 headlamp it is important to identify whether the glass should be flat or domed as this affects the shell, rim and catch as well as the glass and these parts are not interchangeable. Ariel always fitted headlamps with flat glasses up to the end of the war but this did not prevent a domed glass headlamp being requested by the first owner. The model type will be stamped into the base of the shell near the catch. The lamps with dome shape glasses use a cast alloy clip, whilst the flat glass type uses a sheet steel clip, Usually! Lucas headlamp model codes are: – M= dome glass; D=flat glass; U=instrument panel; 42=6”; 142=7 ½” (8”); 575=5 ¾”; 700=7”.

Headlamp Assemblies and Application

Use this list to find out which headlamp should be fitted or use the description to find out what is actually fitted. Complete headlamps are listed under the model number in the price list, where available. Some are made India and are very good copies with the exception of the ammeter, which is not very good. Others are made by us and assembled using parts from a variety of sources. The 1951-55 Square Four headlamp is listed as different by Lucas but the only difference is the ‘red spot’ ammeter, which is not currently available so we will supply a standard headlamp instead. For available parts see the table below using the ‘Ref No.’.

The parts listed below are for the original headlamps, most replacement headlamps use later fittings and some of the parts below will be later designs but will fit and do the same job as the original. For details of switches see section 40D. Please read the notes at the bottom of the table.

NOTES N/A       Not available —         Not fitted 4           Instrument panel – complete with switch and a cheap ammeter, not suitable for 1949 SQ4 5 & 6    Screw for instrument panel – these seem to vary, some at least due to damage, usually there is a threaded bush in the shell but often a nut has to used as the bush is missing. 7           Medallion – 1950 KH and SQ4 only, 7/8” diameter 8 & 9    Ammeter – not correct for 1949-58 SQ4 as there is no charging light but will still work 16         Light unit 515140 – replaces the original glass and reflector and uses BPF bulbs (312 or 414) and holder (554 602), which are not included. Although this unit is for flat glass headlamps it is slightly domed and does fit the original rim and shell, the glass has a large diamond pattern as per the original domed glasses. 16         Light unit 553147 – uses BPF bulb, not supplied, order 312 or 414. 16         Light unit 555309A – uses modern 12 volt P43T bulbs, fittings are included but bulbs are not; order 472 from bulb section. 20         Main bulb holder – some early SS700 units use a 504801 bulb holder which was obsolete by 1957 and still is not available, if one of these is needed a later light unit will have to be fitted. 28         For the switch