electric fan vs shroud

[Fatolbaldguy]

I have now added an air conditioner to my 292 1965 c20. Which in turn required a beefyer alternator which I also put in. A six blade fan was put in. Now it runs hot. True the afternoon temps around here rarely dip below 105 so that does not help either. Hence the need for an air conditioner. Several folk have recommended taking off the engine mounted fan and putting in an electric fan. Also a shroud has been recommended.
A shroud specifically designed for a straight six chevy of my vintage has been elusive to say the least. My question is can I do both? Should I do both? What shroud should I buy? What fan system. Thanks

[tincan1966]

I personally would install an OEM V8 radiator(altho most list the 292 and V8 as same) with the correct shroud and install a clutch fan with 6 or 7 blades.

Even with an electric fan, some type of shroud needs to be in place to direct the most amount of air you can draw thru the radiator. Simple mounting a 14-16" fan to your radiator is leaving almost 1/2 of the radiator surface unused, unless driving at highway speeds since you now have a condensor in front of it.

You need to make sure that the maximum amount of air you can get thru the grill opening is coming thru the radiator- and that will include installing side baffles, if they are missing.

[markeb01]

Mechanical or electric fan really doesn’t make that much difference, it’s a matter of how much air either one can move through the radiator that counts. The shroud needs to reach every corner of the radiator core so the fan can pull cooling air through every square inch. And it needs to be designed deep enough to allow generous airflow through the radiator at highway speeds, when forward motion should assist in cooling the engine.

I have a Flex-a-Lite Black Magic electric fan on mine. It works adequately where I live, because it normally doesn’t get very hot around here. But the built in shroud only covers about 2/3’s of radiator core which would do very little good in your climate.

For years I’ve read you should never do away with the mechanical fan since it will always be there working after an electric fan burns out leaving you stranded. In truth, I’ve never seen or heard of an electric fan failing in the last 20 years. They are standard in many/most new cars now, and are as reliable as modern power windows.

I’d suggest finding a shroud that completely covers your radiator as the first priority, for either style fan. If that doesn’t fix the problem you may have to consider stepping up to a more efficient radiator.

[Rufton]

On my modded small block I installed a big block spec radiator. I have run different fan configurations and they have all worked fine. Started out w/ shrouded elec puller and backup elec pusher. Currently getting sufficient cooling w/ no shroud mechanical but I did leave elec pusher just in case. Over sized healthy radiator comes in handy about this time of year.

[vin63]

My buddy in Phoenix ran two electric puller fans in his A/C equipped C10 with a 406, but with a V8-sized radiator and full shroud. It was his daily driver and used it as his printing business delivery vehicle.

[TJ's Chevy]

My dad's 496 Big Block Chevy uses a Durmax Diesel radiator and dual electric fans. I would put a single 16 inch electric fan with a shroud. If you can find one that has a factory draw of 2000 cfm and ad a shroud you should be fine.

My buck and 1/2.

[Greg63]

I have both an electric fan and the factory fan shroud. The shoud covers the electric set-up which keeps it kinda looking stock.
The fan I used, strangely enough , is a Chrysler set up. I wrote the number down but can't find the paper I wrote it on.
The dimensions are perfect to fit inside the shroud and it covers the entire fin assembly. It has it's own shroud built as part of the design, and the fan motor can be plugged in to push or pull the air.

Greg.

[tincan1966]

I know it's a bad word, but have heard the fan assy from a Crown Vic police car are supposed to be good-flowing something like 2600+ CFM-specialy designed for alot of idle time and for hard driving conditions. I have one but have not used it.

[Rufton]

Originally Posted by tincan1966

I know it's a bad word, but have heard the fan assy from a Crown Vic police car are supposed to be good-flowing something like 2600+ CFM-specialy designed for alot of idle time and for hard driving conditions. I have one but have not used it.

I bet they do have a strong fan in those cruisers; the police run em pretty hard.

[63MOUSE]

i deal with the heat every day like you . last weekend i installed a fan set up in my truck. i had my 4 core radiator worked on and asked the radiator specialists what is the best electric fan to install and they said flex a lite black magic and to go to loper's to get one. loper's said they have a fan that they tested in their shop and the lower cfm maradyne blew the 3300 cfm black magic out of the water. i got the twin fan 2600 cfm and it covers all of the radiator except about 2 inches of the bottom. been putting it thru tests all week and so far its great. i hooked up each fan separately so i can test it with 1 fan or 2. but i agree with most, a good radiator and make sure the air flows thru and not around the radiator

[Greg63]

Here is what mine looks like (shrouded fan within a fan shroud);



Greg

[Fatolbaldguy]

arggh Greg/mouse! I just ordered a reproduction shroud for my Truck. I talked to an AC specialist mechanic and he said my aluminum aftermarket radiator that came in the truck is plenty big. Hopefully the 10-15% increase in cooling expected with adding a shroud will work. I have my doubts. I hate to think I threw another $115 at the problem for nothing!
63Mouse have you got a link maybe?

[Fatolbaldguy]

I cancelled the order for the shroud and talked to the owner of Lopers on the phone. (he answered the phone love that) and he said he has what I need so going to put Jugs of water in the back of old spooky and ride over tomorrow and drop off some money at Lopers..

[Fatolbaldguy]

It took alot longer than I expected but the electric fan is in and wired. The first fan I bought was too fat. Those 292s are long! So I trudged back to Loper's and got the twin fan unit which fit fine though It covers less real estate than the single did. Plus much more money But I can't complain I was ready to buy a radiator with a built in fan and they aint
cheap. How does it run? Well I only tested it yesterday but so far it still runs hotter than it used to before this saga began but it idles without over heating. It runs smoother without that windmill out front. Fo some reason the alternator seems to be charging like the battery is dead. That has me stumped I don't think I changed anything there. Thanks for all the help. Its nice to have the old girl back in the stable.

[tincan1966]

If the fan is running, you have about a 15-20 amp draw on the system, so the alt is going to kick in to keep up. If still running an external alt system, you may actually lose voltage at idle with the fan running. I'd suggest about a 63 amp or higher alternator with internal regulator, unless you've already done that conversion.

I am sure there are other fixes with external regs, but I am not familiar with those, I always replace with internal reg alts.

[vin63]

Electric fans can draw a lot of amps. A couple of questions: did they wire the fans with relays are they controllable individually so you can turn one off while driving at freeway speeds; and what is the output rating of your alternator?

[AzCountryman]

Little off topic.....I always worry about overheating here in Az. Blew my Explorer engine when I was younger from that. But heck it was a Ford. I installed autometer gauges in my 66 and it has a 327. The autometers dont have a red line for overheating so what is the "oh crap" temp for that engine?

[Rufton]

50/50 ethylene glycol w/ a 15 psi cap boils at approx 265F. Engine may self destruct quickly after significant percentage of coolant exceeds boiling point. Engine may self destruct at lower indicated temp. Temp sender may not accurately measure coolant temp, so max "oh crap" temp indication can vary. I like to make a note of normal operating temp indication so I'll know when things are getting heated. Oil temp and head temp are useful data points if overheating is suspected.

[Fatolbaldguy]

Its 117 degrees here today. I'm just going to leave it in the driveway for awhile.

[Rufton]

Back in the day, my grandfather said something about stringing bags of ice in front of radiator to fight overheating when they traveled from TN to AZ. I don't imagine that's popular nowadays

[Rich 5150 69]

They used these back in the 20`s to the 50`s hanging in front of the grille...

[Rufton]

Cool.

[lasher78]

new to fab work... if you want to fab a shroud how does it actually fasten to the radiator....mine does not have one and i dont see anything on the sides to fasten to
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[lasher78]

and does anybody have a link to that blaxk magic fan?
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['63GENIII]

I had a hard time keeping my truck cool before I had a shroud too. I went elect. and that didn't work. I tow approx. 8k of stuff to the lake during the summer mos. when it can get real warm. It took me a long time to take everyone's advice but I got a stock repro shroud, a 6 blade oem fan and clutch. Running a stock 4 core brass radiator with a 190 deg. t-stat. (I like the engine to run a little warmer). I've run this truck up around Sacramento area, sitting in traffic, 105+ deg. days and have NEVER had an issue. No pinging, dieseling ect. Before the shroud however, I couldn't even run to the corner store two blocks away without boiling over. I'm not saying it's for everyone, but the factory setup worked for me. When it starts getting warm, you really hear the fan kicking in. It can be a little annoying but way less annoying than wondering if you're gonna overheat on a hot day.