I've started working on a 1987 series III Vanden Plas V12. The fan clutch is seized and I'm debating on putting in a replacement fan clutch and replace the original yellow fan, or take the opportunity to put in electric fan(s): Either just one electric to replace the mechanical one, or a set of twin electrics in place of the auxillary and mechanical fan.

Any strong opinions?

Depending on the manufacturer, the cost of the clutch and replacement fan (black rather than yellow?) could be between $175 and $300, so a fair amount that could go towards an e-fan setup.

If I go the twin electric fan route I'd want to keep the run-on option for after cooling after shut down. A drop in option would be great, but I assume it will take some customizing of the shroud and mounting system.

Thanks in advance, Paul

 

I've gone both ways on Jags (and others) and have been happy both ways.

Obviously, staying with the original set-up would be faster and easier. An hour labor and you're done. If that isn't a consideration, I'd go with e-fans and enjoy the advantages. Get high grade e-fans. Some of the brand-x types don't last very long.

Cheers
DD

 

Mine all run E-fans, and have done so for a very long time.

I wire the RH to thermo, using the OE switch in the water pump inlet to switch the earth terminal of the dedicated relay.

The LH is purely A/C, and runs whenever the compressor is running. I looked at a/c pressure switches etc etc, but simple moved on and left it as I have it, and no issues since 1996.

The fan set up I used is from an AUSSIE Ford Falcon, and slide straight in as if made for the car. They are all over Ebay.

I have done many over the years.

I would never go back to the engine driven system.

 

Hey Grant. Friendly kiwi here. Does changing to e fan change any characteristics of the engine? Less 'roar', better revving, fuel useage etc? Just curious at the moment

 

YEP.

NO noise, as in the roar.

Faster warm up.

I reckon a crisper rev up, but then that could be juat me, and JD.

Fuel usage, NO idea, I drove the ring off it mostly, but we did average 11.2L/100km on the road trip around OZ, so not bad in my opinion, but in fairness, we never did either of those trips with the engine fan fitted. That fan exploded at very high speed, and vented the bonnet not long after buying the car, so the E fans were done very early in the ownership.

I also removed the front V of the crank pulley pack, so the less weight made if rev better of course.

All in all it was a sensible alteration that suited me then and now.

 

My lump has had two Efans since it's rebirth. It's GM PCM controls them by sensing temperature. It fires them one at a time if the temps go up. usually dormant if the car s moving at any speed. They were an aftermarket package intended for a middle aged Ford Mustang. Nice shroud included. Mounted a bit oddly, but work.


I am pleased.


When I was going to sell the yellow fan, I noted multiple cracks at the blade roots!!!! I tossed it, coupler and all.


Carl

 

FWIW...


In the various cars that I've converted to e-fans I've never noticed an improvement in fuel economy. Not saying it can't happen, but I've never seen it personally.


Cheers
DD

 

The subject of converting to e-fans is always being thrashed in my other car hobby (old Corvettes).

A basic misunderstanding on the subject is over how much energy one fan type consumes vs. the other and how. There's nothing magical about efans that makes them inherently more efficient than a standard clutch fan. They do not 'free up' HP as is commonly thought as the energy previously transmitted via the fan belt and pulley directly to the fan is now simply transferred as a higher load to the alternator. Nothing is really gained as converting mechanical motion to electricity then back to mechanical motion is pretty inefficient.

Another misconception is the amount of drag caused by a clutch fan. Many sources erroneously report it as being in the area of 10HP which of course is nonsense. I managed to get my hands on some GM documentation which indicates real life numbers in the 2HP range.

This is not a vote in favour of one type over the other, just some additional points to consider.

 

True.


Not always that easy.


1. Even when the clutch fan is on coast, it does soak up some HP.


2. When the E fan/s are active, they do consume HP!


3. But, most of the time, the Efans are dormant and don't consume HP!


Will one feel a difference. Naah, probably not. Measure a discernible one. Possibly, with advanced tech.


Carl

 

1. the amount consumed under those conditions is in the tenths of a HP. Kinda like a window fan on 'low'.

3. typically the total electrical draw of efans is more than the alternator puts out while at low and idle speed conditions where the fans are required the most. This puts the battery under a debit condition. Although the fans might soon turn themselves off, the alternator is chugging away for a while recharging the battery.

 

Yup !


1. Keep it moving, away from slow traffic. lesson from olden days. No fans attal on Hot Rods!!


2. A bit off subject, but the 140 amp alternator of my LT1 handles 'em easily. Older 65's and less, probably not so much.


Now, my 94 Jeep is old tech updated sorta. Ancient design 4.0 OHV six with EFI!!!
hard at work pushing a big Grand Cherokee medium sized SUV. No electric fan???
Viscous coupled. Drive belt sorta between the skinny belts of old and the broad serpentines that were available at the time. Works well???


More ways than one to skin a .....


Carl

 

one less belt to fry ♫

 

I'm using a 2-speed Ford Thunderbird fan assembly in my dads 86 XJ6 build. The PO put a universal type 3-core HD circle track radiator in it...no idea where it came from but its stout. The fan fits well on it with the V8 conversion. I could have built a few different styles of controllers for it but opted to keep this one simple and go with a Volvo 2-speed control relay .

 

Does the belt not also turn the water pump?

 

NOPE.

The "Fan" belt on the V12 is the front one the 4, and it ONLY drives that fan.

Thats why I removed the front V from the crank pulley pack when the E fans were ftted.

 

Thanks for the responses. Living in a hot climate my main goal is maximum or fully effective cooling. I assumed any horsepower improvement would be negligible. Some of the twin fan setups I've looked at do draw 25-29 amps so I need to check the health of the alternator and batttery. In limited running it's measured under 13 volts with the engine running and a/c on.

For purposes of looking at a twin e-fan setup, does anyone have the dimensions of the radiator core for the V12 radiator? I'm away from the car at the moment, and it's difficult to measure in situ. Would it be the same size as an SIII?

Thanks, Paul

 

You might need an alternator upgrade. Your '87 probably has the 65 amp alternator....which is a bit under-specified to begin with (as you know from your voltage reading). It was 1988-89 that Jaguar starting using higher output alternators




Should be the same as the XJS V12 radiator.....if that helps at all. Maybe an XJS owner who knows the measurements will happen along.

Cheers
DD

 

Winston,
call Retro Air in Texas and talk to Rock Browning the owner. He has electric fans for Jaguars, complete kits, he should know what you need.

Classic Jaguar Air Conditioning Kits, Upgrades | RetroAir, Inc.

I do not have any experience with removing the fan and clutch in any Jaguar, but it would seem to me that removing the load and weight off the water pump would be an improvement. What you need is to find a twin electronic fan assembly that is thermostatically operated, with relays to ease the electrical load. Shouldn't be that difficult to achieve.

 

He,he1


Due to a "me" mess up, my lump has an electric water pump as well. So, if I lost the serpentine belt, I could limp home, sans alternator and power steering!
Oh, and no AC. but, at present, It is dormant anyway.


Must be some reason that most if not all modern cars have E fans, huh?


OTH, viscous units are tried and true.


Some even do well with flex fans.


I forgot if the huge fan on my old Scout II was viscous or fixed. No viscous on the Toyota vintage FJ 40 Land cruiser, though!!


Carl