Electric fan for the V8, what is recommended?

Barten

Barten

Active Member
I plan to fit an electric fan to my V8. It is actually an SD1 engine in my car, and it has a viscous coupling fan. What is best; to have a blowing fan in front of the rad or a suction fan behind it?
Is it possible to fit one in front without having to modify the front valance, and what size can be used if so. Any preferred sizes and makes in general? Kenlove, revotec, others? What is the experience with electric fans, does it influence much on power output? I'd love to hear from you who have done this mod.
regards, Barten
 
rockdemon said:
If you have an sd1 viscous fan and it fits wouldnt you be better off using that?
Click to expand...

My thoughts exactly Rich. Keep it simple.

However, if you are certain you want to go down the electric fan route then there are a number of threads on the forum on the subject of electric fans. Both testrider and Stina have neat installations so those threads would be a good starting point. If there is space between the front of the engine and the rad then a fan that sucks is always the best solution. Space on the P6 engine is restrictive but I'm not sure about the SD1 engine with the viscous fan pulley. Try to get the biggest (area) fan you can and one that will shift at least as much air as the original, otherwise you'll be urinating into the proverbial wind :wink:

If you are having cooling problems then it is definitely worth investigating the root cause prior to considering the type of fan to use. Again there are a number of threads on the forum that discuss this.

If your simply looking to liberate a few extra horses then IMO there are better options, such as fitting more free flowing air filters etc.

Dave
 
Hi Barten

I think you'll find that the viscous coupling (and water pump) that you have on the SD1 engine is too long to fit behind the P6B radiator.

An electric fan in place of the mechanical fan should give you around 6 bhp extra! With commensurate improvement in economy, particularely at higher revs.

There seems little doubt that Kenlowe have by far the best fan blade design. (compare with the blades on an A400M transport for comparison of best modern design) Beyond that, curved blade is definitely better than straight blade, ie shifts more air for a given blade diameter.

Almost everyone seems to mount their fans in front of the radiator - ie pushing the air through it. This often requires a notch to be cut in the horizontal lip of the undertray to accomodate the motor in the centre of the fan. Most people seem to use 14" fans as the best compromise between covering the maximum amount of radiator core, availability and cost. I'd want the fan power consumption to be around the 200W mark as a rough indicator of how much air it is going to shift.

Control is best done either with a revotec thermostat cut and shut into the top hose, or a modern radiator sensor soldered onto the radiator hot tank. Kenlowe style capilliaries, either lodged in the radiator fins or stuffed under the top hose attachment onto the rad are now well past their sell by date, although still common.

Have a look at Stina's thread for more info and pictures:

http://www.classicroverforum.com/viewtopic.php?f=5&t=12365&start=120.



Chris
 

Attachments

  • DSC03851A.JPG
    DSC03851A.JPG
    127 KB · Views: 1,334
Hei Barten,

Is the viscous coupling working, or is the engine overheating?

By the way, where in the country are you?

Cheers

Tor
 
Hi Barten .
I fitted a pacet 14" blow through fan in the end . Be careful of what you buy , most blow through fans advertised as pusher fans work by reversing the polarity of the motor . When you do this they do indeed run backwards , but due to the design of the blades they actually don't move any air . I sent two back to two different suppliers and pointed this out , they both refunded without quibbling but still a hassle of returning them . The Pacet is a proper pusher fan . 14" is about the biggest that will fit without clearance issues with the bonnet catch , striker plate .
I have mine working from a revotek thermostatic controller in the top hose , also a manual override switch on the dash .
Also worth considering an expansion tank so you can keep the rad permanently topped up .
Tried to post links of the fan and controller with no success , but read about half way down this page and follow the links to fan and controller .
http://www.classicroverforum.com/viewto ... 5&start=45

Edit again , about quarter of the way down ,two links in the same post .
Hope this helps
Stina
 
Thanks for good replies. I have a modified 3 layer rad on my car, no clearance issues with the viscous fan, but as for overheating I can't tell. This car has been a project since I bought it in 1989. I had a quick blast in it before I started to dismantle it, but not long enough to find out about overheating. I might very well see how it works with the viscous coupling. Hopefully the engine will be running again this year. The project has seen some progress lately. To Tor; I'm in Averoy, Atlantic Road country.
Regards, Barten
 
Viscous coupling is the ideal solution i think as if it works it has most of the efficiency of an electric fan, and if it goes wrong (i.e. the clutch seizes) the fan still works just on full pelt so you dont overheat the engine when it happens!
 
rockdemon said:
Viscous coupling is the ideal solution i think as if it works it has most of the efficiency of an electric fan, and if it goes wrong (i.e. the clutch seizes) the fan still works just on full pelt so you dont overheat the engine when it happens!
Click to expand...

Unfortunately, most of the time they don't lock up when they fail, they do exactly the opposite and just coast, so you see it spinning and think it's working, but it isn't.
 
When they lock up and spin are they just running at engine speed ? If so where is the advantage over a mechanical fan in a traffic jam ?
 
The mechanical fan should be adequate at idle - the point is it doesnt waste power spinning the fan at 5000rpm when the engine is up there...
 
Barten said:
I'm in Averoy, Atlantic Road country.
Click to expand...
Ooh :D You really, really should get that car running this year and take photos for the "View From the Windscreen" thread...

Meanwhile you should post pictures of your car. Couldn't find any... :(
 
When a viscous locks up it spins faster than it should and is common place to have blades taking a flying lesson, quite often through the rad or pipework :shock:

Varying views in the SD1 club but I have electric on mine which benefits from quicker warm up, quieter, more economic and is a lot cheaper than replacing the viscous :D
 
Sorry to resurrect a geriatric thread. I'm unsure of the current capacities of the thermoswitches. Do you use an external power relay? Looking at the beefy cables in the thermoswitch I'm guessing not.
 
I would not go the relay less route for a few reasons and one very important and less considered reason is that if you should wish to fit a manual override switch on your dash you will be plumbing around 15 to 18 amps of current and all the attendant voltage losses and risks that long runs of high current cable produce.
With a relay the high current wires are very short and the control current to the relay coil is very very low so you can place a manual on off switch any where you want or indeed you can use some other switching scheme for temperature set point with out the worry of high currents.

Graeme
 
You must log in or register to reply here.
Back
Top