The early development of the three cylinder Triumph/BSA engines showed the need for cooling of the oil. This was because the oil flow rate in the three cylinder engine is between six and seven times that in the Triumph twin engine and a higher proportion of the waste heat goes into the oil. Also the higher power output of the three cylinder engine increased the amount of waste heat to be dealt with.
Various oil coolers were tried and the problem was then given to the company for whom I worked at the lime (Coventry Radiator and Presswork Co. Ltd. - later known as CovRad Heat Transfer). I worked on the specification of the cooler and also on test programs using a Trident on loan from Triumph at the MIRA (Motor Industries Research Association) test tracks and in their full size wind tunnel. I worked primarily with the Triumph Meriden Development Shop - in particular Norman Hyde, the development engineer, and Alan Barrett, the development shop foreman.
At the time fitting an oil cooler to a motorcycle was a major step in terms of extra components, complexity and cost so the oil cooler was specified but no oil temperature control system was specified.