Technical Best way to Change Fan on 239 Flathead ?

Our 53 Victoria only has a 3 blade fan and its riveted to the pulley ***embly. I'm going to install another with more blades. Should I just find another entire ***embly to bolt on or can I grind the rivets off the current one and bolt another fan onto the current ***embly ?

Thanks-

 

Swap them would be the easiest.

 

I ground the rivets off, enlarged the holes a smidge, and installed a 6 bladed FAL flex fan with their 1" spacer and grade 5 hardware. I'll take a picture tonight. Works great.

 

Just swap it out with a larger multi blade.

 

Here's my experience : Last summer, I had to replace the fan bearing in my '51 coupe. In the interim, I bought a 6 blade flex fan that bolted onto a spare carrier I had laying around. Over the next week, I noticed the temperature would climb more than usual during periods of long idling. When I reinstalled the original fan ***embly, everything went back to normal. That a three blade fan would cool better than a six blade seems odd to me. I think it is because the stock setup is a system that is designed to operate at high efficiency. Just throwing a 6 blade fan into the mix compromises the original design. If you have cooling problems and adding a fancy aluminum flex fan doesn't fix them, don't be surprised. A production Ford fan with more blades is another thing altogether.

 

Why do you think they call them "flex fans"? The blades flex to flat when at high RPM. They pull less air.

Henry Ford and his engineers were not dummies. They probably tested a couple dozen different fan designs, and used the one that worked the best. I doubt Summit Racing did that.

 

Are you just replacing the fan because you think it doesn't have enough blades, or is it because you are having cooling issues?

If it ain't broke don't fix it 'till it is.

If it is broke, its probably something other than the fan that has been working fine for 60+ years.

 

If you want a little more flow, but keeping a stock look and function, find a Mercury 4 blade fan. And they bolt onto the hub.

 

All I can say is my fan works well. Anyone who needs a fan at high speeds, when a flex fan is "flat" is in serious trouble. They should see a mechanic as soon as possible. As far as the stock 3 blade fan being designed well, SURE, when the motors weren 60 years old with numerous miles and potential rebuilds on them. A proper(reputable company) 6 blade fan will flow better at idle than the factory. BUT, you need to read the specs and make sure it's close enough to the radiator and a shroud is recommended.

 

Just a sidenote: At highway speeds there is no fan that will help cool your engine. The fan becomes the problem, not the solution, because no fan can pump as much air as natural flows at speed. The fan becomes an obstacle to air flow and the more blades it has, the worse the obstacle becomes. I'll go further to say that a flex fan is even worse because as the blades flatten they don't push air at all and just sit there as a spinning dam behind your radiator.

 

I don't think I got the point. If you have an over heating problem it is very unlikely that adding more blades to the hub will fix anything. If you don't like the three blade "look" that's one thing; if you are trying to fix a cooling problem it "ain't" happening!

 

Thanks for the replies. It's not overheating. I just figured a 4 blade will pull more air and be better since the majority of driving the car sees is 30-40mph around town.

 

the '49 fan had four blades. when the "50 ways better" 1950 model premiered, one of the improvements was the 3-blade fan, which was quieter and moved more air!