I'm installing a 305 SBC in my 1955-2 3600 truck. I'm finding that the clearance between original engine fan and radiator is CLOSE. Is there any downside to using a single or dual electric fan bolted directly to the radiator?
Plenty of downsides- - - -mostly with the pusher fan acting like an air flow restrictor at highway speed. How close is "CLOSE"- - - -OEM fans on some stovebolts were within less than one inch of touching the radiator core, which was no big deal as long as the motor mounts didn't get sloppy. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
How much clearance is there between the fan hub and the water pump housing? It's a pretty simple matter to set the water pump up in a press with the back plate removed, and push the hub back a little. The hub is just a press fit on the shaft, and it's done frequently with stovebolt six water pumps to get a little more radiator clearance in early 50's pickups with post-55 engines. Another option would be to space the radiator forward a little. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
When you get to 1/2 inch...."about" is NOT good enough because a true 1/2 inch may be enough. So it would save you a lot of work, time and money if you would get an accurate measurement for us. It also depends a WHOLE lot if the 1/2" is to a nose of a pulley or to a fan blade. If you can fit a 1/2 piece of plywood and still spin, you are in. (1/2" plywood is 15/32). As Jerry says, no funny business with worn out mounts. Something seems fishy here, I have done this on 55.2-59 and don't remember that tight, believe you can move motor closer to firewall.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Here's an electric fan attached to a fan shroud made from an aluminum cookie sheet found on ebay in the exact dimension of my '32 Ford roadster street rod radiator core. This cookie sheet cost less than a similar size piece of sheet aluminum and comes with rolled edges and an offset rim just like a "real" fan shroud. This shroud works even better now with large round holes cut in the corners covered with very thin sheet rubber to open at highway speeds for better air flow and to close when the car is moving slowly or stopped. The cooling options are endless without buying any expensive parts.
The ducting in the foreground is a home made cold air system to direct cold air to a plenum surrounding the air cleaner.
Thanks bartamos. To me the fun of this hobby is in doing projects like that at home. With a lathe, milling machine and tig/stick welder anything you can imagine you can make from the humblest of materials, even a cookie sheet.
This is my first sbc+700R4+driveline job so I'm learning as I go and sure appreciate experienced advice. I presently have the engine and tranny suspended in the engine bay from a hoist. I'm trying not to modify the rear cross member and the tranny pan clears it by about 3/4" and the distributor clears the firewall by about 3/4" too. I have the carb mount level over a level floor but the engine fan seems to point somewhat upwards … which makes radiator clearance issues more of a concern.
Cookie sheet, yeah that’s brilliant. I bought a cake pan for doing a firewall notch, but never heard of the cookie sheet before. That’s what I call a $10 problem solver. Is it a non-stick pan? LOL.
Another sneaky trick is to use part of the stamped steel pan of an inexpensive wheelbarrow as a firewall extension around a V8 conversion on some of the older vehicles with limited engine compartment room. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Snowman, the motor should be sitting with carb/manifold at level. The fan should then arrive at parallel to rad or possibly slightly angled up. Very slightly. If you are still in the mock up stage, fix that. Your 3/4 clearances are OK. Your questions are electric fan issues and rad clearance. If you get the rad clearance to 1/2 min, I guess the electric fan is not necessary. So let us know the clearance to rad with mechanical fan blade/water pump pulley if you need any more opinions/suggestions. Be sure to always check your level tool for accuracy.
The way you do that for horizontal accuracy is: put it on a stable surface and read the bubble location to reference marks, no matter where it settles. Then rotate the level, (keep it on the same foot print of the surface), 180 deg and see if the bubble is at the same place, only on the opposite marks. The rotation of level is about the vertical (Y) Axis. Just spin it like a top in other words. Vertical bubble accuracy check is same way on a wall.
I know, everybody has a digital level or their iPhone app......but me. Whatever.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
