At the launch of the Seal engine in 1947 Westbury noted that "It is my intention to produce designs for engines of both 15cc and 30cc, and equipped with either side or overhead valves". In 1950, with input from Westbury, the Seal Major was designed and released by David Braid.

This engine has proven to be equally as popular as the Seal. The essential differences for the Major are based solely in its capacity. Bore x stroke = Ø7/8" x 13/16" giving 32cc or 1.95cu.in. With this simple change however, every single casting becomes larger than the Seal. Larger diameter pistons and liners dictate a longer, wider block, head and sump. Additional length in these components dictates a longer manifold…and so on.

Underneath it all however, this is the same elegant 4-cylinder side-valve engine as the Seal. So, why would you choose the Seal Major? A couple of reasons:

· As the American's say "nothing beats cubes" and the Major has more umph. It performs well in 6ft launches and will even power a 5 inch gauge locomotive.
· For the constructor, the extra size of the components (generally 30 - 40% larger) is often welcome.

In August 1959, author and engineer Neivil Shute wrote to a close friend:

"At the moment, however, the Seal Major engine is engaging my attention, and that will keep me busy for a quite a time although now that the book is finished I shall be taking a month or two of holiday and shall get on with it a bit quicker. So far, cylinder liners, pistons and gudgeon pins, and valve guides are finished, together with the timing spur wheels, and I am now starting work upon the crankshaft to be followed by the camshaft. I think the best plan on a job like this is to get all the bits and pieces made and then to tackle the final erection in one go when everything is to hand; otherwise one might tend to get in a bit of a muddle and one might find that parts already faced up and assembled might require some small alteration."

3 A2-size drawings compiled by D Braid. No dedicated build notes are available for the Seal Major - this item is supplied with Westbury's copious notes (58 pages) on the smaller Seal engine.

The Seal notes are perfect to demonstrate the processes and procedures; clearly all dimensions given in the text should be ignored!!

Whilst not quite exhaustive, the kit includes material for the major items required to complete the engine as originally designed with its direct mounted distributor. Constructors will need to find (or make) various items including hex fasteners.

The bill of materials for the Seal Major kit includes:

· (11) Aluminium sand castings
· (8) Iron Piston Rings
· (8) Valve springs
· (3) Timing gear train
· (23) Sawn lengths of bar material (free cutting, high tensile, and silver steel, bronze, cast iron, aluminium, Dural, brass and Tuffnol)
· BSF hex nuts

Electrical components (points, coil, spark plugs...) can be found separately in the IC Engine Accessory section and plans and construction notes can be ordered above.

If you want to minimise shipping costs or if you are particularly well stocked with supporting materials, you may prefer to order just the essentials. This item buys the 11 castings available for the Seal Major:

Cylinder Block, Head & Cover, Sump, Bearing Housing, Timing End Plate, Timing Cover, Manifold Body & Cover, Valve Cover, Carburettor Body