[5window]

I'm running a mild 350 in my Model A,open hood sides,new aluminum radiator.
The guy who had the car before me installed an 18" diameter fan, with the blade tips bent to make it a 17" (at least it looks like he bent them intentionally) and clear the lower radiator hose, which it does,barely. I've put on a new hose with stainless braid and a different clamp and I need more clearance. Summit Racing,and others, have some lightweight,high efficiency fan blades that are 15" and 16" in diameter. Can I use the 16" without expecting overheating (the car runs fine now)? What about the 15"?

Thanks.

[Classix_Lover]

I don't think there'd be any reason why a 16" belt driven fan couldn't cool your mild 350. Just be sure you encircle it with a proper shroud to promote good airflow and add a spacer if needed to get the fan as close to the radiator as possible and you should be all set.

[jpelli]

If you want to stay with electric fan , cooling component's make's a nice fan shroud, use a good fan like spal.

[5window]

Oops,sorry I wasn't clear. I am using a mechanical fan and I'd like to stay with that,if possible. It is a hotrod after all. Thanks.

[Deuce]

I like to use the ZIPs water pump riser ...
on a SBC ...

Raises the fan about 5 inches to clear the lower radiator hose and I can run a 18 inch fan ... with room to spare ... on my 32 ...
Also has a alternator mount cast into it ...

Parr Automotive and others sell them .
They are made in Pennsylvania.

[johnsongrass1]

GM 4 blade solid fan isn't very big, like 15" or so, and it pulls more air than anything else I've seen. Even the after market 6 blade fans don't come close. I can get a GM no for you if you wish.

Nearly every dirt tracker round here will use one whle running gas.

[home brew]

This story is to just give you an idea on how little fan you need if you are able to keep your ride moving and don't do much stopping at lights and no fancy air conditioning, etc. When I first built my 40 Ford with a 324 Olds in 1965 I used no fan. That's right no fan. I built the car and had it running in mid April. I was using a 36 Dodge rad and the placement of the rad hoses would not allow the stock Olds fan to clear.

In the next two weeks we drove the car from Regina, Saskatchewan to Vancouver, British Columbia and then to San Francisco and back. The car never overheated once in the whole trip until we got stuck in rush hour traffic some where in California. We went to the local junk yard and found an Olds fan and cut it down with a hack saw until it cleared the rad hoses. We ended up with fan blades about 6 inches long (12 inches in diameter). We put it on and checked for balance and drove away.

By the way the junk yard owner did not charge those "crazy Canadians" for the fan (I am eternally grateful for US/Canada friendship). That fan stayed on the car until I sold it. I did dress up the hacksaw cuts when I got home and painted it to look pretty. The car never did overheat ever again.

I never would do that again as I am sure I wouldn't get away with it and the fan would go through the rad. That rad did cost a whole two dollars though.

[johnsongrass1]

I put a electric fan in my SWB chevy three years ago and wired it with a soleniod and rocker switch on the dash. Looks nice. Although I havent used the fan for cooling since I was stuck in a traffic jam due to construction on I-70. It was about 90 that day in June of 2005. My truck never see's more than 230 with out a fan. Just good air flow I guess.

[5window]

Thanks for everyone's input. I have ended up with a 15" 6 blade. We'll see how it works. The local speed shop guy didn't recommend flexible blades-not enough cooling when they flatten out he said. So I've got a nice traditional Flex-o-lite, painted black which will look fine. I'll keep y'all posted on how it cools.

BTW-the Zips riser from Paar lists for $229. Nice idea,but I can buy a lot of fans for that.

[Deuce]

Originally Posted by 5window

BTW-the Zips riser from Paar lists for $229. Nice idea,but I can buy a lot of fans for that.

True ... but $229 will not buy you a new engine ... to replace the overheated one ...

[302 Z28]

Originally Posted by 5window

BTW-the Zips riser from Paar lists for $229. Nice idea,but I can buy a lot of fans for that.

Not a lot IMO when you consider it mounts the alt and AC compressor in a position that looks nice on a street rod. Most aftermarket brackets throw them out too far. Also it uses a standard six cylinder Chevy pump that you can get literally anywhere any time. Try and buy an electric fan when your on the road on a weekend.

Just my 2
Vince

[5window]

Also true. For the moment, after a long discussion with our local speed shop owner,I've gone with a fixed pitch 6 blade 15" fan that mounts where the original fan was,but clears all the obstacles. I'll try it out-always nice to know there are alterantives. Thanks.

BTW, turns out the old fan was way out of round,17" some places,17.5" in others across the diameters. Also the orginial builder used oversized washers as spacers. I expected things to run a lot more smooothly without all that slop up front.

[xntrik]

Originally Posted by 5window

Thanks for everyone's input. I have ended up with a 15" 6 blade. We'll see how it works. The local speed shop guy didn't recommend flexible blades-not enough cooling when they flatten out he said. So I've got a nice traditional Flex-o-lite, painted black which will look fine. I'll keep y'all posted on how it cools.

BTW-the Zips riser from Paar lists for $229. Nice idea,but I can buy a lot of fans for that.

The best flex fans in my opinion are the Imperial brand stainless ones with large square blades and lots of pitch. Derale used to market a good one but I think that brand is now defunct.

Plastic fans are worthless.

3/4 inch core clearance is good. If you don't have a full shroud, those little ring shrouds are worthless in my opinion.

That old wives tale about flattening out and not pulling air is baloney with a good fan.