55.2-59 Radiator to fan clearance

[popeyestruck]

59 chevy stock 235. Adding A/C so I put in a bigger radiator . Champion aluminum. I have 3/8 clearance . Do you think this is too tight? Assembly manual says 7/8

[mr48chev]

3/8 just flat seems too close. 7/8 is tight.

3/8 doesn't give you any wiggle room for sheet metal movement or motor mount movement at all. Up through 59 these frames were designed to flex a bit over rough ground and things are going to wiggle a bit expecially on driveway entrance and exit ramps.

[leegreen]

do you have the long pump or the short pump with shallow pulley

https://www.jalopyjournal.com/forum/...nment.1270550/

is pretty descriptive of some of the options

[popeyestruck]

Using davis speed shop pulley 10036 that fits over the tall pump. If I use the short pump my pulleys wont line up. Davis says on their site if I have a clearance issue to email the, I am waiting to hear. Maybe they have a work around. Only other thing I might be able to do is knock the front off the big cage nuts where the radiator mounts . That might give me a liitle bit

[leegreen]

some of the aftermarket fans have blades that are flat on front for more radiator clearance

similar to this
https://www.summitracing.com/parts/der-19117

[popeyestruck]

Originally Posted by leegreen

some of the aftermarket fans have blades that are flat on front for more radiator clearance

similar to this
https://www.summitracing.com/parts/der-19117

Good idea. Thank you

[mr48chev]

Originally Posted by popeyestruck

Good idea. Thank you

I had one of those Ricky Racer pieces of Junk on my 48, they don't pull enough air to write home about.

A flex fan with full blades that don't stick way out in front should work though.


The clearance isn't a lot on this 56 235 that my students and I put in a 53 3100 back 30 years ago.

I used a V8 pulley and pressed the hub back on the shaft and cut the shaft off.

This photo after it had sat in their shed long enough to be a barn find.

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The blue ricky racer fan is the one that I had on the 48 for 15 years or more. It just did not pull enough air at and idle to write home about. the other one is one I picked up at a swap meet and plan to run on the 292. It has a lot more blade and is well built. Both are 15 inch. The big blades have about 1 inch more depths than the other ones do.

I still may run an electric fan (s) as the late sixes water pump and fan is somewhat lower on the engine than the early sixes are.

[1project2many]

My 57 has very little clearance between the water pump and radiator. It's roughly 3/8" which was not enough for me to feel comfortable using a mechanical fan. I opted for an electric pusher fan triggered by a thermostatic switch.

Even if you find a mechanical fan that works, you might want to consider an additional electric fan to help improve airflow over the condenser at low speed and idle.

[mr48chev]

I very honestly could have put an electic fan that was at least 12 or 14 inches in diameter above the mechanical fan in my 48.

I can't get a photo of the 85 dodge mini ram van that I use as a storage shed that has a pusher fan. that one has been out in the weather too long but one that matches the fan that was in the 91 Grand Caravan all wheel drive V6 that we had would get the job done.

[dsraven]

any mechanical fan without a shroud will be less effective. an electric pusher fan mounted in front may work, with a thermostat. a set of double puller fans may also work if spaced so the motors are offset from the water pump. setting the rad on the front side of the rad support would gain you some clearance but would likely need some hose mods. thats if the hood latch will clear etc. building a new rad support that sets the rad further forward is an option as well.

[leegreen]

I have dual electric puller fans on a factory AD rad in front of a 250 6. I went with dual as there was not room for a fan motor between water pump and rad.

The largest dual fans you can fit on the rad are dual 10". I have a shroud that covers the rad with only the 2 10" holes. This works OK, when the fans trigger they pull the temp down quickly.

I'm going to open the shroud up a bit more though, I think it will cool better on hot days (anything over 25C is hot for me) in moderate traffic, as it is the fans come on and off more than I'd like. They also come on quite quickly when you come off the highway. I have an override switch on the dash to just turn them on independent of the thermal switch, so I ran that on hot days last summer.

If I wire dual fans again I might go for two thermal switches so one fan comes on at a lower temp than the second, or wire two override switches so I can run one or both.

[dsraven]

or run dual fans so they come on with a stepped speed, so they start slower and as long as the temp is good they run slower, coming on full rpm when needed. that would require some wiring though, possibly a couple of thermo switches with different temp settings and possibly a resistor or dc motor speed controller set for a slower fan speed. of course, air coming is is only gonna be as easy as air can get out somewhere. no place for easy air escape means the hot air is just gonna circulate under the hood.

[leegreen]

I built the shroud to avoid air recirculating through the rad and to avoid using the poke through the rad zip tie mounting system the fans came with. Air can't recirculate without going under the front bumper and back through the grill.
When/If I open up the top left and bottom right corners of shroud I'll do some kind of grill / flap to stop recirc when the fans are on.



the fans are very effective in this setup, I'll guess they'd have worked fine just hung from the rad with no shroud.

My rad is angled back at the top so the bottom clears steering box, I would have had to use a very thin or small diameter engine driven fan

[mr48chev]

Well 60 years of working on cars and trucks an 70 years of reasonably well understanding what the older guys were saying about what was going on on a car or truck and that thing about the air recirculating back through the radiator is a totally new one on me. I'm not saying that it isn't posible but the likelyhood is so low it can't be measured. For that to happen you would have to have the routes that air normally flows out of the engine compartment blocked off so no air could flow out.

The shroud does make it so the fan pulls air through the whole radiator rather than just the circle behind the fan and that is what it is designed to do. That is why all of us with mechanical fans and no shroud normally see the temp go up when we are at an idle or moving slow because air is only being pulled through that circle in front of the fan and with those ricky racer blades I had on mine that wasn't much air. Hit 25 and you could watch the gauge go down but I have 120 louvers in the hood to help air flow.