Thread: Another radiator question

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It seems this subject has been hashed & re-hashed but I need an (some) opinions on my situation. I have a '39 Ford two door sedan, standard model. I made a core support and installed a brass Mustang radiator because of the space limitations. In the Illinois heat(95-100 degrees) it creeps up to 210 in traffic but I know it could run cooler.
As I see it, my options are:
1) replace my 14" Spal fan with a 16" Spal fan(pusher)
2) buy a 2 row(one inch tubes)aluminum radiator
3) move the radiator forward 3/4" and run a puller fan, deleting the mechanical
4) get a taller radiator that would still fit the car
5) get a Cooling Components assembly with the matching relays
If any of these, or a combination of these make sense please advice me. I'll be going to the Frog Follies in a week and I'll be shopping. Other than that, it's eBay. Thanks in advance, Rod

A pusher fan blocks an area of the radiator equivical to a solid circle the size of the fan when it is just windmilling (not under power) and is very ineffective at anything less than full speed

Like a windmilling airplane prop----------

Do whatever is necessary to get the fan behind the radiator --------hint-electric fans-use the highest amperage one that will fit

raj4851, from your options listed, and in particular your #2 and #3 it sounds like you are running a standard belt driven mechanical fan pulling, and then you've installed a 14" SPAL fan out front as a pusher. If that's the case IMO you've either got a radiator that's not flowing coolant properly, i.e. it's got some internal plugging; you don't have a good shroud for the mechanical fan; or you've got a water pump problem. A radiator of adequate surface area and tube count will cool just fine with the properly shrouded mechanical fan running a clutch to let it freewheel when it's not needed and a thermostat to control the flow. Pusher fans are a last resort, only used when there's simply no other answer, and they are NEVER needed to supplement air flow - they block flow running down the highway and are a negative value, again IMO.

If you're forced to look at an electric fan it's critical that you look at the fan SCFM with restriction. Free air flow means nothing. IMO SPAL makes just about the best electric fans out there, and one of their fans sized to fit coupled with their programmable controller is a good choice, but only if you can't run a belt driven mechanical fan because of space.

Give us a description of exactly what you're running now, including pictures of the shroud & fan on the back side if you can, or a detailed description of how the fan fits into the shroud, clearances, etc, etc, and we can see what makes sense. What degree thermostat are you running?

Here's a tutorial that I wrote originally and that has been improved by another dozen hot rodders. Please read through it and take an assessment of your own installation....
http://www.crankshaftcoalition.com/w...cooling_system

.

Pusher fans generally suck. Have you tried running it with the pusher removed?

rspears, I've never scfm listed for any fan. Maybe I need to do more research. I have a 3" shroud and attached part of another shroud I already had to make it a full round shroud. The fan, a flex type fan, is about 1/2" out of the shroud at the back. It made no difference. The radiator is "new", 1100 miles or so, so I'm sure it's not plugged. The water movement in the radiator seems to be good. I've never heard of a good way to check the flow of a water pump without taking it off and inspecting it.

techinspector1, neat tech article, especially interesting about the water pump impeller. I'm wondering about mine.

Henry Rifle, I've thought about taking the pusher off & checking the heating problem.
Thanks to all, Rod

Rod, when my 40 was together it had a Griffin aluminum radiator with a 377 stroker sbc. It had a flex fan bolted to the water pump pulley with no shroud. It would get 210 and higher trying to get into a show on a hot day. I removed the flex fan and installed a 12" puller electric fan I had and it worked great. It never got over 190* after that.

Hi 40FordDeluxe, and thanks for the comment. I think this is what I need to do. Do you also run a shroud with the puller and do you have a recommendation for a brand? Thanks again, Rod

I did not have a shroud on mine. When it goes back together it will have. I'm going to go with a spal unit when I get to the fan.

Hi, 40FordDeluxe. That's a great help. That's the direction I'll go. Thanks very much, Rod

The "shroud" for a puller can simply be a sheet of flat aluminum with the sides folded down to stand off from the radiator a minimum 1/2", folded again on the sides to form a flat flange to bolt to the radiator (flat Z on the sides) and a large hole on the surface for the fan. Run the largest SPAL that fits your radiator width. A SPAL programmable controller is a plus, fed by a SPAL sender in the intake water jacket port.

The car in my avatar had overheating problems since it was first built about 15 years ago. I tried everything that I could (shrouds, mech fans, electric fans, high volume pumps, standard pumps) and nothing worked.

The car came with a massive 5 row custom built copper radiator when I bought it as an unfinished project.

Last year I got completely fed up with it and redid the entire cooling system. I used a Griffin 2 row aluminum rad (one of their Rat Rod series)and a Cooling Components puller fan. No over heating now. The CC fan requires either 2 40 amp relays or a single 70 amp relay. It moves a lot of air. I think the free air rating was 2700 cfm, but as said, that means nothing.

We did the Hot Rod Power Tour this year and that required lots (LOTS) of idling in stop and go traffic. The system did great. No overheating.

I actually think the original rad was the problem. I couldn't make myself believe that the giant rad wouldn't cool, but apparently it wouldn't.

BTW - If you do run an electric fan, make sure your alternator is up to the task. My old style (CS 12?) GM unit is supposed to be a 97 amp unit, but it barely handles the CC fan. Even though it charges, I'm beginning to think it's not putting out what it's rated for.

Mike

The biggest differences between copper/brass and aluminum rads are the tube widths inside. Most aluminum rads start at 2 rows of 1 inch tube width and go up in tube width from there. That width is more flow which is what helps keep temps in check. Width also equates to a wider tube surrounded by fins which in turn has more surface area for air to flow over and remove heat.
Copper rads are usually rows of tubes that are 3/8" wide which means 2 rows of copper are actually less in flow capability than 1 row of aluminum 1 inch tube.
Now I have nothing against copper/brass rads as they have been around forever, but alot of times guys will use a rad they salvaged from another car cause it fits. One must remember for example....a rad from a 69 Camaro w/a 327 /250 HP motor will not cool a 572/800HP blown motor.