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Electric vs mechanical fan?

13K views 96 replies 37 participants last post by  cv67 
#1 ·
Did a search and never found a real comparison. Building a cruise /show car with this 66 I have. I am looking at the cold case rad and debating on a clutch fan or twin electric. Not building a numbers matching car but more of a fun car enthusiast thing. What are the opinions on electric fans vs mechanical.


Thanks in advance.
Kevin
 
#2 ·
This is MY opinion: When I drive a muscle car, I want to hear the ENGINE, and NOT an electric fan motor when I'm at a traffic light on a summer day. If I wanted to hear an electric fan motor cyling on and off, I would just rip the big V8 engine out of the car and replace it with a blender motor, or one from a singer sewing machine.
 
#15 ·
I've long been a mechanical fan proponent and I agree 100% with not wanting to hear an electric fan cycling. But since having a new fan go through my hood and destroy basically everything in front of the engine to include both front and rear brake lines, my stance has changed. I'm installing electric fans from now on and if they don't keep up I'll find a way to make them work. I'm not risking my safety again.

But that doesn't mean you have to hear the fans engage. I'm installing a PWM controller with the electric fans that keeps the water at the set temp not by cycling on ad off but by varying the speed of the fan. This is easier on the fans and charging system and doesn't cause the noise of a fan that is just on or off. And I'll be able to lean over a running engine without worry of being sawed in half...
 
#5 ·
I agree on both opinions. I guess I am old and trying to look at this as a modern project. I have read lots on mechanical fans cracking, exploding. Now I realize when we buy off shore reproduction pulleys, brackets and fans they are usually (never) as good as originals. I have none of these parts because I am building a car I bought in boxes and it was a SB and I am doing a BBC. I like the thought of freeing up a few HP like the new cars. Thanks again for the input, appreciated

Kevin
 
#7 ·
If your 66 is a BBC with a short water pump you could look at electric fans. If it is a BBC with a long water pump you may need to look closely at the room you have. I have a 1965 with a BBC and a long water pump with very little room. The 1966 may have some more room up front. The problem is with the lack of room is it forces you to get electric fans that might not be up for the job. If you have a small block you have even more room. If you can fit the fans spend the money on a good set don't be fooled by the cheap ones saying they can pull a bazzilion cfm once you put a radiator in front of them they fall on their face. Amperage draw will tell you what you really have. For 2 fans look for at least 25-30 amps total draw or more. A thick radiator you may want to be close to 30 amps. I think I am like 27-28 amps on mine and they seem to work pretty good. AC will throw another dynamic into it. A pre-done kit might be the way to go as they have compartmentalized everything into a smaller space and already tested (ie custom shroud).
 
#9 ·
Thanks again,this is a short WP and I am looking at the cold case set up, rad,fans ,harness and switch. Alternator was upgraded to internal regulator and all new wiring harness front to back.

Great info and helpful
 
#10 ·
I also split the operation of my two e-fans. Each has its own power, ground, adjustable thermostat, temperature sensor and relay. This gives me redundancy and dependability with my fans.

They also have different temperature set points to keep the alternator from receiving a kick in the teeth with both fans kicking on at the same time.

And with an LS engine and 4L60E transmission that had to have the engine moved forward to clear the floor pan, I had to go with electric fans. There's not much room up front now for a big metal fan and shroud but two Cold Case E-fans keep things cool very nicely even with air conditioning.

Rick
 
#12 ·
I have a one owner with an LS-5 and a 4 speed. It also has Factory A/C. For the last FIFTY YEARS with the factory VO-1 cooling system. NO issues so far!
SO,,, When I built my / Driver//Cruiser (1970 Nomad Wgn.) I stuffed a 468 in it and a 700R4. I went back to the 1970 Chevrolet VO-1 Cooling system, WHY? Its easy, My LS-5 / M-22 car has been just fine for fifty years. YES,,, A lot of " NEW and IMPROVED " items on the table to work with.
My Silverado has TWO Electric fans, They are wonderful. My Silverados engine bay was designed and has the proper ductwork for the fans. NOTE: Both of my 70s ( 454 & 468 ) have the 1970 style VO-1 cooling system, With EVERY PART & PIECE in place! ( NO after market ANYTHING in my cooling system) ALL parts O.E.M.-Pulleys,,772-fan blade,,clutch,,811 pump,,shroud,, 4 row Cop/Brass,,ALL the rubber pieces.
I can park my 1970 468 driver in the sun on a hot day, Turn on the converted factory A/C to ( R-134) and let it sit and idle untill its out of fuel and does not get hot and boil over.
A mechanical or an electric system will KOOL your chevelle "" IF "" It is DESIGNED for your car.
When you get old like me you figure it out... " Good parts aint CHEAP, AND Cheap parts aint good." :surprise: Do what makes you happy!:smile2:
Bob
 
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#13 ·
Guys thanks for the interest and opinions to help me out. Good points and I am considering them all. I actually put the purchase off until I can decide exactly what I want.
Big thanks, great group on here.
 
#14 ·
Cheap fans do that, come right through the hood, and, other parts.

I am another fan of stock steel fans and A/C fan clutches, they work the best, and, looking at the setups frequently to make sure nothing is cracked, breaking.

Now, in my 1991 Toyota Camry, I support the factory mounted electric fans in it, as the engine is an emissions engine, set up to use its electric fans correctly...and, the engine sits sideways in the chassis, not good to try to mount the electric fans on one side of the car.
 
#17 ·
I have had both in the same car and I have to say the mechanical fan kept the car cooler. My car is a SB with a long water pump and the mid 90's serpentine drive up front. I used a junkyard GM fan clutch and replacement non flex fan with a BB shroud. Fan was about 1/3 of the way in the shroud. Radiator was a Chinese aluminum that fit well. Car ran at 180 all day long. New system is a Griffin with twin electric fans and the car runs at 180-200. Not a big deal but the mechanical is so much simpler and less expensive.
 
#18 ·
Billy, you may very well be right about fan noise. I have never used one and I'm only going off what I have read about the controller. And since the truck has such a cavernous engine bay and my inner fenders are out at the moment, I was standing inside the engine compartment checking advance literally moments before the fan made leave. I'm not a spiritual person, but I took this as a warning from whatever beyond there is. I will never stand in-line with a mechanical fan on an engine that's being revved again. It shook me pretty bad and that's not easy to do. I had scabs on my elbow from the alternator fan to prove that I'm not smart enough to heed subtle hints...
 
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#20 ·
That sure sounds scary Tom. I cannot blame you. Are you able to check the inside edge of the fan shroud for any signs that the tips of th fan blades were hitting the shroud before that explosion ever occured? Just curious if the motor mounts were allowing the engine to move enough for the fan blades to make contact with the shroud. Were you using a stock type rubber motor mount on the drivers side?
 
#60 ·
I've usd a mid 80's Z28 Hayden clutch for nearly 20 years; its seen 7000 often and even 8000 a few times. Original hood still intact. As Bob said, the clutch dont spin 1:1.

FWIW, the "near" oem setup keeps 600 ponies really cool. You dont need Efans, but if you really like wiring and added complexity, GO FOR IT!

PS I am NOT cooling ATF which may make the simple system work so good.
 
#22 ·
I run a solid engine mount on the drivers side, rubber on the passenger. I run a cheap APDI/PRO 8010322 Radiator - single row, 1 1/4 core (plastic tanks/aluminum core) and a 7 blade Flex-a-lite 1818 fan, no clutch and no shroud. It stays cool even in 100+ temps. While I've heard stories like Toms, I've run flex fans for over 40 years with no issues. I suppose there is always a chance of product failure in anything mechanical.
 
#25 ·
Use the stock components, including the fan, the fan spacer, the clutch, and the fan shroud. These cars were engineered NOT to overheat. The problems came when we ditched the stock clutch and fan, and added the "lightweight fiberglass and some aluminum fans all to "increase performance" Then the aftermarket fans got larger and guys pulled off the shrouds and basically ruined the stock system. If you keep your anti-freeze at recommended levels with the stock OEM components you likely won't have an issue. If you do go to an electric fan or fans, make certain you have a full shroud that covers the entire core. Personally I hate the sound of the fan. I have a mid-engined Corvair with a 350 where the back seat was, and installed the cooling system in the former trunk area. I'm running a Deadenbear electric water pump, no thermostat and an AFCO dual pass radiator with a fully shrouded fan. The pump and fan are controlled by a Davies-Craig digital controller that controls the fan speed in accordance with the coolant temperature. If the pump and normal airflow through the ducted air intake for the radiator can't maintain the predetermined temp the radiator fan runs, and can be programmed to run after the engine is shut down. Pretty trick system!
 
#27 ·
First I think there are two Chevelle camps to begin with the 1964-1967 and the 1968-1972 guys. First, the later year guys have a big advantage as their radiator is huge compared to us early model years. The radiator on the early years has a frontal area of 375-400 inches versus the later years 510-530 inches - big difference. In turn the later year guys can run a bigger fan to take advantage of the frontal area. I thought I read somewhere that the later year ones even had a return gas line so that you would not get the dreaded vapor lock -(may have been AC cars only). Also the later year guys have more room in the front for a larger fan and other stuff - like a real nice shroud that gradually moves air toward the fan. Finally they also designed the front to seal better with the radiator air coming in (on my 1965 the air coming in can go all over the place like over the core support which I fixed with one of those undercover engineering plates, my fiberglass hood now no long wiggles at highway speed). My guess in 1968-1970 the GM engineers figured out there was an issue and really built a good system which is why you get a lot of the stock stuff works even with a modified engine (assuming the right parts). Remember the old car (from 1950s/1960s) movies/shows they would show a car overheating. Now us guys with the early model years we have more of a challenge especially with AC. I think to myself sometimes gosh it would be nice to have 35% more frontal area and 25% bigger fan like the later year guys. I think the 1966-1967 models have a little more room in front then us 1964-1965 guys. However, you can get the early models with BBC to cool, it just takes a little work and a long water pump BBC does not help. Below I have some photos of my efan set up - look at all that room. When I had the mechanical fan it was such a Clown Show in the front to get the fan on/off when there was a shroud while trying to space the fan correctly so it did not hit my alternator or power steering no room for any clutch fan here. Now part of it is my own doing with the long water pump that would make things easier. At least we have options today.
 

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#29 ·
That's a good point you make. Going by the pics, it definitely looks like I have more room than you do on your car. The fan shroud for the 1970 pretty much sucks though, since it doesn't even come close to covering the entire width of the radiator.

But I haven't any doubt that the radiator on the 70 is bigger than your stock one is. Same goes for Corvettes. Even the BB 68's and 69's had some overheating issues. But by the early 70's they improved the radiator sizes. I had a 73 Vette with a modified engine for 6 years, and that engine styed at 185 degrees with a 180 thermostat even on 90 degree days when I was beating the snot out of it!!!

I thought people quit using flex o fans years ago..... I remember the fiberglass ones letting go all the time.. Just put the clutch fan in there adjust the bi-metal to your liking and be done with it..

I have a 69... So according to Lew I have it made...:thumbsup:
As far as I know, thise fiberglass blade fans really suck. they're also very loud. The stainless steel blade Flex-A-Lite fans are completely different.And they throw out a whole lot more air to cool the engine than any clutch fan I've ever had, and do so quietly
 
#28 ·
I thought people quit using flex o fans years ago..... I remember the fiberglass ones letting go all the time.. Just put the clutch fan in there adjust the bi-metal to your liking and be done with it..

I have a 69... So according to Lew I have it made...:thumbsup:
 
#30 ·
I am in the Efan camp

Do not have room for a Mechanical Fan that would not keep my BBC cool in City Traffic
since it would not be turning fast enough at low RPMs



I have SPAL Dual 11" Efans/Shroud on my little 16" Hi x 23.5" Core DF Rad with 2 Rows of 1.25" Tubes





and I only hear the Efans when they turn on while sitting in my Driveway
one Efan is turned on by the Temp sender set at 160*
the second Efan is turned on by a Toggle switch which is only turned ON in City Traffic when the Engine hits the 180* Temperature
and then OFF again when Temperature goes below 180*
never use the second Efan when on the Hwy

I run a Auto Trans and have a Small Trans Cooler located in front of, away from and down Low of my Rad

 
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#31 ·
I have a huge plate style trans cooler in front of my radiator too. I run the cooler lines to the cooler first, then through the radiator. I want the trans fluid above 120 degrees and that would never happen in cold weather if it didn't go through the radiator.

I've never checked to be sure but the plate cooler might even over-cool in hot weather so running the fluid through the radiator keeps the fluid at a consistent temperature in all conditions as long as the engine isn't overheating.
 
#35 ·
Have you run it the other way before to if any or how much difference in trans temp?
I have always thought the trans isn't going to get much if any heat from the radiator in cold temps simply because the coolant is going to be cooled a lot on the side of the trans cooler.
I may wrong, but I've never seen where a comparison was made.
FWIW My truck running down the road at -20 the trans is about 50- 55 deg.
 
#32 ·
Tom do not run my 67 in Cold Temps so do not run the Trans Cooler Lines thru the Rad

Put her to Bed the first of Nov and will not see her until April/May

The Temp Gauge for the Trany reads 160* to 165* 99.99% of the time
and that is with the New High Stall Converter
doing Back to Back Runs down the Track or sitting in City Traffic

Just a 10" x 15.5" x 3/4" Finned Trans Cooler https://www.jegs.com/i/TCI/890/823800/10002/-1
 
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