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Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 12:28
by bmouthboyo
Unfortunately after shot blasting and painting a replacement metal radiator shroud for my rusty old one, which I chucked away... My fan doesn't fit
Ideally I'd like to fit a late fan to my prepped shroud but seems wiring is different with only 2 connections but my early has 3:
[IMGhttps://i.imgur.com/75p9exQ.jpg][/IMG]
Anyone know if I can simply splice, and if so how to go about having 3 wires on my connection block?
Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 13:13
by Mocki
two speed fan.....
brown is neg(-12vdc) red is first speed, red/black is second speed iirc
Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 13:20
by bmouthboyo
So the later fans with only 2 connections don't have 2 speeds?
Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 15:32
by bigherb
Their are three different types of fan.
Single speed two wire
Two speed with three brushes, three wire
Two speed with external resistor three wire but only two to the motor.
Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 16:36
by syncroandy
The below applies to 85-on, before that YMMV:

Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 17:12
by bmouthboyo
Mine is 83, what does YMMV mean?
Electrics are a bit of a dark art to me unfortunately so this is a bit over my head.
In a nutshell I cannot simply connect a late fan sold by the likes of brickwerks to my existing early 2 speed wiring?
Re: Swap early Radiator fan for late, wiring question.
Posted: 04 Aug 2017, 18:39
by syncroandy
'Your Milage May Vary'. If you're buying a fan from Brickwerks they may be able to advise on compatibility. I have no data to hand on pre-85, so I'm reluctant to comment further.
Swap early Radiator fan for late, wiring question.
Posted: 05 Aug 2017, 07:46
by bmouthboyo
syncroandy wrote:'Your Milage May Vary'. If you're buying a fan from Brickwerks they may be able to advise on compatibility. I have no data to hand on pre-85, so I'm reluctant to comment further.
No problem thanks for your advice. I ended up salvaging my old rusty radistor shroud to fit my original early fan.
I will keep the recommended cowling and look into fitting a late fan at some point. Are they more powerful than my current early 2 speed? Displace more air?
I really need to learn some basic electrics but the diagrams confuse me. Any good guides around ad to the basics of say Haynes wiring diagrams? Like why I seem to see 87 and 30 so often, do they have a significance? And what does the black box with 5 in mean?
Re: Swap early Radiator fan for late, wiring question.
Posted: 05 Aug 2017, 11:54
by CovKid
I suppose what you could do is hook two-wire fan to low speed wire. It would work fine but always be noisy when it starts up as it would be running flat out. I would imagine it would be on/off all the time as it would cool more rapidly. You wouldn't boil over though

Re: Swap early Radiator fan for late, wiring question.
Posted: 05 Aug 2017, 12:48
by marlinowner
Doing that would blow the fuse unless the resistor was fitted in series as well.
Re: Swap early Radiator fan for late, wiring question.
Posted: 06 Aug 2017, 08:49
by bmouthboyo
Got my old fan and cowling in at moment but it is pretty rusty and not a good seal around the edge of the radiator. Ideally I would like to get a late fan and swap over in the future.
Are the late fans much more powerful?