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MG MGB Technical - Replacement electric fans

My Kenlowe electric fan motor has packed up, probably after getting soaked in floods last week.

The control unit and stat are OK so I'm going to try to source a fan from a breaker's this time. Does anyone know which cars have a fan that might fit (UK breaker) and how do a tell a "push" fan from a "pull" fan when it's off the car?

Thanks

Steve Postins

Steve,

the one from the Chrysler-Sunbeam 3 door estate from the early 1980's looks like the ones used on late MGB's and the V8. If it is just the Kenlow vent, there are many alternatives that will fit in front of the radiator.
Depending upon the year of your car, also some air condition vents from modern cars shold be O.K.

I fitted one from a Ford Galaxy in front of the radiator of my 1975 RB but had to fabricate a frame for it. I bought the set of two of this vents at a breaker to at 10 Euros as the mountig frame was broken.

On an 1973 BGT i once used a Bosch vent from a 323 BMW in front of the radiator as there was limited space for a larger one.

If you are going for an other vent than the Kenlow, don't forget to also add a relais and an additional fuse, as the Kenlow switch is not capable to switch the current of some of the modern vents.

Hope this helps

Ralph

Ralph
Ralph

Steve,

if you look at the fan blade edge on, it is shaped like a little aeroplane wing, with a curved side, and a flat side.
Air is sucked from the curved side, and blown away from the flat side. (If the motor runs the correct way)

Usually, you can turn the fan blades round AND reverse the leads to the motor to change a "puller" into a "pusher".
Martin Layton

Thanks for that. I've put a 3-blade mechanical fan on for the time being and can't get over how much noisier the engine sounds. I was debating the value, but the electric fan wins out thanks to that and the cost in petrol and bhp; it only ever ran after getting stuck a while in traffic, even in warm weather.
Steve Postins

Steve
I found that Pacet electric fans are much better than Kenlow,Very efficient and quiet I bought mine from Stafford Vehicle Components www.s-v-c.co.uk
Ed Campbell

I looked into the costs and ended up using SPAL fans.

1 pushing and 1 pulling with a small overlap.

The puller (more efficient) was run off the thermostat and the pusher was run manually when needed.

I am very happy with the result.

Dave
D M Tetlow

Hi Dave,

"The puller (more efficient)” how’s that then?

From a thermodynamics point of view the density of the air will be greater if the fan is in front of the radiator, as the air will be cooler and therefore more therefore dense, giving a greater mass flow and therefore cooling efficiency.

The fan is a constant flow device, so you want the greatest density air for it to work on.

Mounted behind the radiator, the fan electric motor may draw less current, granted, as the air will be hotter, less dense, so less load on the fan motor, but defiantly not more efficient.

Two fans is series, would only be used if you could not overcome the system resistance, not likely in an MG, although, staggered, would increase the effective area, but the one behind the radiator will produce less cooling effect.

The advice that the "The puller (more efficient)” is not correct, from a cooling point of view, but would draw less current.

sorry.
MG Mike

"therefore more therefore dense, giving a greater mass flow and therefore cooling efficiency"

This sounds like the old airplane argument that puller props are more effective than pusher props, or vice-versa, when in fact both are the same.

Puller fans *are* more effective in practice. Pusher fans tend to fling a lot of volume off the tips of the blades which never goes through the radiator. By contrast a close-coupled electric fan i.e. one attached to the radiator will pull the vast majority of the air it moves through the radiator, even when not shrouded, whereas a pusher has to be shrouded for greatest effect.

A given fan used both sides of the radiator may well take less current on the puller side, but that is because the air is already being pushed through it by the pusher fan. The reverse is also true, having a puller fan as well as a pusher makes life easier for the pusher as well, which will also take less current than if there wasn't a puller.

But this is getting into the realms of how many fairies can dance on the head of a pin, especially as an MGB shouldn't need additional cooling anyway. These cars run in desert states with no problems - if the rest of the system is up to scratch.
Paul Hunt

This thread was discussed between 10/06/2008 and 20/06/2008

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