I remember someone in the series one club had one on a 2.0 petrol 86" that he used dayly all year round. Havn't seen him for afew years though. I don't think he used the kenlowe often, only on winter mornings as it gave the heater a chance to do something. (he loved it for that resion but it just didn't need it in the summer).
When you say you want to speed up warmup what does it do? Whats it run at when warm and how long does it take to get there? Both my series 1's get up to temp fairly quickly all year round. Ones an original 2.0 petrol the others a 2.25 diesel with early style rad. When I say get up to temp however I mean struggle to get over 60°C - After a 5 hour thrash on a hot day with long hill climbs the diesel still doesn't get hotter than 70°C. Its in the workshop at the moment and I've just bothered to findout its got a 74 thermostat in it. Going to fit a 82°C stat instead to see if that helps; as it does about 7k miles a year I'd like it to be running slightly hotter. The petrol isn't used much so I don't worry about it if its not overheating.
If its running cooler than 60 or taking ages to warm up maybe the thermostat is missing or jammed open, 60-70 is probubly normal. I'd think about pulling the top hose off the rad and have a look, you won't loose much water. They only cost a few quid anyway so its not like theres much to loose.
Electric fans can help them run hotter at slower speeds, used to have one on the petrol untill the fan was filled with mud and died. Above 40mph it was still overcooled (fan off, water nearly 70 which was a slight improvement) but at slow speeds the fan would keep it at 80 (ie what I set it too) and so worked quite well. Warmup was slightly better with the electric fan as it wasn't spinning, it wasn't that drematic howver as at low temp the thermostat kept the rad out of the loop anyway. It's back on a mecanical fan at the moment as after the electric was removed for repair I thought the original system seemed more in carictor with the series 1 not having a fan cutting in and out all day like a modern french car, or you worrying if it would cut in. The petrol motor doesn't get used massively so its not going to make a dramatic difference if its not spot on thermal efficency. Engine ware on coldstarts probubly more efected by good or bad oil.
In short if the [cheep] thermostat is okay I wouldn't worry, its survived the last half century as it is so it'll be fine. You'll doubtless save a fair emount of money not getting a Kenlowe and the series 1 WILL find another way to consume that saveing.
