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MG MGB Technical - Cooling Fans

I will be putting the engine and cooling system back together this spring and am taking the rad in to be refurbished. The rad shop can install a fitting for an electric fan temp sensor/switch. What sensor/switch should I use?

In converting to electric fan is it better to use a fan that pushes (mounted in front of the rad) or one that pulls (mounted behind the rad)?
N. A. Peacey

N.A.,

I have had good luck with my original Lucas switch in my '77, its still working after all these years. However, it may be more expensive than something you could find at a local auto parts store and may become difficult to find in the future.

I don't think there is much difference in the performance of a pusher versus a puller fan. My car came with pusher fans and I have a lot of room in front of the radiator, you didn't mention the year of your car but I assume it may not be of the RB variety because you say you are converting. If you have an oil cooler up front you may have to rearrange some things. Setting-up as a pusher provides a good bit of working room at the front of the engine.

Doug
D. Cook

I don't have a recommendation for a switch. I would NOT use the one for the late (77-80) B's as they are prone to pop out. The Moss kit fans normally come with a switch that mounts to the fins, so rad modification is unnecessary. Supposedly a 10" will work, but a 12" is better, and there is plebty of room. A puller fan is significantly more efficient than a pusher, especially if shrouded.


Paul K

If a 12" shrouded puller is better than a comparable pusher, would a matched pair of shrouded 8" pullers be better? I have 2 that will fit side by side on the rad frame behind the rad.
N. A. Peacey

A puller fan is best as a pusher blocks the core. I HIGHLY recommend a 13" Spal fan. Not cheap and draws quite a bit of juice but that sucker really does pull a lot of air compared to almost anything out there and I've had quite a few. Draws 15 amps and you need to use a relay but that baby will keep your baby from overheating. $150 through racers warehouse.
Mike MaGee

NA: the trick is to go to a junkyard and pick up a radiator out of an old VW or Fiat or Porsche, get a bashed one ,as all you really need is the sensor adaptor.Have the adaptor installed in the bottom of your radiator, start with the sensor that comes with the junkyard radiator, if you feel the need to go cooler or hotter, Porsche part suppiers have what you need.
One of the best thimgs about these sensors is they handle high amp, wire it straight or with a relay it will work like a champ.
RIC
R E L Lloyd

I mentioned an MGOC sensor in another recent thread. I recommend this device - it is an aluminium tube with a built in electric switch/sensor. Coolant flows through the tube (located in the upper radiator hose) and it is fully adjustible.

I've had the fin sensor as well as the Kenlowe bulb. The MGOC device is an elegant and efficient design.

The club's description is as follows:

Thermo Fan Switch
This adjustable cooling fan thermo switch provides an accurate and neat method of setting the temperature point at which the electric cooling fan cuts in. Suitable for use on cars with either standard equipment fans or aftermarket fan kits fitted. (ie Kenlowe). Available in two sizes, 28mm for most midgets and MGBs, and 38mm for MGC and V8. Chrome bumpered MGB needs additional fitting kit, see below.

Price: £39.95 Including VAT at 17.5%


http://www.mgocaccessories.co.uk/acatalog/MGOC_Accessories__Fan_Switch_183.html


rn
RN Lipow

N.A.-
A pair of 8' fans would have an area of 201 square inches while a single 12" fan would have an area of 113 square inches. A puller fan is 10% more efficient than a pusher fan of the same specification.
Steve S.

My thanks to everyone. This has been very helpful. As I already have the 2-8 inch pullers I will mount them and mount a temp switch in the bottom of the rad.
N. A. Peacey

N.A.,
Is there a specific reason that you'll mount the switch in the bottom of the radiator? Seems to me that the real engine temperature would be better read in the top tank, before the cooling effects of the radiator. Is my thinking wrong on this? Joe
Joe Ullman

Steve,

I like your idea of two 8ft fans! Sounds like a small aeroplane! I think there's a small arithmetic problem. Two 8in fans give 100 sq in; one 12in fan gives 113 sq in.

You might find an even bigger fan readily available in the US; we can get 16in fans here in the UK.

Regards

Peter
P L Hills

Joe U: if you use the top as a mount spot the fans will run all the time or at least more then you might want.If the coolant is cool at the bottom the fans are not needed and in fact may cool to much. RIC
R E L Lloyd

The single larger fan should be even more efficient than the swept area would indicate. Fans don't pull much air through the hub portion and the dual fans have have twice the hub area.
George B.

This thread was discussed between 26/01/2004 and 28/01/2004

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.