My 57 Olds is a J-2 with big valves ,. a 270 degree cam and 6 speed. I drove from Missouri to Texas last year and found that I still have heat issues. Factory AC cars had a 6 blade fan and a shroud , both of which I have not sourced in 5 years of looking. So I went to a 76 Olds 6 blade on a Hayden 2947 clutch. The radiator is a 58 that has a 26 W x 20 H 3 core. I added Vintage Air but haven't been able to use it. On the hiway the engine runs maybe too cool 160. But in town or the ubiquitous work zones 190 comes quick . Alcohol gas boils and a relaxing trip goes haywire. Kit Master offers adjustable clutches for 6 bolt fans and big trucks. I can't figure a good way to re-time my clutch fan to say 150. It now engages at 175 air temp which I think is too high. I understand that rotating the groove counter clockwise would do it but I do not know how to weld on an oil filled clutch. I would like to go with an electric puller but I only have 3 1/2 inches and a shroud of 1/2 inch is a door instead of a funnel to me. A 16 inch puller and PWM control with or without a shroud? I have a buddy who solved this problem on his 57 with the stock fan and 2 pushers but I just don't want those plastic gremlins greeting me when I open the hood. Please share your experience and advice.
Get rid of the clutch. Build a decent shroud. I was thinking that my 354 Hemi was getting too hot last weekend at over 90º temp outside even when the stock old manual temp gauge didn't show much. I pulled the fuel injection whatever its called out of the glove compartment and it said 180º. Why not run the fan all the time. Position it halfway in the shroud. I made my shroud out of two junkyard Toyota pickups welded to the right position.
Thank you. The temp does go over 200 and I"ve got the young man's cam in the old man's car. I"ve got phenolic spacers under the carbs.. The car loves the open road in gears 4 through 6. I have a 3.42 axle. But the new gas stinks even if you can get it without alcohol. Going to a rigid 6 blade and fabricating some sort of shroud is a good idea. But if I could stabilize the temp like it is in my 98 Towncar daily driver I could tune better.
Nothing has helped keep my temps in check more than a big, rigid steel fan and a shroud. Water wetter also helps, it's not a gimmick. My 324 runs ice cold 3 seasons a year in virtually all conditions, but will run about 190-195 in the summer with the air conditioning on when I'm rolling on the highway and my foot is in it to keep 75 mph. That's a stock radiator, a 19" 6 blade fan with no clutch, and a steel shroud I made.
Beautiful motor Stan. Do you have a pic of your fan and shroud? Is that the factory 4 blade? I've been looking at 6 blades but they seem to have 28 degree pitch while the stock fans with only 4 blades have more pitch and are known to pull well.
I had your same problem in my Ford; fixed it with a 6 blade fixed blade and a smaller pulley on the water pump. There wasn’t any water movement at idle thru the system in my engine. I do have shroud now that was manufactured out of plastic. I believe you could greatly improve your cooling with just a ring of plastic or aluminum 1/2 over the blade edge up to the radiator. It could be split. It would not be a true shroud but would pull air thru a majority of your radiator surface. One would not be too hard to do using angles of aluminum and pop rivets. A split hose or rubber trim against the radiator fins/tubes will help seal it and protect the fins. Another option we used on my sons car was from the Circle Track section of Summit. They have aluminum shroud kits for the size of the radiator body. We turned the one we bought vertically for his car. Most are 2.6” thick and you cut the hole in the body of it. A ring of aluminum come with it for you to cut. We also use one on his race car horizontal sized to the radiator bodies. See photo You can also go to a kitchen supply outlets an find baking pans that are about 3/4 to 1” thick with a rolled edge and add a split aluminum ring to it with pop rivets that covers 1/2 of the blade with the proper gap. I’ve used ALL these ideas and when and painted semigloss or satin black look great.
190-200 sounds perfect in my world. My current ride is 180-185 in traffic. Coldest engine I own. And that’s with no shroud and a flex fan. I’m doing everything wrong. Might change a t-stat to bump it up a little. I’m use to 210-215. Corn fuel boil? I’m running a pump with a return (500 caddys came with em) The engine that was 210-215 would boil (fuel) occasionally in traffic. Haven’t had that issue with the 500.
this is a good idea. If you can't find a pump with return for your engine, you can install a 3 barb filter (the small barb feeds the return line), 33040 for 5/16" and 33041 for 3/8". Run a 1/4" return line back to the tank.
One example. I’ve seen similar on 70s early 80s OE applications. (Pre fuel injection) Also rerouting or insulating fuel lines near a heat source is a good idea.
The return line is a good idea, bring cooler fuel to the carb. I’ve also had some success insulating the fuel line from the pump to the carb, or putting a line on that moves it further from the block and then wrapping it. Looks kind of ugly on a hot rod but it’s pretty cheap to try. It might be the carb spacers are “kind “ of working, but the fuel is too hot by the time it reaches the carbs.
I use a 17" steel 6 blade fan and a Walker radiator. after I installed the fan it made a huge difference in my temperature gauge, I don't have a shroud buy even in bumper to bumper traffic the hottest it ever got is 190. HRP
I now use my elec pump only to prime, I put on a stock mechanical pump and have dialed it down to under 4 lbs. All of this has helped. Nobody has voted for an electric puller so I guess it's time to build a shroud.
I'd be in trouble if I couldn't deal with 190...that's the coolest my Chevy II ever runs. Usually 200-220 or so when it's warm out. But the carbs get to ride in the breeze, above the hood, so I guess that helps. No inner fenders, either. It has a big clutch fan, but the shroud I build didn't seem to do much for it.
No, I took the factory 4 blade off and got a 6 blade from Speedway. It's nothing fancy, but it definitely moves more air. I pulled the 7 blade off a Cadillac 500 in a Eldorado years ago and put it on my 57 Ford and it fixed my temp issues, so I did the same thing with my Olds.
To significantly increase the efficacy of any fan all it needs is a lip to prevent the air being flung from the center of the fan outward. The shroud on mine does not force all the air drawn by the fan through the radiator like the one pictured above. Removing it makes it more noisy and less effective. 190 sounds about right, that is where you want to be for best burn on modern gas anyway. Phil
A fixed blade fan will pull more air at slow rpms then a clutch fan will, but the diameter of the fan is nearly as important as the number of blades on the fan. If your radiator core is 26" x 20" but your fan is only 16" in diameter, it will only cool the area in front of the fan, if you have no shroud, and even that would depend on how far the fan blades are from the radiator core. I would probably start by adding a fan shroud It needs to cover at least one dimension of the core, but covering the entire core would be better. It also has to be within 1/4" of the core and extend to 1/2 the blade depth of the fam blades. Summit has a couple universal fan shrouds available for reasonable cost. The fuel boil off is a separate issue. A return line will help that a lot. You might want to look at your fuel line routing to be sure the fuel line doesn't move the fuel through a high heat area, that could be your problem there.
Mopar used a pretty aggressive 7 blade solid fan back in the day. I never had an overheating problem when using one of those.
Make your own shroud from MDF, an old T-shirt and fibergl*** resin. I began with two 1" wide by 0.5" thick MDF frames; one the size of the radiator core and one surrounding (and touching) the fan blades, with MDF spacer blocks glued between 'em. An old T-shirt got stretched and stapled around the frames: I smothered everything in resin and added a layer of resin-impregnated mat on the inside. Then I trimmed 0.5" off both frames' inner edges; giving max core exposure and 0.5" fan clearance. Countersunk brackets attach to the rad/grille shell bolts. I sanded then sealed everything with a thin coat of resin. More sanding & primer. Them install.
The fan just moves air from the front to the back, and just like you and me, it's lazy. When it's easier to **** air in from the side between the fan and radiator than pulling it through the radiator that's what it'll do, so most of the air it moves is just circulated behind the radiator, not very much is actually pulled through the radiator. Add the shroud, force as much air as possible to actually go through the radiator, should improve cooling quite a bit and reduce under hood temperature as you flow more air through there, not just circulate the same hot air time and time again.
A 26x20 rad is 520 sq in . A 16" fan is 201 sq in. Without a shroud you're moving air through less than 1/2 your radiator . There are 16" dia . 2" thick electric fans available. If you feel the shroud is restrictive , you could install " trap door" flaps that would open at road speed .
The Jalopy Journal
