• Combustion Chambers:- Arthur Freeman-Sanders, who joined Fowlers in 1934 designed the range of Fowler petrol engines and in doing so developed the most important feature of the engine - the Swirl Combustion Chamber which was also employed in the diesel range of engines known as the 'Two Way Swirl' combustion chamber

Freeman-Sanders's speciality was combustion chamber design and his radical design ensured instantaneous combustion throughout the charge admitted to the cylinder. The swirl design promoted accelerated air movement within the combustion chamber resulting in a scattered flame which quickly spread resulting in full and complete combustion of the charge. This cylinder head design, combined with careful carburettor selection are the key factors which has resulted in many people commenting on the fuel efficiency of the smaller Fowler petrol engines, compared to similar counterparts. (click the image to enlarge)

• Magnetos:- Two magnetos were used during the production run of Fowler engines, these were the Lucas N1 and the familiar Wico A series units. It seems that the Lucas magneto was most commonly used however engines can often bee seen with the Wico magneto as an alternative. In terms of what magneto was best, both were very good however the Wico unit usually survives better than the Lucas units as they are of a newer design. Most Fowler's with Lucas magnetos require a full magneto rebuild since the armature coil and condenser are usually open circuit. Follow the links below for more detailled magneto specifications, diagrams and parts lists. (several large images are present in these pages).

Lucas N type

Wico A type

It appears that the majority of magnetos were the Lucas product, however it is useful to know that the Wico A series can be used if a replacement is required. Twin cylinder versions of these magnetos were used for the multi-cylinder engines.

In general it appears that the Lucas N1 was the most commonly used magneto on the Fowler range, it is this magneto which is usually seen on the rallyfield. Unfortunately this magneto does suffer from deterioation with age, many Lucas N1's now require to be rewound and rebuilt. This is usually due to the coil windings going open circuit, insulation breaking down and problems with 'leaky' slip rings. A typical rebuild including replacement slipring for the Lucas N1 magneto will cost in the region of £90.00 from specialist magneto repairers.

• Carburettors:- Early Fowler PA engines utilised Fowler's own design of carburettor, very much like a Ruston Hornsby PT carburettor and similar in operation to the Lister D carburettor. It is not known how long this carburettor was used, however it seems to have been phased out around 1939 in favour of the mass produced Solex carburettors, I know of only one early Fowler with cast iron carburettor, which is unfortunately incomplete. The image below, apologies for quality, shows the early style carburettor that is rarely seen these days.

The PA and PD engines used the Solex 26 F.H.D. The larger Fowler engines used what appears to be the 26 F.V carburettor. Variations on carburettor model may have occurred during production, I would be pleased to hear of any such changes. The Solex F type carburettor was made in two models with variations, follow the links below for more detailled information (the pages contain large images).

Type F.H - Horizontal Offtake, with two variations:- F.H.D, float chamber on RHS and F.H.G, float chamber on LHS.

Type F.V - Vertical Offtake

Although different in appearence the F.V and F.H models function identically consisting of two main parts, the throttle chamber/carburettor body and the float chamber and main jet assembly. The float chamber is detachable from the throttle chamber by means of two bolts which can simply be removed. For starting purposes a strangle (choke) is fitted to the air intake. On the F.H models a 'guillotine' is placed immediately on the atmospheric side of the choke tube. In the case of the F.V model the strangler is a further butterfly spindle mounted in the mouth of the air intake. In all models of the F.V carburettor, except the 26mm, the strangler is a separate unit.

It is often said on the rallyfield that the Solex carburettor is a very crude unit and that Fowlers run much better using a Lister D carburettor modified to suit. I have had no experience of such a modification and am happy to report no problems with the Solex F.H unit. I would comment however that the Solex carburettor can often have a persistent fuel drip leak which is caused by a worn float needle valve. This can be cured by placing an extra fibre washed underneath the float valve to ensure it closes fully. The image below illustrates a well engineered Lister D carburettor conversion:- (click to enlarge)

A transcript with images of the full fitting & instruction book for the Solex FV & FH is available here coutesey of Peter Forbes Engine Information Pages.

• Exhaust Silencers:- A range of silencers were fitted to Fowler engines over the years.

  Image A shows the silencer fitted to an early prototype PA, note also the early carburettor once again. This is a pre-fishtail silencer, the fishtail being introduced later - thought to be more quieter and more refined than an open pipe to atmosphere.

  Image B shows the pre-WD Wolseley pepperpot style silencer which was used in batches during 1938/1939. Fowler bought in many Wolseley silencers to fit to their engines. I have not seen any other Fowler engines with this silencer.

  Image C shows the commonest silencer seen on the rallyfield. The fishtail design, developed from the original prototype from heavy gauge steel. This is actually a newly fabricated exhaust built to the same dimensions as the original.

A. B. C.

See Restoration Tips for information on making new silencers.

A. B. C.

Image A and B shows the early Lister D style tank.

Image C shows the more commonly used later style tank.

Unfortunately some tanks are just too far gone ! Can anyone help ?!

• Paintwork:- The correct paintwork for the Fowler range of engines is Light Brunsiwck Green to BS 381C-225. Engines were spray painted in a booth after assembly and testing. Some engines have been discovered with an unusual 'mottled' finish where a lighter green was sprayed over the top coat once dry. No one seems sure why this was done, however it seems that in the interests of economy and saving time this was quickly phased out.

  I use Blackfriars 'Green' QD90 Machinery and Metal paint for all my Fowler engines. The colour is very near the original and the paint is very durable for engine purposes as it it oil, petrol and heat resistant. It also has a very high gloss finish ideal for the rallyfield!