This one's for OS :flipoff2:

After swapping in the new Hugh's 4 core I lost a lot of clearance between the radiator and the engine. Right now I'm running an electric fan with less then 1/2" clearance. Got to go, I don't want to toast another rad. I'm going to go with a flex fan. I've looked at a few options, if I run a standard flex fan, I'm not going to have much more clearance, maybe an inch. I've looked at some tight clearance fan that should net me an additional inch.

Now the Q, what is the ideal distance to have the fan from the rad? I know that without a shroud you need to have the fan as close as possible. I'm going to build a new shroud so this should not be an issue right? I'd like to have as much clearance as possible, call me paranoid but sheet I don't want to toss another rad down the drain.

Any of you guys swap in a fixed fan? What spacers did you use and how much clearance did you end up with?

Joe

Joe- Flex fans tend to "flatten" out at higher RPM's, not providing the pull though you really need. I've had the best results with the std factory fan and a good shroud.

I think Amanda's 78 has a fixed fan (no clutch) with a spacer. You could look at her's or I could get a pic for you.

Originally posted by jdjanda


Now the Q, what is the ideal distance to have the fan from the rad?

Joe

A fan will be the most efficient when 10-30% of the blade is out side the end of the shroud. Take a look at your stock shroud, it has a venturi shape to it. To get full use of the venturi the fan center line must be near the end of the shroud opening.

Originally posted by Old Scout


A fan will be the most efficient when 10-30% of the blade is out side the end of the shroud. Take a look at your stock shroud, it has a venturi shape to it. To get full use of the venturi the fan center line must be near the end of the shroud opening.

The stock shroud is toast :D Since I'm building a new one, I'll be able to setup it ideal. How far from the rad is too far?

BTW, Mark I have not been able to find a non-flex fan that is not designed to work with a clutch fan. I'd prefer a fixed fan, but don't want to run a clutch. Oh what happened to the old days when things were simple?

Originally posted by jdjanda



Oh what happened to the old days when things were simple?

Man- I hear ya!

Originally posted by jdjanda


The stock shroud is toast :D Since I'm building a new one, I'll be able to setup it ideal. How far from the rad is too far?

BTW, Mark I have not been able to find a non-flex fan that is not designed to work with a clutch fan. I'd prefer a fixed fan, but don't want to run a clutch. Oh what happened to the old days when things were simple?

Couldn't you take a "clutch" fan and use the spacer with it?

That's the trail-repair for when your clutch stops clutching.

I've only run a flex-fan once.. burnt up the motor because of insufficient cooling at high RPM/high-load/low speed.

Not again.

Plus a flex-fan will flex MORE when you do a water-crossing, and chew up the rad..

Fixed fan with a spacer. Noisy on the highway, but the most efficient at cooling on the trail.

Originally posted by jdjanda

How far from the rad is too far?



If the shroud is somewhat air tight there is no problem being any distance.

Found the dam thing, Flex A Lite makes them

http://www.flex-a-lite.com/auto/Race.htm

Looks like just what you need :)