Disassembling viscous fan

[MattF]

Well, it survived a run to Skegness and back yesterday. Factory water
temp gauge stayed rock solid, thermo' housing water temp gauge stayed
around 83 degrees constantly, rad temp gauge, (sensor bolted to side of
rad just above shroud mounting point), stayed under 60 degrees. Did as
you suggested Vince, and just switched the fan on for speeds under 50 mph,
and she ran like a dream there and back. Didn't overly push her as I did
notice early on that there was some slight contact, (removed paint from
back edge of fan motor), between the water pump spindle and the back of
the fan motor, so kept her under seventy with no extremely rapid acceleration,
just to be on the safe side. Other than that, it worked to perfection.

Now I just have to whip the assembly back out so that I can space the motor
away from the shroud assembly slightly, just to give a bit more clearance
between the motor and pump. All in all, though, quite chuffed. When I take
it out I'll take a proper picture of the new fan assembly, so that you can see
what it looks like, rather than the partial engine bay shot.

[BUSHWHACKER]

Lovely jubbly!

[POPEYE]

Well done!!! looking forfard to the pics.

[MattF]

Took some pics whilst I've got it out to enhance the motor clearance. On the
first pic, you can see where the front of the water pump has just slightly
scoured the back of the motor, just to the right of the left hand mounting lug.
The last picture shows two nuts on the mounting bolt to try and get some
spacing between the motor and the shroud, but I've changed those two nuts
to one nut and two washers. Two nuts didn't leave enough of the bolt protruding
through for fixing. The rest of the pictures are just various angles, and one
of the unit completely assembled. (The wifes been shaking her head at me
taking pictures of it. Women just don't understand. ) The spacing nut and
washers have given about an extra 5/16 clearance, which I'm hoping should
be enough.

[MattF]

That extra 5/16" clearance seems to have made all the difference. Taken
her out and given her some stick today, fast acceleration, high revs going
up big hills as fast as possible, and there's no sign of any more contact
between the water pump spindle and the back of the motor. Water temp
stayed under 90 degrees, and rad temp under mid 50's. So, it would appear
to be working okay now. Just got to find out now what that annoying blo*dy
rattle behind the dashboard is at certain revs. So, for reference, if anybody
is thinking about rad mounting an electric fan, just try to make sure you have
approx. 1/2" or above clearance between the water pump and the back of the
fan assembly. Have also found out that running the fan for approx. five mins
after turning the engine off gets the rad cooling down nicely instead of the rad
temperature rocketing. Just got to get a timer circuit sorted for automatic timing
on that side of things now. I know this was mentioned in another thread a while
ago, but does anyone know offhand which wire on the alternator goes live only
when the engine is running?

Cheers.

[POPEYE]

Seems to be working ok mate, I would have liked to get the AC fan "running on" after the ign is turned off, as it is i have to sit there with the ign back on to let the fan cool her down a bit, bit of a nueisence really, I got an email from Simon O (new Zealand) with his mod to accomplish this but he reported that although it worked on the bench it would'nt work on the truck as it was picking up a "ghost Earth" from the AC so back to square one! Your idea seems to be the answer. Ian

[MattF]

Do you have any more info on Simon's theory, Ian? You've piqued my curiosity
now.

[POPEYE]

Do you have any more info on Simon's theory, Ian? You've piqued my curiosity
now.

If i can find it, (Should be in my emails) i'll post it, There's a pretty comprehensive diagam,

[MattF]

Cheers.

[POPEYE]

CONTROLLING THE ELECTRIC FAN FOR LNI30 SURFS

The basis for this fan to work is the wire from the Thermo-switch on the lower front of the thermostat housing.
TEST.
With the engine running pull this plug/wire off the sender and the fan should start.

The Electric fan / Auxillary fan / AC fan call it what you like has a bit of a strange factory set up that I could not quite figure out. So here is what I did.
It appears that the original switching is done by two things
1. AC turning on
2. The thermo sensor ( in lower front of the thermostat housing ) opening which removes an earth to the system somewhere. This is a good idea as it is “fail-safe” meaning that if the wire breaks then the fan comes on.
For a start my fan motor was shot so it had a free trip to the s$$$$ metal yard.
I replaced it with a fan out of a wreck we had in the yard which fitted into the existing shroud nicely.
Secondly it appeared that the wiring was faulty so out that came too.

I am an engineer and used to work on Aircraft so I have a bit of a thing for abbreviations and acronyms. In my write ups and diagrams here are the most commonly used ones.
ACFCU AirCon Fan Control Unit
T-Switch Thermo switch
T-Stat Thermostat
MCIS Manual Control & Indication System
OTWS Over-Temp Warning System
ELW Earth Loss Wire. This is the one from the t-switch and is the backbone of the whole project, it is worth using all new wire for this project as then you will know that it is all in good condition.

Now for the fun
As promised I will start with a really basic system and the full-monty that I have fitted.

If your fan works with the above described test then you can simply start here.
From the T-switch run a wire to a normally closed (N/C) switch suitably located and back.
Cut the ELW and attach this new wire.










Done ! You now have the most basic yet effective fan control.


From here you can progress to using a relay, just like wiring up a set of spotties, except that the relay is normally closed N/C instead of N/O.
You should figure out how and where to attach a wire that illuminates a lamp and there are many other features that may be added.

The system I have is in two main parts
1. The Fan controller ACFCU & MCIS
2. The Over-temp warning system OTWS

The diagrams were drawn by me so that I could understand them, some of the symbols may not be “stardard” electrical ones but I hope that you are able to understand them.

REMEMBER !
I designed this system as the wiring diagrams show and put it all together in my workshop and bench tested the whole lot prior to installation.
This is not difficult to make and install. If you can fit up a set of spotties then this is about the same.

MCIS
DESCRIPTION

This is the part that gives me control of and indication of the status of the fan
It also enables me to “override” the system temporarily during a hot start so that I get maximum power to the starter motor.
It works via momentary action switches and a latching relay that has its primary power from ignition. This is so that the system self resets when the ignition is turned off.

ACFCU
DESCRIPTION

This one is fairly self explanatory and you will note that a dioded input is taken from the AC compressor clutch positive feed.. This is so that when the AC is on the fan will run too.
When the T-switch opens the fan obviously runs and the green lamp on my panel lights up.

OTWS
DESCRIPTION

The overtemp warning system lets me know when the ELW has opened, indicating that the t-switch has reached temp ( mine is 92 deg) the alarm sounds and the red light that is fitted beside my second temp gauge illuminates.
The alarm can be silenced but the red light stays on until the switch cools and resets/closes. Mine must go to 88 deg before closing again.
There is also a test function so that I can see if the lamp and alarm are working.

Hi Matt, I cut and pasted the above from Simon O's email to me but for some reason the drawings have;nt copyed, Dont know if the site's deleated them
(due to size) or what! Also tried a straight from attachments but that did'nt work either due to size, Only thing i can think is if you PM me your address i'll post a copy of the documents to you, Ian

[MattF]

Do you think I'm becoming a cooling fan obsessive?

Been doing some more testing with the fan, and have found out that the
Surf cooling system, when in good working order, actually needs very
little assistance from a fan. Been running round yesterday and today, typical
short stretches of road where you can peg it a bit, junctions, long uphill
stretches, and over the last two days, (weather been cool and rather damp ),
haven't actually used the fan at all. All the runs have been between about
five and ten mile long, but she's held her own without me using the fan. Rad
temp has still never gone above sixty, (until stationary and engine switched
off), water temp has stayed below ninety. I kept reaching for the switch but
managed to resist. Anyhows, getting back to the point, , have found out
what one of the side effects of keeping the engine too well cooled can be.
When water is passed to the expansion tank during running, if the engine is
kept overly cooled, around eighty, it doesn't tend to suck the coolant back in
from the expansion tank when the engine cools down. It appears to affect the
cooling system vacuum setup. Just thought it might be worth mentioning.

Also, I don't know if I'm imagining this one, but without the drag/weight of the
viscous fan assembly, the gear change point seems to have altered ever so
slightly. Seems to run slightly higher on revs/speed, before the gears change.

Edit: Also, forgot to mention, I'm gonna' be attempting to make a sensor/switch
hose adaptor for the top hose. Have all the bits now, just need to assemble the
devil, so within a few days, I'll hopefully post some pics that will make John
Noakes look like an amateur B.P bodger.

[MattF]

Just popping up a pic of the hose adaptor I've made. No knobbly bits
on the ends for the clamps, as it's 38mm pipe, so should be a tight fit
anyhow. 80mm long, brass pipe with copper earth strap, and a genuine
Toyota thermo switch, (out of a Corolla). Fittings for the switch are made
from a bog standard 15mm endstop compression plumbing fitting, with
the endstop drilled out and tapped with a 5/8 un(f|c) tap.

[POPEYE]

Just popping up a pic of the hose adaptor I've made. No knobbly bits
on the ends for the clamps, as it's 38mm pipe, so should be a tight fit
anyhow. 80mm long, brass pipe with copper earth strap, and a genuine
Toyota thermo switch, (out of a Corolla). Fittings for the switch are made
from a bog standard 15mm endstop compression plumbing fitting, with
the endstop drilled out and tapped with a 5/8 un(f|c) tap.

Nice job Matt, It looks like an oil supply tank i made for the Yamato, to drip feed oil to the four propeller shafts If i remember this is to take the sensor for the fan set up you installed? (sorry i've slept since i last read through this thread),
The expansion bottle anomily you mension, is that gonna be a problem? It's just i would'nt have thought 80% was over cool, When mine get's to over 80
i start reaching for the AC fan switch Ian

[MattF]

Nice job Matt, It looks like an oil supply tank i made for the Yamato, to drip feed oil to the four propeller shafts

Cheers. Happen to have any pics of the oil feeder? Could be useful for some
of my other long standing projects.

If i remember this is to take the sensor for the fan set up you installed? (sorry i've slept since i last read through this thread),

I think Rip Van Winkle probably slept for less time than since I started this thread.
It is indeed, so that I have temp switching as well as manual switching.

The expansion bottle anomily you mension, is that gonna be a problem? It's just i would'nt have thought 80% was over cool, When mine get's to over 80 i start reaching for the AC fan switch Ian

Mid 80'ish or above seems fine. Couldn't say for definite that was the cause,
it may have been a temporary glitch, but initially, when switching the fan on
constantly at speeds less than 50mph, temp gauge stayed pretty much at 80,
and when I checked the expansion bottle, was past the full mark by an inch or
two, but water level needed topping up slightly via rad cap. Have now switched
to just using the fan when temp gauge starts reading mid 80's or above, and
coolant level seems to be fine under rad cap. Can't figure out why, but the temp
is the only difference I can attribute it to. Wasn't vast amounts that got left in the
expansion tank, but could bite one in the bum eventually. That's also why I
picked the temp switch from the Corolla, as they have an electric fan only. The
switch has 90b printed on the side, so I'm assuming that is the temp it kick's in
at, as obviously, kicking in before the 'stat opens could be pretty pointless.
Plus, if I actually had to buy a replacement switch from the dealers, (got a
couple of spares from the scr*pyard), at least I can stick with the normal
dealer for the Surf. Did also get a couple of temp sensors as well out of one
of the Corolla's, so might have a go when I've chance at matching a digital
meter to one of those as an extra temp gauge for monitoring something else.
Got both sensors, the three switches and a bog standard two wire temp switch
for a fiver. A bit of brass wadding, and they've all come up a treat and cost
practically bugger all. Christ, I do ramble on, don't I. Would recommend
leaving the fan off until it gets closer to 85-90 rather than switching on at 80.
I've been driving the Surf pretty hard over the last week using this method, and
the temp starts dropping fairly quickly back to 80'ish as soon as you kick the
fan in, but it does take quite a bit of stick to get it to the stage where it's getting
that warm anyhow. After a year of obsessive paranoia regarding watching the
temp gauge, it does seem pretty weird to find out how well the Surf does
actually cope without forced cooling on it's own, most of the time.

[POPEYE]

Yeah i suppose you have to give the original designers credit for knowing what there doing otherwise they would'nt have sold too many surf's if they were blowing up left right and chelsey its just with this ever present head worry and the age of the trucks you do tend to watch the temp like a hawk,
I had a scarry moment the other night, I went to pick up that decking (short M way trip) and she was running like a pig! something seem'd to be holding her back so i floor'ed it and the kick down come in and she accellerated quite well, after about a minuit of accellerating i noticed the temp gauge was near 100%, $hit myself and come off the pedal and flicked on the fan and she soon dropped backed to 90 ish, That was with an empty truck! On the way back loaded with decking and block's she ran fine, temp normal, dont make sense!! Guess she dont like being caned I'll post a pic of the tank in the ship, although it's just like your sender port except the ends are soldered up and theres an oil supply pipe from the bottom tee'd off to the four shafts,
What's your "other projects" Matt, not RC ships i suppose?, Went for ships as opposed to aircraft as there's less chance of totaling em, and less skill needed, Especially after a nabour spent months building this model spitfire,
he had a little trouble getting it airborne but no trouble getting it back down again, Pile of bit's Ian