Out of the past — a mystery

A reader has asked me to identify two photographs: one is a Coupe de l'Auto Calthorpe with its imposing radiator. The bonnet straps and bolster fuel tank imply a racing car, rebodied later on with mudguards, headlamps and passenger's step.

It appears that this is the car driven in the 1908 'Four-Inch' TT race in the IoM by Leslie Porter, who finished fourth. With help from the Midland AC's archives, it seems to have been this Calthorpe with which Mr Clive Bluitt competed at a 1909 Shelsley Walsh closed meeting.

As usual, however, there's a problem! The TT regulations called for a cylinder bore not exceeding 4in, but at Shelsley Mr Bluitt's car was quoted as having a 93mm bore, whereas a 4in bore equates to 101.6mm. However, in the 1908 TT the Darracq, Westinghouse and Rover cars had bores under 4in. Or was a production 16hp engine substituted when the car was converted for road use?

The identity of the car in the other photograph should be obvious from the unusual arrangement of its front spring shackles. These consist not of the normal plates but of thin, almost full circle hooks, connecting the half. ellipticfront-springs to the slender dumb-irons. If these hooks look rather too slender for their task, similar frail-looking links were used on the big Mercedes and other cars of those times, and they also sufficed for Count Zborowski's Chitty-Bang-Bangs on the rough Brooklands.

Other identification aspects are the substantial radiator feet, the mean dashboard and those protruding hub caps. It is thought that the car is being driven by the aforesaid Mr Bluitt, a founder member of the MAC, and that the passengers include Mr Arthur Cox, an original MAC member, and Mrs Baker. The car, Birmingham-registered, is said to have belonged to Mrs Baker's grandfather. Mr Cox competed with Rileys in 1909-13.

After much research, I'm defeated.

Any ideas?