Guys,
I hate to ask this question, but, which direction does the bend in the fan blade tip point. To the engine or to the radiator. I've had heating problems when I sit and idle for 15 minutes or so. I think I may have had the fan on backwards. I had the bent tip pointing to the radiator.
Thanks, Jim

 

Hey Jim! I seem to remember the tips pointing toward the engine.

 

The rolled tips are to be towards the motor. They make the tips less noisy. Tip speed is where all the roar and pop noise comes from, like on a helicopter.

 

That's the way I thought it would go. But, after asking you guys I looked in my FE manual and saw a picture of other installations that had the tip pointed toward the radiator. Don't really understand the reasoning but I'll try it your way for awhile.
Thanks guys,
Jim

 

"Cupped" side of blades face in direction of rotation, some fan blades are oriented to rotate the opposite way,(serpentine,for example) ...do you have a shroud,have you changed something lately? Look for water spots that don't make sense...you could have a pin hole leak.

 

Seetwisted,
Do you really want to hear a sad story. Well, I have a fan shroud, a new 4 row Cool Craft Opti-Flow radiator and a 6 blade fan and I'm also running a 160 degree thermostat and new radiator cap. I used to have a 2 row radiator and a 3300 cfm Zirgo electric fan (pusher ) set at 200 degrees that cooled the engine well at idle. Worked great until the cheap *** Zirgo fan blade decided to come loose and it ate up my radiator. Now I'm afraid to use one on my 500 dollar radiator.
If I'm going 15 - 20 mph I don't have any trouble. My fan is sitting approximately 1 1/2 inches away from the radiator. I'm also using the small pully on the water pump. I've thought about the head gaskets but you'd think that would cause trouble all the time. I've double checked my heat guage and found it OK. The engine runs good ( 66 390 GT ) . Timeing at 6 degrees initial. Compression is 9.5 to 1.
IF YOU HAVE ANY SUGGESTIONS, I'M ALL EARS. THANKS JIM

 

Is the shroud a full shroud or one of those chrome,half thingys? If you have a full shroud, does the fan extend outside the shroud a little to draw air through? If the fan blades are completely inside the shroud they create too much turbulance to draw air through unless you are moving. You should be able to hold your hand in front of the radiator and feel the air being drawn through at an idle. Small pulley? Usually a smaller pulley is to keep the water pump from turning too fast at really high revs... I don't know if this affects idle cooling.

 

The rolled fan blade tips also act as winglets, like they put on airplanes today, they make the wing more effiecent. If they are rolled forward the won't do that as they need to be on the pressure side of the blade or wing.

 

Seetwisted,
The fan shroud was an aftermarket item that fits the radiator perfectly. It fully envelopes the radiator. BUT, the fan is mostly inside the fan shroud. I did read somewhere that the blades should be 1/2 in, 1/2 out of the opening to the fan shroud.
Also, to make the 4 row radiator work, I had to take the fan spacer completely off.
Do you think this is my problem ( fan being too close to engine )

 

Ford part # D3TZ-8146-C (1973-79) is the fan shroud to use in this application...it is shallow enough to allow good air flow...it will also work on 65-72 V8's with very minor trimming.

This shroud is on my '65 which has a four row radiator, and 6 bladed fan...and no fan clutch (viscous drive). All parts except radiator are Genuine Ford.

 

Bear 45/70,
The winglets at the tip of an airplane wing were designed to add lift and hide bad stall caractistics of the airfoil. It isn't intended to direct airflow. Thanks, Jim

 

NumberDummy,
I became a supporter this morning when I couldn't get on the search page. How long after you paid did you get the service and when do they ask you what size T-Shirt you need. Thanks for the part number.
Jim

 

The rule of thumb I've heard is that the fan should be half in half out of the shroud. I know there is a recomended distance for the fan to radiator, just don't remember the number. We recently had the use of different spacers come up in a thread, maybe someone else knows.

Isn't this a recent rebuild? I take it the water pump is new, change it anyway (defective impeler)? Is this a truck or the Fairlane (Radiator surface area)? What temp does the system stabilize at when cruising?

When you are stuck relying on the fan for airflow:

What temp is it stabilizing at under these conditions?
Have you tried keeping the RPMs up for cooling?

I think timing is a non-isssue to the point that you have some room for experimenting. I take it the 160 T-stat is to keep the temp down, that's gonna speed up engine wear. As soon as you get the cooling stabilized, bump to a higher temperature stat, 180 minimum. That's enough typing for now...

 

Hypoid,
The temperature stabalizes at 170 and stays there as long as your running down the road. I've double checked it with a different guage and found it correct. I realize that the 160 is too small but I thought by starting from 160 I'd have a little more time if I had to sit in traffic.
When you stop the temp inches up constantly. It takes about 10 minutes until it gets to about 220. If you let it sit longer than 15 minutes it'll start blowing water from the overflow tube. Last weekend I was adjusting the timing, using a vaccum guage to adjust the carb and in that amount of time it started coming out the overflow. Radiator cap is 13 lbs. The temp was 170 when I started tuning on it.
The electric fan I used to have (pusher)would bring the temp back down to normal temps and you could idle forever.
I double checked the water pump pully and found it to be 7 inches. I have a 6 inch pully that will give me 15 percent more fan rpm at idle. I'll install it today.
The fan was inside the shroud, so yesterday I removed it. I found I had more air ( just feeling with my hand) being blown back on the motor. I hope the air came from the other side of the radiator.
This is the 57 Fairlane. I've put over 12000 miles on it this year so making it reliable is a must. It's taken on all our trips so I'm afraid if I get caught is a traffic jam I'll overheat and have to sit on the side of the road until traffic clears.
I really believe this is an airflow problem but I'm just remember I'm the one that installed the rocker arm shafts backwards and had the oil pump drain the pan and fill the valve covers with oil. Thankfully that was before the engine was installed so no harm done.
Thanks for the reply
Jim