Electric fans and the Mechanical fan clutch (Aisin wins!!)

AliK

Vehicle Dating Officer
Staff member
Club Member
Very tempting!!!! I am a little fed up of messing about with it to be frank - but this is a last attempt!
 

AliK

Vehicle Dating Officer
Staff member
Club Member
OK, so just been out for a quick one and sadly ran out of fuel about a mile in !!!! I need to pull the new sender and work out why it’s sticking at 3/4 - I suspect that last kink I didn’t fashion into a Z shaped one is the issue (it was a Datsun 510 one I modified to fit). At least now I don’t have to drain the tank to do it!

EF8B05FC-744B-45ED-8B73-DC055E84E818.jpeg


But on the upside, when I got back home, after a neighbour rescuing me with a Gerry can, I left it idling for 10 mins in the garage which normally would pull the gauge well past half way. Well this time it only made it 1/3 of the way across and it wasn’t moving any further. So at least it seems my heat challenges are looking more resolved but I need to do this again on a hot day.

The Aisin appears to be constantly engaged as it feels just as vigorous cold or hot! Let’s let it heat cycle tonight and see how it does tomorrow morning.

But at 1/2 speed due to my crank pulley, even if fully engaged it’s still the equivalent of 1/3 speed on a normal sized crank pulley and I can’t hear it. So it shouldn’t be costing too many ponies if I choose to live with it! ;)

There is a nice bit of airflow if I put my hand on the front of the radiator, but there is an ENORMOUS dead spot in the middle of the fan, for obvious reasons!

I still will go for pusher fans just to have that insurance policy!
 

Joey Bratten

Forum User
Thanks Joey, that is very interesting indeed! I “think” I recall seeing that the same fan clutch goes into many different Nissan models and the Silvia was one of them, I could be wrong - but a bit of Rockauto-ing would soon prove it.

So, my 30 mins job of swapping fan clutches turned into 1.5 hours - must be getting slow in my old age! I had forgotten how tight the access to the bolts was but also the flange on the Aisin is 2mm less deep than the old one, which made the fan blades juuust touch the bolts on the ATi damper - so I had to re-install the fan again with more spacer washers added. In effect I did the job twice ;)!

In short, the Aisin is in and appears to centre the fan FAR better than my last one, showing zero discernible off centre wobble. Being kind to my neighbours at 22:00, I didn’t warm the car up but at a fast idle, it’s way more engaged than the one I took off. I can’t stop it with my fingers - the other one took no effort at all to stop, so that bodes well.

When the engine bay started to smell of toffee, I realised that I had spilled on the exhaust manifold my “poorly balanced on the cam cover sugary cup of tea” ! ;)

I’ll warm the car up properly tomorrow morning and report back.

If the fan clutch is the same, you can purchase these fan blades, which pull much more. Could be worth a try.

GKTech Fan – Slide Motorsport
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
If the fan clutch is the same, you can purchase these fan blades, which pull much more. Could be worth a try.

GKTech Fan – Slide Motorsport


Good link.

The issue for me would be that a stronger fan will take more power from the engine even when it's not needed.

You drifting guys have lots of power and do short runs with a fair amount of 'standing' time so you need a powerful fan that's 'on' most of the time. Correct?
 

Joey Bratten

Forum User
Good link.

The issue for me would be that a stronger fan will take more power from the engine even when it's not needed.

You drifting guys have lots of power and do short runs with a fair amount of 'standing' time so you need a powerful fan that's 'on' most of the time. Correct?

It's pulling more air due to efficiency, its not changing the force as its the clutch mech that is the limiting factor of that.

That's true for competition but practice and stuff we run continuously and are only limited by cooling tyres down, so we just need to most efficient cooling which is often the viscous fan.
 
Last edited:

AliK

Vehicle Dating Officer
Staff member
Club Member
So gang, the cleaners came just as I was planning on sitting at the laptop, so i had to leave the house and socially distanced myself in the garage

Fixed fuel sender so that the float is now pointing left instead of right!


F3975310-4C6F-4999-9B1A-0F5B9E8FC78C.jpeg

Filled up with an eye watering £80 of Esso 99 then went for a drive.


DA7F4FA3-218C-445A-BA13-6586331CCE35.jpeg
With the fuel sender showing F now, I gave the car a bloody good thrash and then sat in a lay-by idling for 10 mins. Normal driving, temps at 1/4 across, idling in lay-by, doggedly stuck to half or very slightly below (which is 85c I believe). Then I turned the engine off for a couple of mins and let it heat soak, started up again and gauge was just past half way. In under a minute, it came back down to half! Ambient temp today is 17c here. Would be interesting to see if it does the same at 25c.

The good news is, when I got home, it was back down to 1/4 and I could stop the fan with my fingers without having them chopped off!! So the Aisin is definitely working per spec!!! Yay!!!! Thanks to the gents who recommended it, it’s the first time in my Z ownership with a fan clutch that works as it should! It does however idle with a little more vigour than my other one, so there is noticeably more airflow through the rad.

Now the electric fans have become less of a priority and more of an insurance policy! I feel we should change the topic of this thread to make it more useful for anyone else for someone searching for a fan clutch in the future. Maybe it should be “electric fans and the mechanical fan clutch” or something!
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Is sucking hot air out of the engine bay much more efficient than blowing cold air in?
I get the theory, just not sure how effective it is.

I never replied to this sorry! Every time I have been studying / researching air cooling in closed environments, the overwhelming consensus is that negative pressure is always better - be it houses, pc cases, electronic enclosures or in this case the engine bay.

Also, blowing cool air isn’t going to be quite cool air once on the other side as it is still going through a rad with water at 90c or above. Assuming of course that the engine bay air is cooler than the water in the rad, you are still cooling the rad by reversing the fans and not letting the rad just bake the under bonnet with it’s heated water inside.

All of this is of course theory and once I hook up the two temp sensors, I can do trials with and without fans reversing to compare reality v theory! ;)
 

Farmer42

Club Member
Glad you managed to get the temp issue relatively sorted. I tried a combination of clutches & fans at the weekend and also managed to get mine to an acceptable situation. I, like you had forgotten how fiddly it is to bolt up a fan to the water pump so there were a few choice words and some scraped knuckles.:cuss: You were a brave man trying to stop your fan with your fingers.:EXTRAeek:

I ended up with my old S30 OEM clutch which spins freely when cold and stiffens very slightly (but not much) when hot together with the 280ZX fan. It was a lot quieter but moved up to temp quite quickly from cold and stayed around the 1/2 way mark. The S30 fan was no use as it fouled my P/S idler pulley (the 280ZX fan blades sit slightly further out from the pulley). As with you, I just need to keep an eye on it in really hot weather although having changed out my thermostat for one that opens at a lower temp may help (was 88 & now 85 degrees).
 

Paul_S

Club Member
So gang, the cleaners came just as I was planning on sitting at the laptop, so i had to leave the house and socially distanced myself in the garage

Fixed fuel sender so that the float is now pointing left instead of right!


View attachment 44579

Filled up with and eye watering £80 of essso 99 went for drive.


View attachment 44578
With the fuel sender showing F now, I gave the car a bloody good thrash and then sat in a lay-by idling for 10 mins. Normal driving, temps at 1/4 across, idling in lay-by, doggedly stuck to half or very slightly below (which is 85c I believe). Then I turned the engine off for a couple of mins and let it heat soak, started up again and gauge was just past half way. In under a minute, it came back down to half! Ambient temp today is 17c here. Would be interesting to see if it does the same at 25c.

The good news is, when I got home, it was back down to 1/4 and I could stop the fan with my fingers without having them chopped off!! So the Aisin is definitely working per spec!!! Yay!!!! Thanks to the gents who recommended it, it’s the first time in my Z ownership with a fan clutch that works as it should! It does however idle with a little more vigour than my other one, so there is noticeably more airflow through the rad.

Now the electric fans have become less of a priority and more of an insurance policy! I feel we should change the topic of this thread to make it more useful for anyone else for someone searching for a fan clutch in the future. Maybe it should be “electric fans and the mechanical fan clutch” or something!
I'm sure I paid a fair bit more than that for Esso 99 the other day!
 

AliK

Vehicle Dating Officer
Staff member
Club Member
Glad you managed to get the temp issue relatively sorted. I tried a combination of clutches & fans at the weekend and also managed to get mine to an acceptable situation. I, like you had forgotten how fiddly it is to bolt up a fan to the water pump so there were a few choice words and some scraped knuckles.:cuss: You were a brave man trying to stop your fan with your fingers.:EXTRAeek:

I ended up with my old S30 OEM clutch which spins freely when cold and stiffens very slightly (but not much) when hot together with the 280ZX fan. It was a lot quieter but moved up to temp quite quickly from cold and stayed around the 1/2 way mark. The S30 fan was no use as it fouled my P/S idler pulley (the 280ZX fan blades sit slightly further out from the pulley). As with you, I just need to keep an eye on it in really hot weather although having changed out my thermostat for one that opens at a lower temp may help (was 88 & now 85 degrees).

Thanks Paul and likewise, glad you’re mostly sorted. If yours does engage at all, then maybe a bit of an overhaul with silicone oil may fix it! Then again if it works .... ;)

@Paul_S - I couldn’t imagine anyone paying more unless on a motorway!!!! We regularly have fuel 3-5 pence per litre more expensive than anywhere else!!! :eek: How much are you paying for yours then?
 
Top