I am looking to put an electric fan on my open engine 46 International Rod.. As much as I hate to put one on this truck, I'm tired of having it overheat while in heavy traffic or moving real slow in parades, etc I'm running a 283 SBC. Any recommendations as to which brand. Some say they put out 3000 CFM of air, but then tell you elsewhere that the max CFM is really only 1000. I want a 16 inch fan and I've read that straight blades put out more air but are more noisy. Any help with this will be greatly appreciated..
Before you do anything make sure coolant is moving thru the radiator when idling. When the engine is cold, lower the coolant 1” in the radiator and start the engine with the cap off. Using the gauge or a heat gun make sure the thermostat is open and watch in the radiator if you see movement. If there is little to none, increase the rpm just slightly, 100 rpm is enough, if you see good flow across the top the water pump is turning too slow. A SBC doesn’t normally have this problem but I would still check. A fan shroud really helps along with a 5-6 blade fan. Summit and others sell a fan shroud kit for Circle Track that’s ez and looks good out of aluminum. Here one on a 40 Chevrolet with a stock sized radiator. 311” with 10-1 compression. 14” 4 blade fan.
A mechanical fan should work as well, if you have room and use a good shroud. I used this electric one on the latest swap we did. It moves a bunch of air and isn't too loud. https://www.summitracing.com/parts/PRO-67027 The other option would be to look for an OEM junkyard fan of that diameter. The OEM fans are pretty quiet and good at moving lots of air. The older Ford Taurus fans were a popular choice.
How about posting us some pictures of your setup so we can see what could be going on.. relative to air flow..
I’ve got Cooling Components fan/shroud units on both of my ‘32’s with 350 sbc’s and they keep them cool even in 100°+ Texas heat. They both have Walker Z line radiators.
An electric fan may be the solution to your problem, but it may be something simple like missing a shroud for the mechanical fan. Show us what you've got now first, that may help avoid adding things you may not need.
I took a fan from a mercury villager van and made my own shroud. Seems to work fine so far, and it's pretty quiet. 463" motor with a Meziere water pump.
Electric fans became a 'magic bullet' in our world for rather murky reasons. The wholesale adoption of them by the OEMs was one reason (monkey see, monkey do) but people forget that the OEMs had other fish to fry. The introduction of front-drive cars with transverse-mounted engines was one biggy, it simply wasn't possible to use an engine-driven fan in those cars. The other was CAFE requirements, searching for fuel economy under every rock. The ability to engage only 'under demand' eked out a few more tenths MPG, generally not one of our concerns. Add in the sometimes-spotty reliability, usually large additional electrical load and some snake-oil marketing and it becomes a 'buyer beware' situation IMO.
I try to avoid electric fans, If you really don't want to go the electric fan route why not invest in a zips riser and that will move the engine driven fan up on the radiator 5", centering a good fan like the one Summit sells has done the job for me on several cars and moves a lot of air. This riser uses a 6 cylinder water pump. This is the 6 blade steel fan I use and my car never runs hot, i can sit in bumper to bumper traffic and still runs cool. HRP
I built a 46 International with a 472 Cad engine. It didn't overheat. Had a bigger radiator made for it, and a 6 blade fan and shroud. Try a hi flow thermostat also. Smaller pulley on the water pump may also help.
How about a picture of the engine Bay of what you're working with? So we can see what room you have for stuff.
I have a 16" Flex-a-lite pusher on my 46 in combination with a mechanical fan. The electric helps keep temps from creeping up too much when in traffic. I'm using the Syclone S-blade series fan. The fan is reversible, rated at 2,500 CFM, and after 36,000 km's I haven't had a lick of trouble with it. I recommend it if that's what you're after.
When I ran into issues fitting a mechanical fan my eyes wandered over to the '86 Fiero sitting in the driveway ... got me the fan, the wiring and the relay. Worked great. Everyone has a Fiero somewhere on their property don't they? Come to think of it, this was a few years back.
I was against them for years. Finally put one in my newest 1960 F100 build. I'm sold. Thing cools on 100⁰ plus days like a modern car. I ran this one from Summit IX-30102049
Are you sure your harmonic balancer shows true top dead center? How much initial advance at idle? If it is only around 10 degrees initial, recurve the distributer to run around 15, it helps a lot Also make sure the idle mixture isn't too lean If that is all sorted out, and the rest of the cooling system is up to par, a 16" spal #30102049 curved blade fan is a monster, I have run it in several builds, never used a shroud. Bosch 70 amp relay with built in diode # 0 332 002 156 and a 100 amp alternater with upgraded alternator wiring. Fan draws 30 amps while running.
Nothing beats the correct clutch, fan and fan shroud. But your post doesnt show pics of what you have. There are "advertised" 3K CFM fans - https://www.summitracing.com/parts/flx-105390
Assuming the fan is mounted flush against the radiator, the ring around the fan acts as a basic but effective shroud by preventing air from coming in from the side, forcing all air moved by the fan to come through the part of the radiator that the fan covers. It's not quite as good as a full shroud pulling air through the entire radiator, but it's far better than a completely unshrouded fan sitting some distance from the radiator as that will mostly circulate the same hot air behind the radiator, pulling very little fresh cool air in through it.
I'd make sure it's not too lean and check timing. After that look at building a shroud. Even with a large electric fan stuck on a rad there is usually a good percentage of rad that still isn't being used effectively. A smallish fan used with a decent shroud will do a pretty good job of moving air through the entire rad core. Shrouds generally aren't the prettiest thing but either are electric fans, extra wiring and those gross plastic push through ties that most guys stick them to the rad with.
Maybe it's just me but I see a lot about fans but little about the size of thermostat. By changing to lower degree thermostat it will open at a lower temperature allowing water to pass through the rad and cool. An old hot rodder I knew used to run flatheads and due to the two water pumps he would drill out a few of the fins in the pump which would slow the water transfer through the rad allowing the water to not pass through so quickly and cool slower.
I've found very few electric fans put out anything close to their rated cfm. So when I'm in a situation where I have to use one I get the biggest cfm rating I can find and so far all have worked. When I stuffed the BBC V8 into my '63 Falcon gasser it immediately had issues with cooling, even with a large new aluminum radiator. Every time I stopped at idle the temp began to climb. I finally went to my local junkyard and pulled a two speed fan from a Taurus SHO and took it home. These fans are rated 4600 cfm in high speed, and over 3000 cfm in low speed! I wanted to test the fan before building a mounting bracket, and new shroud to install it, so I laid it on my garage floor and hooked the leads to a battery. In low speed it tried to lift off the garage floor, and when I switched to the high speed leads it did lift off and pulled the wires off the battery before I could stop it! That fan moved some serious air, and way more than I needed! I wired it to a relay for just low speed operation, and never had anymore cooling issues. I did have a switch I wired to bypass the stat and bring on high speed, just in case. But the only time I used the high speed was just to test it, or show a buddy how much air it moved.
I have no proof to support it, but I think most OEM fans you can find in any junkyard will be higher performance and quality than aftermarket universal fans. Car manufacturers care about how much current the fan uses in relation to air flow, how well it works, how much noise it makes and how long it lasts, aftermarket sellers care about how many fans they sell and if they live through the warranty period.
Delta t, I’m sure others can explain it better, something about heat transfer. If the coolant travels to fast it can’t absorb the heat efficiently. If it’s too slow the coolant will get too hot and over come the ability of the radiator to function properly……help me out guys I’m in over my head here….
Street applications, the water pump speed must at least match crankshaft RPM, to a maximum recommended 25% faster than crankshaft speed from Howard Stewart
In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys.
A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called “hot spots”, which can lead to failures.
The only electric fans that I will use on cars that I build are those from a company that is also an OEM to many major car makers, and those that make supercars, and hypercars. That company is Spal. https://www.spalusa.com/ I bench tested all of Spal fans we used when I worked at GM, and snuck in aftermarket ones. Each was within +/-2% of the published rating, which can easily be explained by environmental factors in the test facility. My Falcon has two Spal pushers out front (space constraints), in addition to the original fan. They run when the AC is on, when I am climbing the Sierra Nevada mountains, or both.
100% correct! I have even caught Automotive Engineers repeating the common myth of "dwell time". I ran a controlled experiment when I was at GM, and once-and-for-all proved this to be a fallacy. There is an upward limit in every system, but that is not due to coolant velocity, but the potential for cavitation in the water pump.
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