850 electric fan in 240

DCW242 · 2015-08-27T08:28:34+00:00

I used the 960 fan and a cut down 960 shroud. But I'm tempted to redo it, mounting the fan in the standard 740 shroud. I also used the Davies Craig sensor...

Ex850R

blondejay;106774 wroteThere is a flat head adjustor on the out side of the pressure switch, no need to remove

Which way is colder and what negatives are there?

deleted_user_160

I'm not entirely sure to be honest,
Though changing the pressure screw +/- will help the compressor cycle less and still maintain cooling.

shane1750

Hi
Does anybody know which Davis and Craig fan fits a 1990 240 ?

JamesM

Just get out your trusty tape measure. Most should fit although you may need cable ties to secure it.

DCW242

I did this conversion on my 740Turbo today.
Most of it is the same as doing it on a 240, there's a lot less room in a 740T though.
I decided to use the Volvo two stage relay this time, I took the fan and wiring out of my 240 a few days ago and found the connector had started to melt on the 30amp bosch relay, and I had the relay to go with this fan. The only disadvantage this is the 850 relay is activated by earthing the trigger wires, to stop the fan from coming on after the engine is off I had to install a very small relay under the dash to create a position 2 switched earth, this connects to the switch, and the other side of the switch connects to the relay.
I fitted a 240 relay bar under the left hand headlight, I kept the 240 distribution bar so I can add some unrelated relays later.

For the switch I used a bmw 3 pin 80/88 switch, in the lower hose with a adaptor. I'm not sure what it came out of it, it appears to be the same as the saab one but it has a much smaller thread the same as the bmw switch. A saab one can easily be used with a thread adaptor. This is only a temporary switch for this car, I have a 531 head I plan to fit and it has a spare blanked off fitting I'll use for a switch/sensor.

Studs and nuts replaced with bolts:

850 fan fitted to the 740T shroud, I had to mount it much closer than I did on the 240 to give enough room between the pulley.

This is how it looks fitted. There's very little clearance in a 740T, about 5mm between the fan and radiator core, and about the same between the pulley and the fan motor.

DCW242

@vo940

Ex850R

Gimme that pulley and my mate will make it shorter and some studs to fit it in....

DCW242

Ex850R;c-145824 wroteGimme that pulley and my mate will make it shorter and some studs to fit it in....

It bolts directly onto the water pump pulley, there isn't much room to modify it.

Ex850R

Doesn't need to be that big, me mate is good at making things simple! If you have spare bits, he can machine them or make new suitable bits, he owes me a favour...

egads (she/her)

A 360 water pump has a shorter snout so grab one of them and adapt the pulley and you will gain almost 2cms

ramrod

What is the advantage of putting an electric fan on a car that already has a clutch fan? More load on the alternator?

DCW242

ramrod;c-145831 wroteWhat is the advantage of putting an electric fan on a car that already has a clutch fan? More load on the alternator?

Less load on the engine, it's a lot quieter, and it doesn't run when there's no need for it to. the car has a 100amp alternator which can handle it along with other upgrades without any problem.

Angus242164

For anybody not wanting to mess with radiator hoses and sourcing switches and adaptors, an alternative is to use an adjustable temperature controller module.

I used one from Jaycar years ago on my 760 Turbo, the kit came with thermistor bulb on a wire (not an automotive grade item) but I found that the temp/resistance range of a Volvo coolant temp sensor was almost the same, and fitted that to the head as the temp input. From memory the sensor was for the CIS system on a B28E 760GLE but I would need to confirm.

The module operates a relay, and offers a high degree of adjustment, so I was able to keep the temp gauge free of fluctuations.

It was 100% reliable over many years and well over 100,000km. It was a kit that requires soldering together and cost $40 or so but there are probably cheaper pre assembled ChinaBay versions available these days.

DCW242

Angus242164;c-145848 wroteFor anybody not wanting to mess with radiator hoses and sourcing switches and adaptors, an alternative is to use an adjustable temperature controller module.

I used one from Jaycar years ago on my 760 Turbo, the kit came with thermistor bulb on a wire (not an automotive grade item) but I found that the temp/resistance range of a Volvo coolant temp sensor was almost the same, and fitted that to the head as the temp input. From memory the sensor was for the CIS system on a B28E 760GLE but I would need to confirm.

The module operates a relay, and offers a high degree of adjustment, so I was able to keep the temp gauge free of fluctuations.

It was 100% reliable over many years and well over 100,000km. It was a kit that requires soldering together and cost $40 or so but there are probably cheaper pre assembled ChinaBay versions available these days.

That sounds like a good way of switching it and keeping it tidy, another option is to fit the bmw type switch directly into the head if there is a spare fitting available for it. The Switch I used has a 80° and 88° on, I used the 80° in the lower hose and it works perfectly, it comes on at the right temp and only runs for 10-15 seconds. The 88° is probably more suitable for the hot side of the system though.
I'll update once I have the new head fitted with the switch in it.

Those sensors were used for B28E CIS on 760s, I noticed they were a different part number when fitting CIS to my 260s.

240

I've been running my e-fan for over a year now. The only issue I have is that it actually keeps the engine a bit too cool; the needle usually sits between 1/4 and 1/3 up the gauge.
I suspect this may be a combination of the fan running more than it needs to, and the thermostat being open more than it needs to, but I'm not 100% sure.

The temp switch is an 82°C one, in the lower hose and I'm running an 87°C thermostat.
I'm wondering if maybe I should try and move the switch to the top hose, or keep it in the bottom hose and try an 88° one?
I think I wired up the fan to use the high-speed setting, I could try changing it to the low speed but then that may not provide adequate cooling...

DCW242

240;c-145854 wroteI've been running my e-fan for over a year now. The only issue I have is that it actually keeps the engine a bit too cool; the needle usually sits between 1/4 and 1/3 up the gauge.
I suspect this may be a combination of the fan running more than it needs to, and the thermostat being open more than it needs to, but I'm not 100% sure.

The temp switch is an 82°C one, in the lower hose and I'm running an 87°C thermostat.
I'm wondering if maybe I should try and move the switch to the top hose, or keep it in the bottom hose and try an 88° one?
I think I wired up the fan to use the high-speed setting, I could try changing it to the low speed but then that may not provide adequate cooling...

I had an 88° switch in the lower hose of my 240 with it fitted to the high speed side of the fan, it would get a little hot before the fan would come on, but only a few mms on the gauge. Having used the lower speed on the 740 it seems to work well, it moves enough air to cool it down quickly and it's much quitter. I was working on a P80 V70 a few days ago with the same fan and it seems to only use the low speed for normal operation. I think a slightly lower temp switch in the lower hose and running it on the low speed will work well on the 240, I plan to fit an 88° switch to the new head and rewire it to the low speed.

240

I might try that then, because you're right about the high speed being very loud.

I assume that it should technically be wired up so that the high speed kicks in when the AC is turned on, but I never see temp increases when using AC so I guess it doesn't matter too much.

DCW242

The low speed has worked very well on my 740T so far, but I only drove it once last night and this morning. I haven't tested the AC yet since it isn't connected. I will probably use the low speed for the AC as well, and the high speed I will either not use or connect to an over heat switch, the radiator already has an overheat switch in the top right I could use to switch the higher speed, and remove the factory push fan at the front.

240

I've wired mine so that there's a switch in the cabin to manually turn the fan on, maybe I should make that switch operate the high speed and the thermoswitch operate low speed.

Vee_Que

My 122 runs the programable Davis Craig unit with a probe, it's very reliable with my electric fan.

I usually convert the water pump pulley to bolts when going electric to gain room.

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