My radiator has an electric cooling fan that I can switch on or off. It’s only needed when idling for a little while. It suddenly dawned on me that it needs a shroud . The 4 blade fan only covers the bottom half of the radiator. I could probably put a piece of aluminum over the top half or shape one some. Advice?? Thanks.
Last edited by Gdads51; 02/21/202610:13 PM. Reason: edit title to clearly state topic
1953 Chevy 153A 3/4-ton Working on my project since 2015 Follow along in my DITY
I beleive there are others that have more knowledge but is your water pump and fan the low version that is best replaced with a relocated pump and fan closer to the center of the radiator.
If you was a shroud fabricate a box that is open to the radiator out to the mid point of the fan blades with a hole slightly larger than the blade diameter attached to the radiator support.
My 250 in the '37 sets just like that, the fan blades go below the radiator core. I made a shroud for mine out of sheet metal, later this morning I will get you some pictures off my other computer.
When I install A/C I added the shroud. It's made from 18 gauge sheet metal. I soldered the seems along with rivets to hold it together. The fan was a 18" diameter flex fan from a local swap meet. The key to a good shroud is to keep it off the core enough so the air has room to flow through, make the turn and exit by-way of the fan. This summer I replaced the 18" flex fan with a smaller solid steel, 6 blade, 17" diameter from Vintage Air the A/C company. I figured they would know about air flow, the price was right, and the spacing of the blades was 50% forward of the mount, and 50% rear of the mount, most are not split like that. I don't know if the shroud helped or not, I never had issues with A/C till last summer when it got really hot out. The smaller solid fan moves twice the air the flex fan did, it will idle all day now and not heat up. At the same time I changed fan sizes, I changed to a smaller diameter water pump pulley, this speed up the fan 175 rpm at idle speeds. I left about 1/2" to 5/8" clearance around the fan, and about 1/2 way in and out. Not sure the in and out spacing is super critical, but to far in the air won't be able to get out. If you keep the electric, move it to the top so it doesn't block the mechanical. Vintage Air didn't have a 16", next size down was 15", a 16" would have been plenty with a correct sized shroud, 15" I felt might have been to small so I went with the 17". The 17" shroud is just the same only it has straight sides and fits a littler closer to the fan blades. The fan blade is really close to the harmonic balancer bolt, maybe 1/8" or a little more! The smaller diameter water pump pulley is off a short water pump small block Chevy engine, it lines up really close to the stock 6 cylinder balance grooves.
Edit: The core is 17" across, two row aluminum. Shroud is 2" out from core. The smaller shroud ( not shown ) has the center lip bent outward, the one shown, is towards the core. I actually made a mistake and had it flipped over when starting to bend the sides. The circle cutout needs a lip to add strength, if you are a good welder, a round rod welded to the edge would also work.
