Thread: Fan to rad.

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Ok how close should i have my fan to the rad. Right now i am 4.5 inch away.
I will buy a fan shrod should it be 1 or 2 inchs away?
thanks Dave

My roadster is about 1 inch off the radiator ... and I use a 18 inch 7 blade fan ... and a Walker shroud ...

Not to rob this thread, but Deuce, can you tell me the setup you are running there? Looks like a Zips pump riser... does it run cool enough when it sits and idles for long periods of time? Does that shroud just screw to the little 1/4" flange on the back edge of the radiator? My deuce currently has an engine driven flex fan without any riser, and is only about 15" wide with no shroud. I don't want to tear the whole fromt of the car apart to change stuff, but i THINK i can take off the current fan and coax an electric fan in there without taking much apart but the upper hose and the flex fan itself... another thought was to buy a walker shroud like that and cut it to fit the engine fan where it is now (low)... I didn't think this was good, but a rodder friend of mine said he had a model A he did this to and it made a world of difference, even though most of the top portion of the rad was covered by the shroud... He said it forced the air down and through the shroud.... i also think i could likely "coax" one of these shrouds into place without taking the grille shell/rad/hood/headlight bar/etc. off the car, but not sure. Right now it seems to run fine when its moving, even at 25-35mph, but if it sits at idle for awhile the temp will start climbing.

I run the ZIPs on 32's ... and have for over 20 years. We have a ALL DEUCE club here in South Carolina and almost every 32 with a SBC in the club has a ZIP. Go to my project journal listed below and there are photos of the ZIP set up ... that I am installing on the 32 3W I am building.



... Mine runs real cool ... right on the thermostat ...
In traffic ... sitting still ... whatever ...

Deuce will verify, which I see he did while I typed this the first time. A similar unit would be a Snow White pump; http://www.snowwhiteltd.com/products.htm
Deuce, do you have a web site link for where to get the Zip's?

I don't know about the Zip's, but the Snow White places the fan mounting flange an inch closer to the engine which would give some "wiggle" room, not so much importance on a Deuce, but on later models where the rad slants back it helps.

this is one place to get them.

parr automotive

Those things are pretty pricey aren't they? Til its all said and done I'd guess you'd have 300+ in one, right? Anyone else running an engine driven fan on a deuce without a pump riser? I'm thinking I'm either trying a shroud or going with an electric... however, correct me if I'm wrong, but a shroud really isn't gonna make much difference in how hot a car runs at idle is it?

Originally Posted by 30coupe

this is one place to get them.
parr automotive

Thanks.

A shroud will make all the difference in the world at idle. Remember, when you're going down the road you're getting ram effect for air movement through the entire core. At a stop a shroud directs all of the fans effort through the entire core. No shroud, fan only does a small portion of the core, if anything (depending on installation).

Thanks Denny, you might check Parr's (30's suggestion), they were $20 less than So-Cal.

It's a shame the brackets are part of it. I like the alt down low to keep the top of the engine cleaner looking, and REAL hot rods don't have A/C! (Well, except for old fogies who can't take a little heat )

Thanks for the info on shrouds... if my fan is low in the rad (without a waterpump riser) and i put in a walker plastic shroud with the hold cut out low for the fan, leaving the upper portion covered by the shroud, will it help or hurt the amount of air pulled through the rad at idle? for 89.00 I would try it if there was any chance it would help.

This is a Snow White ... it belongs to a friend ... and it is on his Model A ...
The Snow White does not have the brackets ...

300 dollars is a fair amount of money ... but a LOT less than a cooked engine ... When you factor in the alternator bracket and the improved fan ... I believe them to be a bargain.

A 14 inch fan has the area circle of 153 inches ...
A 18 inch fan has the area circle of 254 inches ...

Thats a LARGE improvement ...

Originally Posted by joeybsyc

... if my fan is low in the rad (without a waterpump riser) and i put in a walker plastic shroud with the hold cut out low for the fan, leaving the upper portion covered by the shroud, will it help or hurt the amount of air pulled through the rad at idle? .

For any given arrangement, the fan is going to pull the amount of air it's gonna pull (don't you just love profundities?). So neither the fan nor shroud cares whether the hole is at the top or the bottom as far as amount of air flow. The fan shape/design will have more to do with that than location (in this type application). One plausible argument for having it in the upper half rather than lower is that the hottest air will have the shortest path of exit. That said, even with the fan down low pulling through a shroud is better than no shroud for the reasons stated in the above entries.

Now, the type of flex fan you've got there isn't known for being very effective. For a mechanical fan I prefer the type Deuce has in the picture above. If for no other reason, rarely if ever do you see an OEM application overheat. Which fan did they use? The funky little flex fan, or the modest pitched steel fan like Deuce's? (which also has some flex, just not as much).

I agree the flex fan isn't the most efficient fan design ever created, its there because they are 15" diameter, and thats all the clearance i have... I did find some stamped steel fans in 15" on flex-a-lite's website, and may look into getting one, along with a shroud. I'd like to try to make this work with a stock type fan setup, as I don't like the look of an electric fan. I'm not particularly crazy about the look of the risers either, although the one without the extra brackets cast all over it looks better than the Zips. In any case, I'd like to try to do whatever I decide to do without tearing the whole front end off of the car, in fact, I'm going to attept to finesse a shroud in there without even taking off the hood. I figure they've been building hotrods alot longer than they've been making electric fans and pump risers, so there's gotta be a way to make it work with a factory type fan setup. I'm hoping whats been said about shrouds is correct, and I can get it to idle a bit longer without the temp raising up too much. Makes sense that it should help. As it is now, the car is fine until it has to sit and idle for long periods of time, at which time it wil creep up until you start moving again, then the temp quickly drops back where it should be. Where I live it will be a very rare occurance that I'll ever be sitting still for long, so if i can improve it even a little bit, it will work for me. -JB

When my 32 had the 345 HP 350 aluminum head crate engine ... I did not have the shroud. My car ran right on the thermostat ... never getting above the thermostat ... ... BUT ... when I installed the 430 HP engine ... I had to install the shroud. The additional 80 plus Horsepower and the engine being brand new ... was just enough to make the car want to creep up in temperature when sitting for more than a minute or two. The shroud cured that ...

Thanks Deuce... that verifies that the shroud indeed makes a big difference. If you don't mind me asking, how tough was the walker shroud to install/cut? Is there any hole in it at all when you get it, or is it just a domed piece of black plastic? I plan to make a cardboard template to determine where the hole should be, then cut the hole out low to match my fan and attempt to slide the shroud in from the top without disassembling my 3 piece hood and hinge/latch system... I think I'll get an OEM styled fan like yours too while I'm spending money, although it will still be a smaller diameter. My engine is a low horse goodwrench crate with completely stock guts, rad is brand new, so it "shouldn't" be a tough engine to keep cool...