Fan viscous coupling

A7RXY · March 10, 2010, 06:14:44 PM

I\'m waiting for Mazda to get back to me to see if these are still avalible, any idears what they cost ?
I\'ve been intouch with Tim at RX and he does not have any, I have emailed Jimmys but they are yet to reply. I\'ve had a look on the US sites and they appear to be very expensive and then there\'s shipping on top of that.
Has anyone got a working one for sale as I want to keep the car standard, or I will have to go the electric way.

syebba · March 10, 2010, 06:26:34 PM

Wait to hear from mazda,if too pricey,there must be a good 2nd hand one around surely.
ta stu...[kiwimazda is breaking 2 1st gens]

Ian65 · March 10, 2010, 08:25:51 PM

Dibs,
I\'ve got the viscous coupling off the B reg I stripped last week.
You\'re welcome to it for free if you want it.

The car wasn\'t running due to a faulty fuel pump so I don\'t know how good it is but Keith took the car off the road due to corrosion and I think the fan was ok then.
These were bloody expensive last time I enquired about one.
Electric is the way to go really, how many manufacturers fit viscous fans these days?

captainbizzaro · March 10, 2010, 08:31:34 PM

You\'re not a man until you\'ve had the skin of your knuckles removed by an over zealous viscous.

Ian65 · March 10, 2010, 08:36:03 PM

Quote from: captainbizzaro;678148You\'re not a man until you\'ve had the skin of your knuckles removed by an over zealous viscous.

Mine would have taken your fingers off when the coupler seized!
I should have sussed it when I bought the car and found 3 spare fan belts in the boot.

A7RXY · March 10, 2010, 08:37:11 PM

Cheers Ian I will take you up on that, do you know if they can be repaired ?

I\'ll PM you

Ian65 · March 10, 2010, 10:12:46 PM

The only realistic repair that you can do is to the RX7 coupler is check and free off the pin that controls the viscous coupler.
On the front of the fan is a bi-metallic strip that heats up and bows outwards.
Underneath this strip is a small brass pin which is usually pressed in by the bi-metallic strip. As the strip bends, it relieves the pressure on the brass pin allowing it to move outwards and this in turn operates the valve inside the coupler to allow the silicon oil inside the coupler to flow and work the coupler.

Sometimes, due to lack of use / age, this pin seizes in its hole and so the whole unit fails to operate, either being stuck open, closed or somewhere inbetween.

To check the operation of the pin, carefully prise out the bi-metallic strip from it\'s cradle on the front of the coupler and check that the brass pin moves smoothly and easily.
If not, polish it up and lubricate it then carefully refit the bi-metallic strip by pushing it back into place.
The strip, when cold, must be in contact with the pin and push it into its hole.
If the strip is heated with a hot air gun / hairdryer, it should bend and allow the pin to pop up from its hole.

If the internal seals have gone in the coupler and allowed the oil to seep out, it\'s time to throw it in the bin.

As your car has been laid up for a while, it might be worth checking this pin.

A7RXY · March 11, 2010, 08:19:55 AM

Cheers Ian, I\'ll chk it when I replace it with your one, did you get my PM ?

syebba · March 12, 2010, 08:56:42 PM

Quote from: captainbizzaro;678148You\'re not a man until you\'ve had the skin of your knuckles removed by an over zealous viscous.

Haha,well i\'m not a man yet, as i\'ve been lucky & avoided this dubious pleasure!:rolleyes:
No doubt it\'ll happen now i\'ve written/typed this post,must touch wood,does mdf count?:spank
ta stu...

stu aull · March 13, 2010, 07:41:38 AM

New ones $100 US regularly on US ebay for 81+ RX7s

Stu Aull
80 GS
Alaska

A7RXY · March 15, 2010, 04:26:36 PM

Ian, Fan coupling turned up half an hour ago, I took the old one off this morning and ran the engine with it off and the engine sounded completely different. I fitted the one you sent and the engine note had not changed from running it without the fan, I now realise how bad the old one was, as when working in the engine bay with the engine running how noisey it was and how windy.
Once again Ian thanks for your help and the part, so thats aleast 2 beers I owe you when we meet. Keep spinning.

Dibs

Ian65 · March 15, 2010, 04:58:51 PM

Quote from: A7RXY;679288Ian, Fan coupling turned up half an hour ago, I took the old one off this morning and ran the engine with it off and the engine sounded completely different. I fitted the one you sent and the engine note had not changed from running it without the fan, I now realise how bad the old one was, as when working in the engine bay with the engine running how noisey it was and how windy.
Once again Ian thanks for your help and the part, so thats aleast 2 beers I owe you when we meet. Keep spinning.

Dibs

you\'re welcome!
give it a good run though and get the engine well up to temperature to test out this coupling.
Most seize up and shred the fanbelts but sometimes they can go the other way and not spin fast enough / cool the engine enough.
Give it a good run to be sure in your own mind it\'s ok.

Just as a matter of interest, check to see how stiff the actuator pin ( under the bi-metallic strip) was on your old coupler.

When I had all the grief with mine last year, Keith advised me to go for a spin around the local lanes without a fan on just to see how much my faulty fan was loading the engine ( if you keep moving, you\'re ok the airflow cools it)
The difference was amazing, it revved up faster, and was altogether smoother and more responsive.
I was going to go electric after this but then got distracted buying the project car so I just ended up putting another viscous fan on my red car.

I know you want to keep the originality of your car but you could always put an electric one on and then keep the viscous fan in case you wanted to return the car to standard.
The braking effect these viscous fans have on the engine is immense.
I\'m going for electric on my black car.

A7RXY · March 15, 2010, 05:24:31 PM

I did strip the old coupling by removing the strip, but while the pin was loose, it stayed in the down position, I assume that it would rise when the strip bent upwards when heated, I tried a hot air gun on it but the pin stayed low, I can only think that what ever pushes the pin up must be stuck.

But I take your point with the electric fan, I look forward to see which one you use.

Dibs

A7RXY · March 16, 2010, 02:47:22 PM

Ian/Keith, you are both right. I took the Rex for a nice drive through the lanes today, as the sun was shining, and the car was a far better drive with the replacement coupling fitted, more responsive and far less noise, so it just goes to show how much power the fan in a stuck position takes from the engine............so big thanks.

Dibs