I have a aluminum radiator and an electric fan. It does not cool my 65 nova. The motor has some extras making around 435 HP. I also live in Florida. I know this makes it difficult to cool, but I am thinking the traditional fan and shroud combo would get my temp down. It runs around 195 to 200.

I know Big Dave has answered numerous questions before and I can see you have strong feelings about the elec. fan. My question is where can I get a fan shroud for my alum rad and at what price? Does it need to be made custom or what do I need to get a stock shroud to fit with a manual fan?

Thanks in advance for your help.

If the radiator is exactly the same as orgional dimension, i dont see why you couldnt put a shroud back on it. you can if it will fit put the electric fan on the front of the radiator and put the mechanical one back in.
If your radiator and water pump is in good shape, and mechanical fan should suffice on its own :thumbsup:

Paul my 72 does not have a shroud around the electric fans and there is no problems with temperature even with the AC on and air temps over 110 degrees. Running 195-200 degrees is not abnormal, my fans are set to turn out at 210 and off at 180. what is the thermostat temp in yours and at temp does the relay turn the fan on? Can you post a photo of your fan set up? A shroud will certainly help to make air pass over the entire core of the radiator.

http://i80.photobucket.com/albums/j199/64elcamino/zmeano/P2040005.jpg


I had a cooling system malfunction and the engine temp shot up over 280, broke the Autometer temp guage but did not hurt the engine.

here's a link for a mount & shroud set up by 66RICH... may not be exactly what you'd need but the plans are posted... you can modify them to suit your needs ;)

good luck ;)

http://home.earthlink.net/~2drcdan/id1.html

here's an image showing 66RICH's shroud on my '64

http://i7.photobucket.com/albums/y258/64Flyer/IMAG00042-7.jpg

I have a normally aspirated engine making nearly 800 horsepower that never gets over 195 degrees on the road (210 degrees in traffic with the A/C running in the Florida summer heat). I use a Griffin two core (each core is 1-1/4" wide) radiator with the stock plastic fan shroud and the BBC 7 blade thermal clutch drive. I have a Stewart Phase II water pump and use molded, not flex radiator hoses.

If your radiator is larger than the stock size for a Chevy II you might try one from another make or model of vehicle. Failing in finding one that fits. You can make one out of flat stock aluminum. It should have no less than 1/2 inch of clearance around the fan to accommodate engine flexing and cover the first 2/3rds of the fan blade. Without a shroud the air flies off the end of the blade and you loose a lot of effective area that the fan could be sweeping (this is why long distance commercial carriers have little vertical stabilizers on the ends of their wings to keep the air from sliding off the end for improved mileage). The aluminum can be pop rivited together and when you get a working design take it to a sheet metal shop to have it welded up into a one piece fabrication (unless you can TIG weld at home). They can also bead roll some seams to strengthen the flat areas.

Getting back to the overheating. When and where dose it overheat. In slow moving traffic, on the open road (interstate) or at idle at a light? It may not be a shroud problem if it overheats tooling down the interstate at 70 mph.


Big Dave

The alum rad I have is a lot larger than stock. My motor is just through the total break in stage, no oil on the outside of the spark plugs. I purchased just a seasoned block and all parts are new. It is a SBC bored .30, alum heads Edelbrock Perf RPM intake with a 1" spacer, an Edelbrock RPM cam and a Holley 650 DP. I can't find the paperwork to let you know the CFM of the elec fan. I am pretty sure the manual fan and shroud is the best for me. I am curious what is the difference in the reading of temp from the intake and from the block. ? I have it in the block.
To answer the overheating question, it just runs hot. Does not get any hotter than that, it just goes to 195-200 and stays, even in traffic. I put in a new 160 thermostat, just to make sure that was not my prob. The gears are a little tall for cruising, runs 2500 rpm at 50 mph.

All old school, no AC to run, just the small triangle windows- angled just right! =]

Thanks again for the input.
Paul

Here is a picture of my fan and radiator set up.

here is a better shot. sorry it did not send with the first one...

Just for giggles you should put a few hand tools in your car and head out onto the interstate. Pull off at a gas station by an on ramp and remove your existing fan and aluminum shroud (if you can I just noticed it might be holding on the radiator as well) and then hop back on the interstate to check to see if the temp drops as you get above 40 miles per hour. If so the hole in your current fan opening is too small and is restricting the air flow.

A mechanical fan came in either a 15" or an 18" diameter with the smaller fans having 4 or 5 blades and the bigger fans having 5 to 7 blades. The fans themselves were either fixed in place with a fixed pitch blade or fixed in place with flexible blades that flattened out at higher RPM. The high horse cars all had a viscous coupling (not fixed to the motor). This allows the engine to rev without there being a horsepower loss to fluid friction caused by the fan cavitating. The better of the two fluid (viscous) couplings is the thermally controlled version which only engages at low RPM and high temperature. The other version has a small but constant drag to turn the fan blades at low RPM.

The shrouds were all basically the same shape differing only in the length of the tunnel portion which depended upon the placement of the fan (you could not put too long a fan extension on the fan or you will burn up the water pump bearing and seal). (Check out a 1971 Monte Carlo fan shroud for a really long wind tunnel).

Radiators are not rocket science. You are trying to get the most surface area (metal) that you can get exposed to an air flow for heat transfer. The metal chosen is important for two reasons. It’s ability to transfer heat which is where Copper really shines as it is the best at heat transfer. And it’s ability to stay together under the pressure of expanding water being heated (material strength) which is where steel works very well. So why aren’t they made of steel? Well steel doesn’t conduct heat as well as copper or aluminum but it is cheap. Problem is it rusts. Aluminum is ideal for radiators as it is nearly four times stronger than copper and only slightly below Copper in transferring heat.

You can make a bigger tubed radiator out of Aluminum than you can out of Copper which is limited to a ½ inch tube diameter. Aluminum will easily support a one inch tube. Bigger is better in radiators. All of the radiators in passenger cars are undersized because of style reasons. For comparison most diesel trucks have 300 to 350 horse engines. They have a radiator sized to support that many horsepower. Compare your radiator to a semi’s and you will see your’s is lacking.

Big Dave

All of the radiators in passenger cars are undersized because of style reasons. For comparison most diesel trucks have 300 to 350 horse engines. They have a radiator sized to support that many horsepower. Compare your radiator to a semi’s and you will see your’s is lacking.

Big Dave

Diesel trucks make a lot more power when operating than the average automobile, therefore they need a larger cooling system. They have to operate reliably with an empty cab as well as pulling a set of fully loaded trailers under all conditions. The average automobile makes much less power and the range of conditions are much less varied. Crank your 400 hp motor up to 400 hp and see if the engine overheats before your butt puckers and you lift your foot.

Diesel trucks make a lot more power when operating than the average automobile, therefore they need a larger cooling system. They have to operate reliably with an empty cab as well as pulling a set of fully loaded trailers under all conditions. The average automobile makes much less power and the range of conditions are much less varied. Crank your 400 hp motor up to 400 hp and see if the engine overheats before your butt puckers and you lift your foot.

Actually 350 horse power is 350 horsepower whether it is made by a steam boiler an electric motor or a water wheel it is a measure of power than can be converted to BTUs mathematically. Most big semi's are under powered for their weight which is why cars think can move in and out of their way with ease (untill they judge the distance, or speed wrong). But they still make about the same 350 horse power as the SBC does, they just have to drag around a bit more weight.

Big Dave

Does it take more power to run a fully loaded 18-wheeler at 65 mph than a hopped-up 68 Nova with two guys in it at the same speed? If the Nova was making 350 hp how long would it be before they left the road?

Here is a picture of my fan and radiator set up.

that set up looks pretty good to me, what fan is being used ? is it thermostatically controlled ?

if so, is the controller adjustable to come on sooner ? that might be the issue you're having ;)

that set up looks almost like mine, i live in the high desert area of So-Cal and temp gets in the range of 110° all the time in the summer. my car runs 185° while cruising with a 185° thermostat. i have the 16217 Derale fan with the adjustable controller which is being used at the preset temp by the factory.

i hope i'm helping you,


JR (and your pics work fine) ;)

Thanks Dave. Not sure where the diesel thing is going with Team Tech Mike. Too much time on his hands. I was thinking the same thing about the restricted air flow. I also have the trans cooler on the front of the rad.

I will more than likely go back to the manual fan and shroud.

Paul

JR
Thanks for your help. I know most people are always trying to help. This is my first build from the ground up. So any advice is appreciated. Trail and error has been standard operating procedure!

Your fan looks bigger and probally a higher CFM. It will be more cost effictive to go the manual fan route for now. Unless I can come across a deal. I know people are hurting for $ these days.

Paul

take a look at the fan you have... look at the controller and see if it's a two speed unit, it's probably supposed to be set for the higher cfm setting. if it's not wired as such it's possible it's running at the lower setting which could also be the issue.

what fan/controller are you using ?

Thanks Dave. Not sure where the diesel thing is going with Team Tech Mike. Too much time on his hands. I was thinking the same thing about the restricted air flow. I also have the trans cooler on the front of the rad.

I will more than likely go back to the manual fan and shroud.

Paul

It takes less than 50 hp to run your car down the road at any legal speed, so the fact that it is 400+ at its peak power moment has little to do with anything. I was not the first to mention diesels, I just explained why they have larger radiators.
Your block temperature reading will be several degrees higher than the intake manifold reading, so I don't think 195°-200° is too high at all. The engine is actually more efficient at these temperatures.

hmmm... i didn't read/see where he posted the location of his sending unit. that might be it right there...

good call Mike ;)

Mike, please don't take offense. I was just trying to have a little fun back. Sorry...It is hard to type light humor. I DO appreciate all your help. Thank you. Paul

you can also always check your bottom radiator hose to make sure it is not collapsing, could have a weak spring inside ;)

Does it take more power to run a fully loaded 18-wheeler at 65 mph than a hopped-up 68 Nova with two guys in it at the same speed? If the Nova was making 350 hp how long would it be before they left the road?

You betcha. Most semi's are about as aerodynamic as a house. The semi is attempting to push aside a block of air 8 foot wide by 14 foot tall, plus over coming the friction of 18 tires flexing continuously under the load of the truck and cargo. The transmission has the same parasitic looses as a regular car only more of it. In general the diesel is running flat out most of the time were as the SBC is loafing 95% of the time and only straining on the drag strip or a high oval banked track.

Big Dave

My fan is a 16" 2100 cfm Maradyne. M162kf is the model.
I adjusted it to remain on and the same temp. 195-200.
What do you recommend? Is this a common problem with Novas or new motors? And again I appreciate it.

Paul

i have a Derale 16217, it's 17" 2400cfm unit

if you have it set at 195°-200° and that's where it stays... then you're just fine... right ? why not set it at a lower temp (say 185°) and see where it goes ? can you set it ? i'd try it as an experiment and see if that helps lower the temp to a more comfy setting for you ;)

Paul what temp are you trying to achieve? The 195-200 you run isn't to high for summer daytime running. What does it run on a cool evening? The 160 degree stat IMO is to low, I run either 180 or 195 depending on the car.

What brand of gauge are you using? Have you verified it is accurate with another one?

One more question, what is the pound rating on the cap? and have you had it tested?

I was running a 180 t-stat and just changed it out to see if it would help. Did not. My cap is a 16 psi.
Thanks

Paul what temp are you trying to achieve? The 195-200 you run isn't to high for summer daytime running. What does it run on a cool evening?

I ask again

The pressure cap is important as it will determine the boiling point of the coolant much more so than the anti-freeze will. Remember the motor is quite happy running at 280° F degrees as it is about that point that the oil starts to oxidize. You will need a 24 pound radiator cap and an aluminum radiator to accomplish this (Warning! you have to remove the brass heater core unless you want a lot of hot coolant inside your car). You can not get excited seeing the gauge approach 212° degrees thinking your coolant is going to boil, it won't so long as you have anti-freeze where a 50-50 anti-freeze raises the boiling point to 265° all by itself (the pressure cap raises the boiling point even higher).

Big Dave

the concentration of coolant in the water can affect the boiling point. A 50/50 mix raises the point to 223 degrees, 70/30 brings it up to 235 and the addition of 15 lbs of pressure to the system will raise it another 45 degrees. This is just an FYI cause the question at hand is how to help Paul get his coolant temperature where he feels comfortable.

I got the boiling point of 265° off of the back side of my 50/50 Prestone Anti-Freeze bottle: you're saying they're lying to me. :D

Hey at least I got up and went outside once today.

Big Dave

OK here is the latest. I pulled the fan and shroud off. The shroud does not, i repeat NOT make a nice seal around the fan. It is allowing the fan to pull from both sides. It has a 1/8th" gap on the left and right side.

2.) The relay switch does not have any part numbers on it. It looks exactly like a Maradyne product, which is who makes the fan, model MC162. The probe is stuffed into the radiator in the top drivers side. The control is located bottom passenger side. The control only has a power wire, not any kind of harness.
Dave, it is a beautiful day here in Florida. You don't need to go outside, I'll keep you posted.
Thanks again,
Paul

No seal around the outside of the shroud along the radiator, not along the fan, as I may have just said. SORRY...

Dave they were probaly figuring it in a system with a working pressure cap.

And I also learned that concentrated antifrezze will freeze. I had a bottle sitting outside one winter it it froze, not solid but slushy. Of course it was -32 that day in the sun.

Phillip,
To answer your question, it runs cooler as the temp gets cooler. The other night it was in the low 70's and the temp never got above 190ish.
Thanks.

If air temps were in the low 70's you should have running at about the stat temp. Mine drops to 180 on cool nights and the fan never kicks on.

How is your air/fuel ratio? If the motor is running lean it will also run hot.

Same line of reasoning if the motor is seriously over bored (more than 0.030") it runs hotter than a stock motor (there is less metal for the heat to pass through to get to the water). Advancing the ignition timing also raises it a degree or two as the temp must be held in the cylinder for a longer period of time (or if you look at it the other way it has more time to leak out). Higher compression creates more heat than stock, etc.

If you put the bulb of your gauge in a pot of boiling water and it reads at, or near 212° F then I wouldn't worry about it running at 200° degrees F.

Big Dave

I do not have a bung in the exhaust for testing that. I "tuned" it with a screw driver. If you are asking that type of thing, I have been slowly tuning it less rich as I go along. I only have a couple of hundred miles on the motor. It has always run this temp.