Sorting through the wiring harness on Fiona - she's a bit of a "Franken-Mini", originally a '91 SPI converted back to carbs (so there's some stray, extra wiring hanging off the harness here and there, left-overs from the ECU and assorted electrics). I recently replaced the engine when my original one was lost in a fire, and I'm trying to trace where everything re-connects. Having trouble finding a connection for these leads - they're right up front in the main wiring bundle, a pair of leads, one green w/ white stripe and the second black. the connectors are beefy - definitely meant to carry some current: My only clue is that in some wiring diagrams, there's a sub-circuit for the auxiliary electric cooling fan (which I do have installed and that did work on my old engine), and that relay uses a white and green wire to energize the system. I'm wondering if there was some sort of electrical switch that attached to the engine and/or the thermostat housing (or nearabouts) that these leads clipped to, which triggered the fan relay when the water temp rose high enough? This would, I assume, be a DIFFERENT sensor than the one that's used to drive the water temp sensor (that's a single-connection brass sensor that threads into a hole just below the thermostat and connects to a green w/ blue stripe wire, which I also have). Does anyone have a late(er) series Mini that has an electric auxillary cooling fan, and of so can you look and see what leads trigger the fan to come on when the temp rises? Thanks!
Argh! Found it - there's this connector on my old radiator, that obviously is the sensor switch for the temp-controlled electric fan: As my new radiator lacks this sensor, I guess I'll have to rig up a cabin switch to drive the fan via relay, instead. thanks guys - sorry for the un-needed thread.
Ok it's obvious! The green and yellow one goes to the thingmabob and the other one goes to the thingamgig.
If only the pictures could be a little bigger............ You can buy a sensor that attaches to the radiator core so you can retain the auto function - it simply attaches to the core with some plastic thru ties.....plus you can wire a switch in as an auxiliary too. This one is adjustable for on/off temps.... http://www.summitracing.com/parts/der-16759/overview/
That's fine for a temp sensor, but would it be appropriate for a fan switch? I mean, is that the right location for accurate control of the fan? Although that does give me an idea about my original temp gauge - since I added a mechanical gauge, I had to disconnect the electrical version, that would let me hook it back up again.....and if I put it in the lower radiator hose instead of the upper, it would give me a good idea of how much cooling is taking place in the radiator......
A fan switch in intimate contact with the coolant liquid, monitoring the temperature, will always be quicker to react and more accurate than one taking the temperature of the air passing over the fins in a radiator.
Thanks very much for the switch link, but I think I prefer to just manually control it - I've seen some others who have done so and always planned to do it at some point... now I no longer have any excuse. I plan to delete the relay currently in the automated circuit and replace it with a manually-controlled one with a cabin switch. The more I look at my current wiring situation (read as: "rat's nest") the more I just want to cut open the manly, electrical tape-wrapped bundles and just start cleaning house... it's so nice in there now, and the effect is really ruined by the effed-up old wiring.
My aux fan is switched manually. I've got a light next to the switch to remind me it's on, not that it was necessary, but it serves a purpose. Anyway, since our climate out here is usually warm, my fan is almost always switched on, therefore I've no need for a sensor.
I prefer letting the sensor keep on top of things, in case I don't notice the temp climbing due to traffic or something - the supercool 3 core rad both Matt and I will be using has a threaded hole for a sensor I believe. If not you can also use the ones that attach to the upper hose (which seems to me a better location than the bottom of the rad - although that's where the factory Mini sensor was/is too. This is the one my car has......but I'd switch over to a threaded sensor in the rad if that's a better, more accurate way to do it.
You're probably better off having the temp sensor in the water line or the radiator as opposed to a thru the radiator sensor. It'd be much more accurate there. We have a threaded tap in the lower tank of the radiator in the race car that activates the water temp gauge. We do not run a belt driven or aux fan. Our radiator faces forward and air is simply force fed through the coils at speed. On my street car, I run a 3 core with the belt driven tropical fan for more air movement, as well as the aux fan affixed to the inner wing panel.
The six blade metal. It's supposed to move more air than the 11 blade plastic, from what I've read. Not sure on the percentage though.
My guess is the plastic fan even with more blades flexes as RPMs rise. The metal fan is not going to flex, that could mean the metal fan is more efficient as the RPM rises. Just an old farts SWAG.
Could the metal fan be more parasitic to horsepower at higher rpm's because it doesn't flatten out ? I understand the goal here is for regulated temperature control but with a more efficient radiator transferring heat could the metal fan be overkill or are the radiators so small that they need lots of help ??
I'm sure there is more parasitic drag from a metal fan that doesn't flatten out. I don't drive a classic, but if I did I'd give up a few HP to keep my engine happy.
I agree about a happy engine. I remember aluminum bladed fans that would pull a goodly amount of air at low speed but then at higher speeds they would flatten out. They might have been more of a muscle car / drag racing thing.
The bottom line here, in my opinion, is this... These early cars (pre October 1996) have radiators mounted on the left side of the car. By design, these do not get a natural air flow over the face of the radiator. As our US climate is typically much warmer than that of the UK (where the original design was born) a maximized air movement set up is most desirable. The Tropical fan pushes more air through the radiator, which is assisted by the aux electric fan, standard on all later 1275 models. Hence my reasoning for the two applications I've chosen for my California Mini. I'm not at all considering a +\- horsepower factor in the least. While a large portion of these cars are modified and are faster and more powerful for their age and design, they won't be for long without effective cooling. Back to temp sensing... As the flow of water is into the bottom and up through the radiator to the top tank and on into the head, place your automatic fan sensor in the bottom tank for best temp sensing accuracy. If you've got a side mounted radiator, fit it with a sensor that will turn the fan on at 98 degrees c and off at 93 degrees c. If it's a front mount, the sensor should switch the fan on at 105 degrees c and off at 98 degrees c, respectively. Hope this info helps...
Nope it's the other way round....heat rises, cold falls..... The hot water comes into the top of the radiator and goes out the bottom, that's why the lower hose goes into the water pump - that's the suction side. The only car I know of (stock-factory) that does it the other way are newer Corvettes....makes sense to me that you send the coolest water into the head, but that's not how it's done (except the Vettes) It harkens back to the early days of the Model T which had no water pump, but cooled by thermosiphon - as the hot water rose thru the block it created a suction at the bottom..... cool water was drawn out of the radiator at the bottom, and the natural convection caused it to circulate.