Fan - Tastic!!!

 Hello again Cobra blog readers. Firstly thanks for you for your patience for what seems like a huge gap since the last update, to quote my mate Ian Cogden "life has got in the way" i have took on another day job which sees me working even  further hours and along with my little mates 3rd birthday, spare time and energy has been very very thin on the ground.
  So to kick of this update I'll summarise my twin cooling fans install. I have always loved the look of the front twin fans, and followers of my progress will recall i have a thermostat controlled puller fan behind the radiator. So this is the "belts and braces" part of my cooling system. I'm putting two classic style fans in the front nose that will be switch controlled, so if I'm stuck in traffic or start running hot, then i have some additional cooling available at the flick of a switch..... i so i hope!!

So firstly i needed the motors. Many options are available (mostly cheep Chinese motors) but the big beefy ones off an MGB were what i opted for. These are actually fairly hard to get hold off new, but i dropped on with eBay and managed to pick up two for a total of £60. Most MG suppliers list the motors in their parts, but the availability was poor through all the suppliers i contacted.

I had picked up a couple of 30 year old fan motors from a MG breakers yard but they were past their best and the bearings were shot (however the mounting brackets came in use) The motors i got had an 8mm spindle shaft for attaching the hub/fan, i believe the original MG motors also have a 8mm hub, with grub screw thread. They are 12v DC with just over 3000 rpm. 

Next on the list was the fans themselves. These are just of an industrial fridge/freezer. I picked up a couple of 250mm fans for less than £10 including postage from an fridge repair website. The fans i got were just pressed alloy with no hubs or fixings attached. This did become a little obstacle to overcome, as i found getting a suitable hub a little bit of a challenge.And after a couple of experiments with odds and sods i had lying around it ended in failure. I then, after google searching everything i could think of, came across a robotics website that listed a robotic wheel hub for a 8mm motor shaft and at £3 each they were hardly expensive. I had just been speaking to Lee that day (the original inspiration for these fans, off the Cobra forum) who informed me that you could get the fans with the hubs already fitted, but with these in the post i thought i would give them a bash. When they arrived i was very pleased with the quality of them and the engineering in them for the price. They have a perfect 8mm centre, secured with a nice allen bolt, and 6 equidistant holes for the fitting of a wheel.... or fan in my case. These were just simply drilled through into the fan and held in place with some little M4 nuts and bolts (all with a little locktight for extra security)

 As you can see in the picture, it all went together fairly nicely and more importantly well balanced. you cant have these spinning round at over 3000rpm an inch away from your radiator without them being balanced, they would just shake themselves apart otherwise. Once the two motors and fans were fitted the obligatory "bench test" was carried out and the torque from the motors was very very impressive, along with the amount of air they were pushing, more than sufficient for additional cooling. In fact i believe Lee was using his as his primary cooling system controlled through a thermostat but again that would be more than sufficient.

So with the motors and fans ticked off the list, next up was the fixing bracket. This is simply just a length of box section, with angle brackets either end, and with the original MG style motor clamps bolted on. I say "simply" but all this takes time of measuring and cutting, measuring again, trail fit and then spacing of the brackets with the motors and fans fitted. The whole bracket is then fitted into the nose at the desired angle and height and secured with some bolts through the inner wing which is 5mm thick fibreglass with the stainless steel cladding, so certainly strong enough.

So now a trial fit of everything, and when i stood back to have a look i was very very pleased with how they looked. And with it all in place another quick test run with a battery back to see how they worked... again very very pleased. So stripped it all back out again, so i could give the bracket a good coat of chassis black Por15 (which is the same tin i purchased back when i did the Jag parts refurb.....cripes that was a long time ago)

Once everything was back together and installed on the car, it was time to route the wires and fit the dash switch. If you have followed my blog you may recall that i fitted an additional fuse box specifically for bits like this which were planned at some point during the build, and I'm glad i did. So not too challenging to feed some 27amp wire along from the motors to a 24amp toggle switch hidden behind the wiper control stalk (within the IVA dash exempt area) then with a 20amp fuse it was ready to test. Fitting of all these wires and the routing all takes its time and in fact i spent more time doing bits like that then on the initial install of the bracket with motors. But if a jobs worth doing, its worth doing well.




So i suppose you would like to see how they work??? well watch this video and you will see. The frame rate of the video gives the appearance the fans spin in opposite directions, but in reality they spin allot faster than it looks and both anti-clockwise.