HI - 56 F100
351c
c4
jag rear

Huge radiator with an electric fan.

No shroud

The truck runs at 165 degrees on the highway - or really just moving. Gets enough air through the rad to keep it plenty cool.
My issue is in stop & go traffic - I'm about to pull a float in a parade so I'm looking to do something soon.

Temp climbs up - worst I've seen it was 200 - which isn't hot - modern cars run 195 thermo's.

But - I've not been stuck in traffic for more than a few minutes. I'm afraid that an hour in a crowded street pulling a trailer will be too much & I'll blow a hose or something in front of thousands of people.

I want to put in a real fan & a shroud. BUT as with many hot rods - clearance is a real bitch.

Is there somewhere I can get a short shaft water pump? If so, how much clearance will that give me?

Here is a pic.

 

Let me add - that I used to have a 57 *****'s wagon - it had a similar cooling issue & I tossed on a fan.

It worked great!

Right until I hit a bump & everything flexed enough for the fan to catch the edge of the radiator & bore its way right through the center.

I don't want to have the fan too close - not sure how close is too close - can you guys help?

 

You need a shroud.... I recently changed my water pump and didnt reinstall the shroud because the previous owner had used bailing wire to attach it. The next 3 days were no fun, lol. The shroud makes the fan pull air through the radiator...

 

The benefit with a shroud is that it makes it possible for the fan to pull air thru the whole radiator, Not only the area covered by the fan.

One solution, when you have limited clearence between waterpump and electric fan is to replace the electric fan with two smaller and make a thinner shroud out of sheetmetal with just 1" or 2" between shroud and radiator core.

 

What the replies above said. You need a shroud to get air flowing through the entire radiator. Offset the fan if you have clearance problems with the water pump hub. You may have to modify or build a shroud.

 

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My shroud, mid 60 GMC pickup. Modify it some to fit the Dodge rad.

 

Thanks everyone - I'm aware I need the shroud - just need more space to fit the fan.

I'll look into offsetting - or even the Lincoln VIII fan - looks like it can move some air.

Where did you get that shroud? what did it come off of? That's the set up I am looking for - though maybe a square one that covers more of the fins.

 

A couple pictures of how I modified the six cylinder shroud on my F4. A sheet of aluminum bolted to the original shroud was not difficult to fabricate. I've not had the rig at road speeds yet but it cools 350 CID well at idle and driving around slow. It is a sixteen inch 2400 CFPM fan. BTW, the belt pulleys do line up.

 

Personal opinion, I think the electric fan you have is just too small, compare it to Ray's fan. The right electric fan will be better in parade situations than a mechanical, it can produce full flow at zero speed. It looks like you have plenty of room for either option.

 

Thanks team! I just ordered the Lincoln VIII fan. Interesting article about it. They say its as well known as the ford 9" rear end.

good ol' ebay - I should be good to go in a couple weeks. Just in time for the parade!

 

I personally would ditch the electric fan and fit a eng driven fan with a shroud .
Plenty of room there to fit one and they are more reliable .

 

You definitely don't have enough air flow through the radiator at low speeds. The way it is set up right now you are only pulling air over part of some of the cooling tubes at low speeds. If you add a shroud you will pull air over all of the tubes all of the time. At highway speeds you are getting airflow over all the tubes all the time. The more tubes that have air flowing over them the cooler it will run. A shroud to direct the airflow through the radiator will definitely help. Do you know the CFM rating of the fan you have now? You may need one that will move more air, but I would add a shroud first, then change the fan if needed.

 

Thanks. Already ordered the new lincoln fan. It comes with the integrated shroud. Has 2 speeds & is almost the size of my rad.

Now i'm looking at how to wire it so nothing melts

 

sounds like a good setup. Definitely wire it through a relay, maybe an adjustable thermostatic controller, or you can get a pre-set controller...

I knew about the Lincoln fan, might need to consider one for my Mustang, it has the same problems that you're having, and for the same reasons. I don't drive it much when it's hot (no AC) so it hasn't really been a problem.

 

I need to trace the current fan circuit. It was added after the new electrical harness. Its always on with the ignition. Must be a relay in there somewhere. Large gauge wire too. It might work for the low side.
I have an ols solinoid i could use for the high.