hey guys, after i inadvetantly bent my fan blade enough to grace the radiator--not enough to damage just enough to hear the noise and scare me. i started wondering how close is to close? as far as i know ive got a stock set up on my 53 ford customline but it looks preety dang close to me. sorry no pix but its gota be about between a 1/4 anda 1/2 inch at most tim
actualy now that i think about it maybe its not stock. its a 5 blade and there was a 3 blade in the trunk. previous ownder said soemthing about running one in the winter and one in the summer "back in the day" never thought to see if one was any deeper then the other tim
i was paging through my 55 chev shop manuel the other day & it said 3/4 of an inch or was that 5/8 - anyway i know its not a 55 chev but thats what it said. ---- closer than i thought.
My '56 Dodge's fan is about 3/4 inch away...I'd say if you can stick your finger between each blade and the core...it's ok. I'd run the 5 blade...if the thermostat does it's job correctly you shouldn't have to worry about over cooling. The 3 blade was probably just made to be lighter and reduce stress on the water pump...just a guess though.
I was at this stop light with some kid revvin up his rice burning heaping pile of cup holders, I'm in my 53 so when the light turns green I left em good. I held 2nd pretty long and never had that old motor wrapped up so tight before, this was before the rebuild of course. All of the sudden I hear a huge bang and some loud knocking sounds. I pull it over and find that it was the fan, the fan had flexed so much that it grabbed the harmonic balancer and went inside the groove of it, bent the holy hell out of one of the blades and just chopped up my belt, hoses and so on. It was then I decided 12v electric fans are the way to go. Did you know you gain 17HP when switching to an electric fan? If you think that's me talking outta my ass, look it up. Mechanical fans rob a lot of power. Think about it. But if you're going to use a mechanical fan, allow for the flexing, like Tim says or Stromberg, about a finger's width or 3/4". Some guys don't want to run electric fans because of the look, and yeah on some cars they are ugly as hell but don't get one in front of your radiator, get a pull type and replace your mechanical all together, no one will see it.
Maybe it's just an optical illusion, but the fan hub pulley in your picture seems to be too far forward (should be in line with the water pump pulley). Like I said might be just an optical illusiion.
Did you see how many amps an electric fan pulls ? That puts more load on the alternator of if you are like me , generator, that drags the motor down.
You're right, I'm assuming a 12V alternator setup which I know works because the slight drag created by the amperage drain of the electric fan is by far way less drag than a mechanical fan hard bolted to the rotational mass. Mechanical fans do their worst at higher RPM. For a generator setup, either get an alternator that looks like a generator, jegs has em, or a flex fan that flattens out at higher RPMS to create far less drag. Or.. fuck it, it's hardly a noticable difference anyway right? I mean what is 17HP on an 1800 pound car?
man 3/4" is as far as you would want to go, I'd say an inch is your best bet. Not only do you need to worry about fan flex at higher rpm but also motor movement. Many of the rubber mounted motors can move a lot if you hit the binders real hard. The electric thermo fan is the best way to go if you can put up with the look or hide it. To cool effectively you need to maintain air volume through the radiator core. Electric fans do this VERY well. The mechanical fan is quite average due to the flex/movement issue. The closer the fan is the better it will work, cant do it with the mech fan. To improve the effect of a mech fan you should make a tight fitting shroud so that all the air that the fan draws must come through the radiator. Doc.
3/4 of an inch has been the rule of thumb in my experience. Careful if you straighten the blade. If it seems weak at all get a replacement. Get a good used one. Using an electric fan on a basically stock car like yours just sounds lazy to me. It's easy to do but Fords like yours have been cooling just fine for over 50 years. Sorry, I hate electric fans.
I never had a problem with cooling using a mechanical fan, every car I've ever owned from big block to 4 banger could idle sitting still on a 110 degree day baking in the sun till it ran outta gas. If the timing is right, and it's not running rich as hell, all the fluids are good, it'll keep it cool. My problem is the flexing and drag, and an electric fan: Elimates flexing as a problem Cools even more Reduces drag which gains power The extra cooling is a bonus. It's really just whatever you prefer. For my 235, I'm obsessed with hopping it up. I could get a hell of a lot of power out of every big block I've ever owned, that was easy shit. But getting one of these old inlines or flatheads running good enough to keep up with cars with twice as big of motors is really awesome. So yeah, it's preference. I think if cooling is your problem and you don't wanna go electric, find out why in the hell it's trying to overheat. Electric fans have also inspired a few other bitchen designs. Obviously I wasn't the first to have this idea. The DeathsDoorStep rod has the radiator mounted in the rear with an electric fan so in the front, all you see is motor, nothing to obstruct your view of that darn purdy gitup.
mine is 3/4 of an inch,no shroud and it only runs a little warm(not hot) in the heat of the day(its been in the low 90's here).stop and go traffic it warms up pretty good but as long as I'm roll'n it does fine,it looks to me like the pully's dont line up either in the pix
yeah now that you mention it the pulleys do look off in taht pic. though i think it may be just that pic ill check when i get home this weekend. im not even sure the belt was all the way tight in that pic tim
HP is a function of torque, all the ads that say "+15 HP!" make me laugh. Removing the fan doesn't increase power, it reduces parasitic drag. Light flywheels don't increase power either. Electric fans with a large battery won't make a noticeable difference in power lost through the generator on a 80 horse engine. When you decide to go racing and every little bit matters, it might.
Pull types cool better because you loose 20% air flow with a push type since the fan assembly blocks air flow.
The distance from the back of the fan pulley to the generator belt should be appox. 1/4". If it's more than that, there may be some issues with the pressed in shaft or the fan bearing assy.
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