Daimler V-8 engines were designed for the Daimler Company by Edward Turner and produced from 1959 to 1969. Initially used in the SP250 sports car and the Majestic Major saloon, the engine was mostly used in the Daimler 2.5 V8 (later named V8-250) saloon made with Jaguar Mark 2 unit bodies from 1962 to 1969. Approximately 20,000 of the 2.5-litre version of the engine were made for use in the SP250 and the 250 saloon, while approximately 2,000 of the 4.5-litre version were made for use in the Majestic Major saloon and its limousine variant which remained in production until 1968.
Design and development
Shortly after being appointed Managing Director (Chief Executive) of BSA's Automotive Division in 1956, Edward Turner was asked to design a saloon car powered by a V8 engine. Turner and his design engineer Jack Wickes began considering the initial concept of their new engine by examining the manual and spare parts list of a Cadillac V8 engine. Using a pushrod overhead valve system kept down design, development and production costs and allowed Turner to base the design of the cylinder head on those he developed for Triumph motorcycles including the use of hemispherical combustion chambers. Adapting the Triumph head design for use in a saloon car engine required much work in reducing friction and improving timing. Much of the development of the prototype engine was carried out by Dr. J. N. H. Tait. Tait had been involved with Donald Healey in the early post war years, working successfully on modified Riley 2½-litre Big Four engines, the final incarnation of which was used in 1953 Zethrin Rennsport prototype, delivering close to 200 bhp with surprising tractability.
The two sizes of the Daimler derivative engines share similar but not identical external dimensions and design, the 4.5 litre being longer, deeper and wider. Although it is just possible to substitute one for the other, it requires a good deal of alteration of mountings, exhaust piping, etc.
Limited investment in tooling for the 2.5-litre engine led to limited production capacity, with a maximum weekly output of 140 engines, and the 4.5 litre was only ever made in small quantities. This prescribed maximum output was never achieved during the production of the engine.
Specifications
The 90 degree V8 engine has part-hemispherical combustion chambers with two overhead valves per cylinder operated by push-rods from a single chain-driven camshaft positioned centrally high up in the vee. Aluminium alloy pistons with steel connecting rods run in a cast chrome-iron block with sand-cast high-tensile light alloy heads and crankcase housing a short stiff dynamically balanced crankshaft carried on five bearings. The nose of the crankshaft carries a torsional vibration damper, a four or six-bladed fan, and the pulley for the triangulated thin belt drive for the dynamo and water pump. The dynamo is located between the cylinder blocks on the smaller 2.5. At the rear the drive is taken from the back of the camshaft for the distributor positioned high above the unit behind the two semi-downdraught SU carburettors. There is a separate exhaust system for each bank of cylinders. Light alloy is used for the valve covers, tappet blocks, sump and inlet manifolds. Cooling is by pump and fan with a thermostatic by-pass control.
Applications
The engine first publicly appeared in the Daimler Dart but, after Chrysler objected to use of that name, it was called the Daimler SP250, a fibreglass bodied sports car aimed at the American market.
In December 1961 Daimler announced a marine version of their 2.5-litre V8.
The 2.5-litre engine, only in length and developing @ 5,800 rpm, gave better performance than Jaguar's own 2.4-litre DOHC in-line six, and after the 1960 merger the opportunity was taken to create an up-market Daimler V8 version of the Jaguar Mark 2. Between the years 1962 and 1969 17,620 Daimler/Jaguar V8s were built. Initially called the Daimler 2.5 V8, it was later called the Daimler V8-250.