Will a clutch fan setup work on an open hood hot rod.

I see a lot of references to a fan shroud increasing cooling effectiveness, and it's only true with the perfect setup. If clearances are at a premium, then a proper fan shroud wont be a possibility either.
A fan shroud needs to have enough spacing away from the radiator to allow air to move easily through it, or it will actually decrease air flow, especially at cruising speed! I've gone through this with shrouds, and had my temperatures go from a little too hot, to way too hot when I put a shroud on, and couldn't get it more than 1" deep. The shroud I had built directed all the air through the fan nicely, but when cruising down the road at 45 mph or higher, it created restrictions because I didn't have the room I needed to get the shroud farther away, and air couldn't make the tight turn in the 1" spacing.
I pulled the shroud back off, and temps went back down to a level I could live with again.

 

My old Roadster radiator is a stock T upper tank (how crazy is that?) with a modern core attached. This was made by a local radiator shop for the original builder of the car. The engine was a hot 283 punched to 292 with 12.5:1 compression. Never had a heating problem, car has a factory steel 4-blade 57 Chevrolet fan.
My friend's track car uses a Mustang/Falcon 3-row radiator inside a track nose/half hood with an electric fan. He has had no problem with heat either.

 

Having only 13" is going to make it hard to find an off the shelf shroud, but I remember seeing this technique on the HAMB and a couple of other websites:

http://www.jalopyjournal.com/forum/showthread.php?t=380196&highlight=fibergl***+fan+shroud&showall=1

If it turns out that the radiator is really too small, you could add some additional cooling capacity by plumbing in a large heater core and hanging it under the car. Add a 12V computer fan or just hang it in the air stream.

Also, adding an oil cooler will pull heat out of the engine as well. Same deal, you can hide it under the car with a fan.

 

Fred, question.....is your trans plumbed to cool through the rad,or separate cooler?

If you run a separate cooler, it'll help the trans temp and engine temp also.

 

Looking at this pic depth is not an issue.



A custom aluminum shroud could look good and help at low speed getting air through the core. The vertical mismatch of the fan could be helped, but not too easily. You would want the fan moved back to the water pump to give room for the cone shape.



An electric setup would definitely be easier to configure.

The thing is, if the current performance is marginal, it wouldn't take a huge improvement to resolve it.

Maybe a deeper pitch flex, or a fixed pitch like the 4 blade.

Shrouding or electric are the best ways but he might get there with a fan change.

 

Shortening that spacer will help with the fan-to-hose clearance.

A shroud would help a lot, I think. If you look at how much effective radiator area the little 13" fan currently covers, it's less than a pie plate. A shroud would extend the fan's area to the whole radiator.

With a good shroud, you could possibly go smaller on the fan and get more airflow thru the rad.

 

You may not like the ugly looks of a electric fan, but a temp gauage at 220 looks pretty ugly also. A shrouded electric fan (Spaw)would be a good answer to your situation. Good luck

 

Had the same problem on my T because we live in Texas I had to run a shroud.To get the fan away from the top hose I raised the radiator up about an inch and I used a shroud that I got off Dearborn that I was going to use on my Falcon

 

Well, it took more than a couple of days to get caught up with (almost) finishing my shroud.

The first picture shows my situation is almost the same as Fred's, fan diameter limited by upper hose and filler neck and the upper tank limits the distance from the radiator.

I decided to make a ring shroud as I felt due to the small fan size a full shroud might restrict air flow at road speed, where it already cools fine.

I could not install a one piece shroud without removing the radiator, so I made it in two halves. Picked up a piece of .062 aluminum from Amble's then sheared and rolled it over at my kid's house. I trimmed it and bent an offset flange with one of those modified vise grip flangers. I had also rolled a strip of 14 gauge steel for the mounts, which I attached to the ring.

Once I had the ring made I fit and trimmed the top to fit around the tank. I then ***embled it and used some foam blocks to hold an even space around the fan. Once it was blocked in place I made up some pieces that attached to the side straps on the radiator and welded some pieces between them and the 14 gauge steel strip on the ring.

Took it apart, finish welded the mounts, blasted the parts, and sprayed them (with the wrong paint). At least the flat paint makes it easier to see in the picture.

The last picture shows my un-scientific test, before I added the shroud I could lay the store receipt on the face of the radiator and the airflow would barely keep it there. Afterwards it would be drawn toward the radiator from about eight inches away.

Hopefully, this increased airflow it will make a difference next time I get caught in traffic.

 

That's a great idea! I figured just a ring wouldn't be enough. Your setup is close to mine. I'll make one this weekend. On a side note, my temp gauge went out yesterday and I've got a new one. I'm waiting for another hot day to see if my overheating was gauge related.

 

Separate cooler for the transmission.

 

All it is, is a viscous hub. Under load the fan slows down and when it spins up the fan spins at the same rpm as engine. IMHO I doubt a hood would make any difference whatsoever.

 

Is there a reason you haven't switched to fixed blade fan?

 

Rich, that's a GREAT looking home-built shroud... very reminiscent of '58-'62 Chevy units (and maybe up to '64... I can't remember right now).

A shroud is unquestionably going to solve your problem. And you've got a LOT of room to move that fan back away from the radiator.

I've seen full shrouds on '40s and '50s cars... stamped, formed steel that transitions from the round fan to the rectangular radiator. You might be able to start with one of those and cut/splice and make one that looks like it's for an early car. I'm a huge fan of "no square corners" on fabrication projects... factory stamped pieces always have round corners, and look a lot cleaner.

If you are handy with fibergl***, you could glue up some blue or pink styrofoam insulation panels to the right thickness, then shape it with a rasp and make a mold.

If you get a new radiator, have the hose mount in the center, below the radiator cap. That'll get you a little more clearance too.

If you make a decent looking shroud, and you move the fan back from the radiator with a much shorter spacer, or no spacer at all, you can run a clutch (if you can find a clutch fan that is a small enough diameter). The benefit will be that the clutch effectively disengages at freeway RPM (due to the temps being lower, the viscous fluid "relaxes" and the fan freewheels, or nearly does). This means your engine isn't shoveling air with the fan, so your mileage will go up a bit.

Get rid of the flex fan... go with a factory steel unit. I'd rather run a HD 4-blade fan than a 6-blade flex fan.

-Brad

 

I read somewhere in here to take the thermostat out. Don't. Water needs to stay in the radiator long enough to cool down.

Secondly, if you need that extra push to get temps just a little lower, I swear by the 40 below stuff. I have been running it in my little 3 row radiator cooling that big 390 Caddy and it's great.

 

Fred, t buckets are unique, small rad equals heat, ran a T for a long time myself, a thicker rad has advantages and disadvantages, one being a longer time to heat up, but also a longer time to cool back down again. Lots of talk on here about fans, my perspective on that goes like this, even bladed fans create a vortex in the center of the fan reducing airflow, odd numbered fan blades chop up the vortex and pull more air. If you look at a stock application you'll see either a five blade or seven blade for stockers. Cheap alternative, try one first, see how that goes, second, a shroud does help, no matter how simple, if it were me, I'd also go to a 195 thermostat, keeps the water in the rad longer, honest, it works. A lower temp thermostat opens wide, water flows like there's no tomorrow and doesn't cool. I don't think you'll eliminate your cooling issue, but you can make it better, an eye on the guage is part of the T bucket experience. LeRoy.

 

Never considered it.

 

I did some measuring today and a 5" shroud like Rich B. made should do the trick. I'll get on it this weekend. I'm still rethinking the fan and have a few possibilities. It's obvious now, that it's going to be a combination of things and not a "one thing fix all".

I'll update as I go. I'm sure I'm not the only one dealing with this.

 

The temp sensor on a clutch fan is right in the front center, it gets it heat signal from the radiator core since its right next to it. Hood will have no effect on the clutch operation. You will find most clutch fans will be to big of a diameter, they were designed for lots of air at slow speeds. Junk that fan you have, I have a few of them I tried on my '37. I was buying them for a $1 or so at swap meets. I switched to a curved blade flex fan, also a swap meet buy, and eliminated my cooling issue's. Both fans were 17" diameter, one like you have, one a curved blade.

A bigger radiator will not cure a air flow problem, its your fan choice.

I have been there,

Joe

 

i had to go find this. thought others might want to see it.

http://www.jalopyjournal.com/forum/showthread.php?t=162030