Water pump/fan

[Tim Neville]

I know that a number of people have electric fans with considerable success. Iam not inclined to go down that route in the cause of maintaining originality,
if I want mod cons I drive a modern car! But, from a technical inquisitiveness point of view I've 'mulled over' a couple of ideas.

The coolant circuit alteration returning water from the head to the heater tap, we all know about and I think is probably essential. But I have also wondered about increasing the pressure and rate at which water is circulated by decreasing the pulley diameter. This will also of course increase fan speed making it important to have a good well balanced fan. For fast heat up we don't want a fan running but we do want rapid circulation. Once up to temp and the 'stat is open we want a fan. The answer and a possible compromise between absolute adherence to originality and effective heating/cooling is a sensor operated electro-clutch on the fan shaft. It should be a relatively simply engineering mod. Has anyone already done this and has anyone any comment?