Alternative cooling fan/motor for V6?

[kaiser]

old motor in the lathe

[vitesse]

Thanks for the photo, saved for later reference, sadly only 1 hit on ebay but local scrapyards might be more rewarding.

Regards

[kaiser]

E36 I think.
But let's see if i can get it to work, and then if it fits.
The three fastening "ears" at the back are slightly out, for what I can see. I will let you know tomorrow, if I have the time.

[kaiser]

I have now tested the motor.
It is a two speed motor, with high speed obtained connecting only the fat blue and brown wires.
Reduced speed is achieved if the thin blue/black and fat blue wire is connected to the same pole and the fat brown to the other.

It now remains to be seen how well it fits in the holder!

[kaiser]

So the motor is in.
Straight fit? NO!!
1. The back plate with the ears of the motor is
a) wider, than the mounting hole!!
b) the mounting ears are off-set
That necessitates that the motor gets mounted from the back! of the cowling, and that new holes get drilled for the mounting screws.



2. The center boss for fitting the fan is also different: It has
a) a small dot, that needs to be removed to fit the Rover fan
b) modification to the fan center mounting bracket, where a bit needs to be taken off one of the three engagement fittings

Notice the small blob at the end of the screw driver?
Which fits in the groove seen at the bottom of the center of the BMW fan
This little blob needs to be taken off, as the Rover fan has not got that groove! If you force the fan on, it is likely to crack!

[kaiser]

The rover fan is seen here! Notice the lack of any groove!

the shape of the steel fitment screw is also different.
Here a paper copy of the Rover connector, place on the top of the BMW connector to show the difference.
Notice the piece of metal on the left, sticking out from under the paper?
That needs to be taken off, for the fan to fully engage on the connector.
Here it is marked with black on the left side of the connector:
Plastic to prevent filings from falling into the motor. Blow it out in any case when finished! Don't want any shorts.

And here it has been removed with an angle grinder and a dremel.
Notice the shorter ear, this time on the right!

After that the fan fitted, perfectly! And runs without touching anywhere.
Sorry about the slightly bigger pics, haven't got a clue why they suddenly are bigger.

tomorrow for fitting in the car and the electrical connections. The fan motor sits a bit closer to the radiator, because it is mounted about 4mm closer, fitting unto the cowling from the other side, and not sunk in from the front.
It is important that you get the centering of the motor correct when drilling the new holes, otherwise the fan will touch. If you stuff it up, you can use the BMW fan, which is smaller, and will clear, but you will lose some flow, because the fan is smaller and does not fit snugly to the outer shroud, resulting in some losses.

[vitesse]

Thank you for the Sherlock work and the photos, good even oversized photos are better than none. Shame the rear “ears” didn’t work, did you consider swopping the Rover end plate for the BMW one?

Regards

[SCP440]

I wonder if this is an option, even the mounting for the fan looks similar
https://www.ebay.co.uk/itm/Radiator-...1/173274720106

[kaiser]

So the motor is now installed and working fine.
However there were another few pitfalls along the way.

This particular fan motor is about 15mm longer than the standard Rover unit. All of the length sits toward the back of the mounting lugs.
Fitting the motor from behind the shroud, makes the fan fit perfectly in front, with a couple of millimeters clearance for the fan to run in the shroud.
However, it makes the fan motor sit too far back, and it will touch the condenser.
So there is no other option than to fit it from the front, but that necessitates reemoval of some of the metal on the "lid" of the motor. See the following photos.

The motor as fitted first, from behind the shroud.


The backplate taken off the motor for surgery. Notice this is a two speed motor and although the plate looks familiar to the original rover motor, it is different.

This is the backplate after surgery. I have taken off about 3mm of sheetmetal the whole way around, and cut the lugs so they would fit into the recesses in the shroud from the front. I used washers to bolt the lugs to the shroud with stainless screws and nylocks.
Notice the fan now fits from the front, which have brought it forward by about 8 mm, I used a flat 3mm washer under each lug to move the whole motor about 10mm forward. I could have left out the 3mm washers!

The motor now is moved about 10mm forward, and is well clear of the condenser.

The motor as finally fitted now dropped into the shroud, like the original motor.



the extra length can be seen here, as the fan has moved forward.

[kaiser]

Fimally the fan in the car and running!








for anyone that want to do this, the following information:
Wiring:
In the control box, there are three relays.
They control the 3 speeds of the original motor. the heavey wires to the motor work as follows:
Black is earth.
Red plus black low speed triggered at 100 degrees.
Red and Grey plus black second speed at 105? degrees/
Red and Grey plus black and purple third speed at about 112? degrees.

The small control wires in the relay box are:
Yellow provides positive to the coils on all three relays.
Blue energises the biggest relay for the low speed.
Blue and yellow energises the medium speed
The last blue (with a trace colour that I forgot to note!) triggers the high speed.

Trying out the fan motor that I got from the BMW, the first thing to note is that they use different colours for the wires, The BROWN is negative!! and the blue positive and the smaller blue and black triggers the lower speed together with the heavier BLUE. If you get this wrong, the fan turns the wrong way.

Triggering the low speed, by connecting BLUE and BLUE/BLACK together plus BROWN on negative, makes all wires hot. The lower speed is thus obtained by feeding current in the motor to oppose!! the turning.
I think that is complete madness, and decided to just use the faster speed, thus just using the RED and BLACK wires from the original loom to the motor, and disregard the rest of the speeds.

The car now runs with one speed. It seems to me like a speed lower than the emergency third speed on the Rover motor, but most likely close to the second speed, maybe slightly higher than that of the original motor.
I have taken it for a drive now, with outside temperatures of about 30, and the car runs up to 100, the fan kicks in and it goes to about 102, before dropping to 96 in a few seconds and switching off. Leaving the AC on it keeps the engine at between 85 and 87. the car has one of my aluminium thermostat housings with an 80 degree thermostat.

All in all doable, but with a bit of surgery required!
Oh, the fan is brand new (off a German car from a friend of mine that imports BMWs from Germany) It is stamped 97, but the brushes are all same length and close to the maximum that could have been fitted.
The motor should last about 10 years, I guess!
Problem solved.