mr rusty wrote:My theory, for what it's worth, is based on the A series: in that in that case 1275cc was about as far as the design could be pushed from the original 803cc and stay reliable without major retooling and redesign. Tax breaks based on capacity (as opposed to stroke) didn't really come into it for the UK until the 80's when 1400 became the new 1300, and bought with it a whole new range of engines from the big manufacturers.
As with all things, if you can cheaply stretch say 1 litre to 1300, you can charge more for it, and at a bigger margin too.....
This isn't far out I'd say. Most smaller engines could stretch from 850 to 1300. The VW 1200 was stroked out to 1500 (The Beetle also got this engine for the dearer models), as was the Triumph SC engine. It was due to this that the MG Midget got the engine, as the 1275 A Series could no longer take the U.S emmision regulations and give sufficient power (People have taken A Series out to over 1500 cc but it was not considered viable by BL; I wonder whether this was because the Triumph engine had already been done
).
Taxation had been based on cylinder bore, which was one reason why older engines were long stroke. When owning a car was a luxury, it followed that some people might be able to stretch things a bit and get a small car but not a bigger one (In the late 1940s, after a three year wait, my grandfather took delivery of an A 40 Devon, which had a 1200cc engine, from which
grew the B Series; at the time, there was only one other such car in the borough). Go back to the 1950s and a 1500 car was quite something; if you had an MG Magnette most people (Who had cars) were driving Standard 8s, Morris Minors, Austin A30/35 or Ford side valve cars (Not to mention pre war cars). By the 1960s, aspirations were rising and with it engine sizes.
Rules exist for the obedience of fools and the guidance of wise men.
MG Midget 1500, MGB GT V8, Morris Minor Traveller 1275, MG Midget 1275 & too many bicycles.
