Cooling Fan Questions

[BFS57]

Hello;
It's been so hot I have decided to install my AC in my daily driven 57 chevy.
I have installed a aluminum rad. (3 cores), a (supposedly) 3000 CFM electric fan and still, the heat creeps up on me while sitting. I can hardley wait to see how bad it gets when I put the condenser in front of the rad.
I'm thinking of re-positioning the rad behind the core support before I install the AC stuff.
Now, while I have the cooling system all apart I think I want to change my motor driven fan to something else, but what? I plan on taking the electric fan off and mounting it on the front of the condenser.
Any suggestions about what fan I should change to on the engine?
I was thinking a fan with a clutch, possibly duel electrics with a shroud?? Just what will work "without a shadow of a doubt!!"

Bruce

[phat rat]

I wouldn't get rid of the motor driven fan. How many blades does the one you're using have?

[Fat Cat]

Before I started worrying about what else I could add to the system. I would look at what I have to start with. You could have a problem with the ignition that is masquerading as a overheating issue. Of you could be running the engine lean which also makes the engine run hotter. Steve Jacks wrote a real good article about this topic that exists in the tech section located here http://www.roddingroundtable.com/tech/articles/cooling1.php

[BFS57]

Hello;
Good reading. I have one of those "flex" fans on the engine. Thats enough info for me to look at a high flow water pump, fan with a thermo clutch along with moving the rad closer to the engine, now about 5" away!
The system actually works pretty well as long as you are driving but extended stopping runs the temps up and then the fuel begins to boil and the car idles like crap!
I will look at a high flow pump first, then a clutched fan from a Junk Yard.
I know that there is some sort of "rule about how far the rad needs to be from the engine fan.

Bruce

[WZ JUNK]

I solved a heating issue on a 57 Chevy once by having the owner reinstall the sheetmetal panel that fits under the hood and mates to the radiator core support when the hood is closed.  Does your car have this piece?  If not, it really needs it.  The owner had removed it as he thought it was unsightly.  This panel keeps the hot air that has been through the radiator from going back in front of the radiator and this is especially a problem when you are at slow speed or stopped.  I have solved several heating issues by adding a shroud that lets the fan pull air through all of the radiator and not just the area where the fan is located.   Additionally everything should be done to keep the hot air in the engine compartment from being recycled in front of the radiator.

Good luck.

John

[phat rat]

In my experience part of your problem could very well be the flex fan. It  sounds as though maybe you don't have a fan shroud. Also be sure all air into the grille area has to go through the radiator

[wayne petty]

exactly which flex fan...

there are several different versions.. and a few for reverse rotation.. i won't list those...


tapered blade version...

http://contentinfo.autozone.com/znetcs/product-info/en/US/cwa/983617/image/4/

Part Number:   983617
Weight:   3.95 lbs
Description:    Flex fan
Brand:    TorqFlo
Rotation:    Standard
Diameter:    18 in.
Number of Blades:    6

~~~~~~~~~~~~~~~~~~~~~~~~~

a full blade width six blade fan...

http://contentinfo.autozone.com/znetcs/product-info/en/US/cwa/983569/image/4/


Part Number:   983569
Weight:   5.4 lbs
Description:    Flex fan
Brand:    TorqFlo
Rotation:    Standard
Diameter:    19 in.
Number of Blades:    6


~~~~~~~~~~~~~~~~~~~~~~~


a full width blade...  7 bladed fan..

http://contentinfo.autozone.com/znetcs/product-info/en/US/cwa/983717/image/4/


Part Number:   983717
Weight:   6.04 lbs
Number Of Blades:    7
Color/Finish:    Silver
Diameter (In):    17
Installation Hardware Included:    No
Material:    Aluminum
Package Contents:    Fan Blade
Performance Item:    High Performance Part
Rotation:    Clockwise


there are 17" , 18" and 19" fans in both directions in multiple styles available...

[BFS57]

Hello;
I  have the first (tapered) style flex fan. Mine, I think has less than 6 blades. I'm thinking that a fan with wider blades will help. Also, I do have a shroud. Something I got at a junk yard from a Ford Van. I also have added a strip of ABS plastic around the top and down the sides (but not the bottom) to make an extension of sorts.
The biggest problem I have is when I am in traffic stoped not moving.
I really see how a high flow water pump would help with my problem as it would move more water and hopefully keep temps down.
I know the problem I have will only get worse after I install the condenser and compressor running an AC unit.

Bruce

[phat rat]

Is the fan about 50/50 into the shroud? I've read pros and cons as to moving the water through the radiator faster. The con was the water has less time to cool. How new is the radiator? If older have you had it flow checked? Is the radiator one for the street or circle track. The more fins per inch the more cooling it has.

[Bruce Dorsi]

Are you using stock pulleys or fancy aluminum underdrive pulleys?


As for fuel boiling, an insulated carb spacer may help.

[BFS57]

Hello;
Yes, the fan is just inside the shroud. I use a mix of 60/40 water and anti freeze, I read someplace that I should use all distilled water.
I am using the stock pulleys but I need to ad another on the balancer for the power steering pump.
Like I said earlier I wonder how moving the Radiator (last year) closer to the engine will effect this whole equation?

Bruce

[enjenjo]

If your shroud is working, there will be no effect moving the radiator. Are you using vacuum advance? Ported or manifold vacuum? Timing chain condition?

Modern fuel percolates easily.

[BFS57]

Hello;
I am running Vacuum advance, from the proper port off the carb. Don't know the condition of the timing chain but I recently had Ken's here in O town fix several oil leaks one of which was the timing cover, if the chain was toast Ken would have let me know immediately!
Like I have said this problem only rears it's ugly head while I am not moving. When I start to move, usually I see temps go down to around the 180 mark. So I'm thinking what I have "kind of works" just nor "good enough" especially after I put the AC compressor and condenser in!
Maybe I'm over "thinking this thing but I do want things to work so I'm not always thinking will I boil over or not?

Bruce

[wayne petty]

tapered blade fans save a lot of power...   but are almost worthless for traffic and HOT days...    they JUST don't move enough air at idle...

you also.. have the option...  of a power saving Fan clutch set up....

there are excellent design fans from gm cars...  and the big thermal fan clutches designed to work with a 192F thermostat and 70/30  coolant to water blend..     with a 180 stat the stat opens and starts the circulating before the fan clutch bimetallic spring changes enough to divert the silicone oil between the plates inside to transfer more torque to the fan...


i know i have posted this before.. but i hope that you are running a thermostat.. at least a 180F with the tapered blade flex fan..  

in traffic the thermostat will take control of the cooling system..  starting and stopping the circulation of coolant through the radiator so the fan can take heat out of it...       the coolant will continue to circulate inside the block and heads through the bypass hose or heater core to even out the internal engine temps... and to keep the coolant flowing past the closed thermostat until the coolant picks up enough heat to cycle it open..


installing a HIGH flow water pump can help... but with a thermostat...

why...  with a thermostat ... it increases the IN BLOCK coolant pressure...  as its pumping against the back of the thermostat..   this raises the boiling point of the coolant trapped and circulating inside the block...  keeping the HOT spots near the exhaust ports from boiling the coolant even with 13 pounds of pressure trapped by the cap...    i have not had a chance to measure the behind the thermostat pressures built up by the water pump at speed..   i plan on doing so soon..


sorry for the drawn out post...  i am just trying to help.. as automotive cooling system thermodynamics is not well understood...

[BFS57]

Hello;
Good suggestions. I am running a thermo but it is a 160. But lately, I notice the engine seems to come up to demp quicker than in the past.
Funny thing. I have a 32 with the almost same set up except it has a Walker Rad without ant motor driven fan, only the electric that comes with the walker and that car doesn't have any issues what so ever, run the AC all day! But these darn tri-5's seem to have inherent cooling problems, that why they make those "BE-Cool" systems costing thousands of dollars (mostly bling) to cool these cars. I even made a shroud that directs the air from behind the grill to the radiator and covers any excape path the air may have past the radiator. Used this with almost the same results I have now!?? You tell me! Do I need a magic wand??

Bruce