Thermo fan install question

[BAC]

Thinking about installing a thermo fan in 'pull' configuration and just wondering how much depth I have to work with.

In the pic below, if I remove as much of the existing fan blade mechanism as possible, can someone tell me whether I would end up at mark 1, 2 or 3?



Many thanks!

[GLENN 70]

Why would you want to do that .

[BAC]

Why would you want to do that .

A few reasons: quite often when I take the car out, I end up stuck idling in suburban traffic and some of the intersections around my place can take 3 minutes or more to get through.  In that time, the temp gauge goes from around half (where it sits when I'm moving) to three quarters or more.  I know the factory gauge is crap, but it is showing a significant  temp increase while sitting in traffic and I'd like to keep the old girl cool.

Another reason is the mechanical fan is not really needed when moving at speed, so there might be a HP or two to be gained by not having the blades spinning. Lastly, the previous owner had all the hardware for A/C plumbed in so there is a condensor sitting in front of the main radiator.  I have no idea whether the fan blades were changed at that time to help maintain airflow but it couldn't hurt to have a bit of extra assistance available.

[GLENN 70]

A HP or 2 ,well find it somewhere else . Are you using a shroud ,I couldn't tell in the pic . 

[BAC]

A HP or 2 ,well find it somewhere else . Are you using a shroud ,I couldn't tell in the pic .

Yes, have a shroud.  But what are the reasons for not doing it?  If it's in the name of maintaining originality, then that ship has already sailed.  There is an aftermarket A/C unit, radiator, air cleaner assembly, rocker covers, etc., etc. and I'm doubtful whether the fan blades fitted now are original Fomoco spec...

[GLENN 70]

No not because it won't be original ,I just don't like them .  Your going to have  messure from pulley face to radiator then check up the specs of the different brands .  Bigger and most powerful the better . You may have to upgrade the alt as well .

[mert]

Face of pulley will be somewhere between 2 and 3.   Depends on the thickness of the pulley face.  Say 1/3 the way back as a ballpark off the pic, as the pulley is usually thinner than the fan mounting hub.

[BAC]

Your going to have  messure from pulley face to radiator then check up the specs of the different brands .  Bigger and most powerful the better . You may have to upgrade the alt as well .

Thanks Glenn, please pardon my ignorance but which of the three marks in my pic corresponds to the pulley face?

From a quick bit of research, a single 16" unit seems to be the way to go.  Most of them are between 10 and 19 amps with higher CFM ratings as you move up the scale but the highest output ones are thicker hence my original question.

I will check out the alternator - it also looks relatively new and shiny so hopefully has more grunt than the original.

[BAC]

Face of pulley will be somewhere between 2 and 3.   Depends on the thickness of the pulley face.  Say 1/3 the way back as a ballpark off the pic, as the pulley is usually thinner than the fan mounting hub.

So if I understand correctly, the metal ring between marks 2 and 3 is the side view of the fan mounting hub?

And if you want you can pull the mounting hub off most WP shafts,  and even cut the end of the shaft to shorten it a bit.  Requires a press and removing the pump, and doing it carefully to not bugger up the bearings or seals.

Thanks for the info, but probably a bit beyond my skill level...    Plus by then the crank pulley would most likely be the limiting factor on clearance anyway as it is a 3 belt jobbie (alt, A/C and P/S).

[mert]

Between 2 and 3 is the side of your pulley.  The hub of the pump is under it.. random web photo below... the shaft extension will vary.



And yes, it is not a general home handyman job, just letting you know that if needed you can get some additional room with a bit of work.  You could just hacksaw it off too... 

[USA066]

Brian, unfortunately, I can say that I have been down this road in my 66. I have AC and PS, trying to keep it cool was a challenge if you remove the fan and spacer, this should give enough room at 2. If you are going to do this, it needs to be done properly. You need fans that pull at least 2800cfm. I had smaller than this, 2000cfm, and they just weren't up to the job.
Finding strong fans in Aus was a challenge, Craig Davies and some of the other brands weren't big enough and don't come with shrouds. I ended buying dual thermal fans from Old Air Products in the USA. These were 2800cfm and fit a 24" radiator. Not cheap but they are brilliant. It's all about air flow!
I can send more details if required, but depending on top or side mounts, cost is around US$250-300.
The other option is to simply install a push fan in front of the condenser, if there is enough room. I have found this to be very effective before I installed the AC.
Here is my setup. I am running a big radiator in my 66.
I didn't need to cut the shaft. Put 4 bolts in the secure the pulley.
Colin

[mert]

.. and be very careful with advertised CFM ratings.  Need to know how its calculated as many vendors fudge the numbers.  8000 cfm at 0.00001 in HG means nothing under operating conditions.  Need to know how its rated and at what condition.  A single rating also fails to indicate how a specific blade configuration will operate across its operating range (constant speed, multi speed, or variable speed). 

Same rating from two vendors may flow way different in the real world.  Same fan on two different cars may push very different flows as the radiators resistance to airflow, which varies, will dictate what the fan pushes at idle.  And tow fans that push "1200 cfm" may actually flow very differently under running conditions.

From SPAL "Note on Fans:  The rated CFM is highly subjective and is not always accurate.  Think of the current draw rating like a horsepower rating. The higher the current rating the more powerful the fan will be.  Regardless of the rated CFM."

[StephenSLR]

there is a condensor sitting in front of the main radiator

There's your problem; remove the obstruction and see the temps go back to normal.

s

[barnett468]

.
1. you will be EXACTLY at the 2 line if you remove the fan and spacer.

2. you will loose 7 mm when you install the bolts and lock washers to hold the pulley on.

3. the condenser has absolutely no affect in traffic or below around 20 kph UNLESS the ac is on.

4. as mentioned, do NOT buy a fan  based on cfm unless it is a spal or derale or maybe a davies . . buy it based on AMP DRAW . . If it draws less than around 30 amps, it is weak.

5. i was told that there are factory fans of old cars there that will fit . . the AU falcon might be one . . a factory fan will move a lot of air.

6. if you install a fan, you should install a fan controller for around 10 reasons . . these are the best.

http://www.dccontrol.com/selector.htm

7. as was mentioned, if you do not have a shroud, installing one will help greatly and.

8. if you have the big water pump pulley, installing the smaller one will help a little.

9. if you fan has 5 blades or less, it sucks . . a flex a .lite p/n 1717p will flow more air.

http://www.summitracing.com/parts/flx-1717p

10. you need at least a 180 thermostat.

11. if your fan is more than 30 mm from the radiator, you are mainly sucking the air from between the blade and the rad . . you are sucking less thru the rad than you could.

12. if your ignition timing is too low, it will tun hotter than kit should.

13. If you use waterless coolant, get rid of that crap . . it will run hotter with it.

13. Any other questions?
.

[BAC]

9. if you fan has 5 blades or less, it sucks

Or in this case, doesn't suck enough!

13. Any other questions?

I wouldn't dare... 

Thanks Mike, comprehensive but concise as always! 

[barnett468]

.

I wouldn't dare... 

Chicken!

Or in this case, doesn't suck enough!

Well....yeah . . it sucks big time because it doesn't sick big time..

Thanks Mike, comprehensive but concise as always! 

That would be comprehensive AND concise. 

[GEOFF289]

You have some of this forum's experts helping you already so not much I can contribute.

Nevertheless, regardless of what else you do, I reckon the first thing you should do is get one of these http://enginewatchdog.com/tm4.html to tell you what is actually happening temperature wise. As you say the gauges in our cars are not all that useful, and I wouldn't be relying on what looks like a 50% rise in temp idling in traffic - half way to three quarters - being anything of the sort.

My 66, which of course has a smaller radiator surface area than later models, can maintain its cool with a standard width 3 core brass or whatever (not alum) radiator, shroud and 7 blade engine fan with an aircon condensor in front of it. The engine watchdog generally shows mid 60 degree C temps (these are block rather than coolant temps) but on the hottest day and thickest traffic with the air running it gets up into the mid 70's. I think I have the alarm set on 80. It's never gone off. While all this is happening my dash temp gauge can be all over the place.

If you get one of these and it indicates you do have a cooling problem you can look at a thermo fan but if your radiator and water pump are good a shroud and more blades on your engine fan may well address it satisfactorily.

[BAC]

I reckon the first thing you should do is get one of these http://enginewatchdog.com/tm4.html to tell you what is actually happening temperature wise. As you say the gauges in our cars are not all that useful, and I wouldn't be relying on what looks like a 50% rise in temp idling in traffic - half way to three quarters - being anything of the sort.

Point taken - I'll have a look into that gizmo.

if your radiator and water pump are good a shroud and more blades on your engine fan may well address it satisfactorily.

Did some measurements this morning and it turns out fitting a thermo fan would be a bit of a tight squeeze without significant mods, so that idea goes on the back burner for now.

Once I have a better idea of what  temps I'm dealing with, I'll look into a better set of fan blades if I still think I need extra cooling.

[barnett468]

Did some measurements this morning and it turns out fitting a thermo fan would be a bit of a tight squeeze without significant mods, so that idea goes on the back burner for now.

Once I have a better idea of what  temps I'm dealing with, I'll look into a better set of fan blades if I still think I need extra cooling.

if you are talking about a thermal clutch fan, it is a waste of time and it will in fact run HOTTER with one because they do not spin at the same speed the pulley does . . they spin slower when fully engaged.

.

[anfo99]

I have a 16" fan on mine that I bought from rocket industries its an aeroflow 2000 cfm and I have about a 10mm clearance between the back of it and the bolt heads on the water pump. I also have an aftermarket aluminium radiator as well hope this helps.

[StephenSLR]

I end up stuck idling in suburban traffic and some of the intersections around my place can take 3 minutes or more to get through.  In that time, the temp gauge goes from around half (where it sits when I'm moving) to three quarters or more.  I know the factory gauge is crap, but it is showing a significant  temp increase while sitting in traffic and I'd like to keep the old girl cool.

Is your engine stock? I'm just wondering if there's another issue; a lot of guys are running the stock fan & shroud without problems.  You could have the wrong thermostat, worn impeller blades in your water pump, radiator cap with wrong pressure rating. There could be an issue with your cooling system.

If you don't have a radiator overflow reservoir; get one.

s

[GEOFF289]

Still think your first step should be to find out what is actually happening temperature wise.

[StephenSLR]

Still think your first step should be to find out what is actually happening temperature wise.

If you can, get one of those laser thermometers and take readings of temp at the thermostat; your gauge could be out.

s

[GEOFF289]

Well yeah that's an option but not so practical for seeing what's happening when he's out driving the car. I still think one of these http://enginewatchdog.com/tm4.html is a good investment. Shaunp on here put me on to them some time ago when I was concerned about what my dash gauge was suggesting and I am a complete convert now.

[barnett468]

.
any type of real temp gauge is easier to see exactly what the temp is than the factory gauge, however, if one does not want one they can simply check their engine with the infra red once it is up to operating temp and see where the gauge is . . they can then drive it and if it gets hotter than it should they can check it again so they will have a high limit and when the needle goes above that point they know to pull over.

one can also just let it idle and check it and after it warms up just turn it off and check kit again after around 2 minutes because the temp will likely go up then see where the gauge is.

another op is to remove the fan belt after it is warmed up then let id idle until the temp reaches 210 then look at the gauge so they know where that is . . they can also put a piece of very thin tape on the gauge at that position.
.