Fan control

Temp in what - coolant or air?

Either way, I'd be tempted to use a commercial t'stat rather than root around
with a temp_sensor/amp/comparator/relay_driver/relay or similar.

its a car . with a huge and expensive motor and radiator to which I wish
to add electric fans and removed the motor driven unit ( which uses
several hp)

atec77 wrote:


These are the devices you are after:

http://www.daviescraig.com.au/main/thermal_switches.asp?prodid=1

Andy

Many Thanks .

I have fitted EF thermofans in my NB Fairlane (yes there is at
least one such a model for anyone who thinks Ford totally
skipped from the NA to NC model)  and I successfully used thermo
switches from RS components/Altronics/Jaycar fitted to as l
shaped aluminium bracket riveted to the top of the radiator
surround. See my post son page 5, 6 , 7 onwards here
http://www.fordforums.com/showthread.php?t91%067&page=1&pp10%&highlight=thermos
and
http://www.fordforums.com/showthread.php?t11%1459&highlight=thermo
for details.  I can also email pic if you want to see what it
looks like (it is all hidden under the fan shroud).  They work
fine but the standard alternator has problems on very hot days
keeping up with the climate control these thermos and every
other add on that Fairlanes have.

http://www.fordforums.com/showthread.php?t91%067&page=1&pp10%&highlight=thermos

Its a  rare Jag  and I want to dump the HUGE finger chopper on the water
pump.. I will have a read and thanks .
  have some EB fans so lets see how things go

I have used the copper probe Davies Craig units on other cars
but found that, in addition to being much more expensive, they
can be problematic in terms of creating leaks where the probe
enters the radiator hose.  In a 1980 CM Valiant I once had there
was a spare plugged heat sensor switch hole in the top of the
radiator so I simply use a VDO temp warning light sensor/switch
that screwed straight in and wired it via a relay and that
worked really well.  Many cars have  spare temp sensor switch
holes in the radiator or thermostat housing and this is a neat
factory original look solution. The Fairlane had no spare holes
(lots of existing heat sensors/switches already installed).

I just ran some alloy pipe into an adaptor added to the top hose  with a
knub added and will dril and tap as needed..
  Tig is very handee

Ok the neatest cheapest solution then is drill a hole (or two
for the twin fans) in the top radiator tank and tig weld or
braze a copper nut onto the hole to take the required VDO temp
warning light switch. Use two of different temp settings so one
goes on before the other. Just have a browse in Malz, Supercheap
or whatever to get two temp warning light switches (low as
possible  temp setting if you are not brave) and buy he copper
nuts to fit. Then wire through two 60 amp automotive  relays
(Altronics/Jaycar).

see
http://www.siemensvdo.com/NR/rdonlyres/5D71B533-4F7E-407C-91A7-A80F47A402F4/0/svcataloguesensorsinstrumentationenv20.pdf

for VDO sensors

I'm sure you'll be fine then, but just for the record, I had a
metal probe fitted in where the top hose leaves the radiator
and the auto elec just used a bit of goo (silicone or w/screen
sealant I think) around it before tightening up the hose clamp.
Could be a problem if your hoses are too old and stiff, but
that can be a problem by itself. It's never leaked anyhow, and
that was ten years ago. The radiator's been out a couple of times.

I used a fan unit from Repco mounted on the front of the radiator
which is hidden behind the grille, so the engine bay appearance
is unchanged, except for the absence of the engine fan.

Clifford Heath.

Ive cut the hose , inserted some suitable alloy  pipe and drop a lump
with the tig then drilled and tapped it , added anti corrosive to the
water and I have a suspicion it might last a while :)
  I wont do anything to the radiator as it's worth about $800.00 and I
hope it will last forever .

Also see http://www.speco.com.au/gauges_ad.html for some ready
made hose adapters.

$800 not much for a radiator . . .but more than any Jag is worth !!

  Obviously Mummy and Daddy wont let you play with the others at
preschool ..