Engine Cooling Systems and Components

Ok, photo of the bu fan. Pretty simple fare. I'll read further regarding how a fan should flow. My cooling problems have always been primarily at slow speeds.
 

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Not what I thought lou, guess I was thinkin' fullsize chev!

Anyway...I see the seal! That shroud on the chev is much more of guard ta keep yore hands outta the fan than a real "shroud" for air pullin'/pushin'.

I found some fans (aftermarket replacements) at my goto parts house Wednesday. But I didn't have a dam pump with me to test bolt pattern and all, as that's not why I was there!

These are derale "flex" fans but not really flexfans like I hate! They are an all steel "hub" section with riveted stainless blades, pich appears to be same to my eye as oem IH and the blades are equi-distant with no "offset" pair. Near identical to the hayden fans my other parts house keep on the wall.

And the "chrysler" pattern fan hub spacer is the correct one for IH apps as the centering snout on it is correct for the water pump hub and fan center hole.

I have a fan and water pump loaded in the truck now for my next town trip for test/verification, that will be either tomorrow or Sunday. I'll fit these fans to the pump hub, then all that's needed is jugglin' spacers to get the correct stickout and space the fan away from the air-off side of the core. Could maybe do this fromma spec sheet but I always prefere actual parts and first hand inspection!

Been on the phone today with monte...he's dealin' with the same thing right now tryin' to swap a big nut pump for an 8 holer and just discovered why I said the big nut fan will only fit a big nut clutch! And he's not gonna run a clutch, but his local parts house has fans to select from also and he knows not to use onena them dam flex units that's plastic and aluminum and a mankiller!
 
The whole idea of fan clutches was to save horsepower, and on some rigs that translates into mileage stats. It follows fan laws in that the volume or cfm directly follows rpm, the static pressure varies as the square of the difference say between condition 1 and condition 2, but the power varies as the cube Of the difference. Quick example, say a fan is running 1000 cfm at 1500 rpm with a 1 hp motor. You increase the speed 66% or go up to 2500, you'll get about 700 extra cfm, but the power needed now goes up to 4.5 hp, or in the case of an electric motor 5 hp to run it safely with a 1.2 service factor. Added to that, when a fan is boosted by say a positive draw or in our case ram air on the freeway, the power needed goes through the roof because it's working harder because of grabbing more air. See how these clutches come into play? I suppose with a 150 or so horsepower, losing 5 or 10 doesn't seem like much, but it's there. Our issue is finding reliable clutches.
I'm sure one of the folks at IH only would set you up with a fixed bladed one. I have found the IH 5 bladed fixed fan a whole lot quieter than the standard 4 bladed one.
 
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More good info, I would have thought that ram air would make a fans job easier not harder. I was using a 7 blade fan with curved tips.

This might be what mm was talking about.
rigid race fans

heavy duty steel cooling fan $26

lou as a side note the 3/16" was at one end of the impeller the other end was about a 1/16 so I was loosing more like half the flow. If you need to borrow a pump housing I have one handy.

Another note my engines water jackets are not in the best shape, even after the engine was rebuilt. I noticed they looked bad when removing a water tube trying to get a power steering bracket bolt in. I called and they said they used a caustic soda hot tank, but I don't think they did the heads.

I'm running the rmi-25 cooling system treatment Jeff sells to see how it cleans the insides up. So far it looks to be doing a great job by how clean the inside of the radiator is looking.
 
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That rigid fan from derale is the one I was looking at. Jegs/summit has them for $44 for steel blades and $49 for aluminum. When I next pull the Scout in and start pullin' a wrench again I'll check the impeller clearance first. If it's bad I'll correct that and hold off on the fan. If the clearance is good I'll do the fan. The clutch I'm now using is a napa/hayden heavy duty. The lockup is about 20-25% more than the stock clutch. It was installed as part of all this effort and no change in temps was noted. I'm hopin' hard that I have a pump clearance issue to be corrected.
 
Here is a picture of my new fan setup. I do not have a shroud because of the body lift, but that May change. I used a 18.5" flex-a-lite stainless steal fan and a 2" universal extension.
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Monte: yu shure got a purdy block. What are them 2 big black knockers in front, light buckets? Got a front side photo? I'm wonder'in how they look.
 
monte lauer said:
here is a picture of my new fan setup. I do not have a shroud because of the body lift, but that May change. I used a 18.5" flex-a-lite stainless steal fan and a 2" universal extension.
Click to expand...

I just made some aluminum plates to off set the shroud so it would fit. I used some "rivnuts" to pop rivit some nuts into the aluminum for the shroud to screw into.

Mine still runs warm. It was warm out this weekend and I saw the temps getting up to 205, not as hot as before, so I have made some improvements. But I would not want to take along trip if the temps were above a 100. Thinking about adding an extra bottle of rmi-25 to speed up the cleaning.

Edit... Monty what happed to the overflow? See how you insides look a bit tarnished, that rmi-25 with shine that up.
 
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Craig said:
I just made some aluminum plates to off set the shroud so it would fit. I used some "rivnuts" to pop rivit some nuts into the aluminum for the shroud to screw into.

Mine still runs warm. It was warm out this weekend and I saw the temps getting up to 205, not as hot as before, so I have made some improvements. But I would not want to take along trip if the temps were above a 100. Thinking about adding an extra bottle of rmi-25 to speed up the cleaning.
Click to expand...

Thanks for the picture. I have given some thought into doing exactly what you did. As of right now I still don't have a shroud to use, but when I find one I will either lower my radiator 2" or do what you did.
 
While we're on the subject of fans, I'd can some of those spacers as you can get a fan too close to a rad. The deal is that high pitched prop fans can paddle the air outward or radially at low speeds. Also, they don't have an even suction profile 'cause of different velocities across the blade length; consider a doughnut or bagel cut in half sideways for an idea of a suction side flow print. You put that real close to a radiator, the fan will print that flow right through the core and actually reduce heat exchange 'cause the effective flow isn't what it needs to be across the whole radiator. Because a fan doesn't sit square with the radiator due to the attitude of the engine being nose up, you'll get a reverse flow in areas or the cooling system is regurgitat'in some of the now hot air.
Moving the fan away, while counterintuitive, a couple of inches acutally helps because of a plenum effect. The plenum effect averages overall flow so that you'll actually have more flow across the whole Radiator's area. All my rigs have a fan spacing of 1 to 2 inches depending on vintage and radiator width. The 71's radiator fan is spaced 2".
 
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Greg, you bring up an interesting point and one that I wondered about this weekend with my new engine instal. How close is to close? Different fans probably have different distances that are optimal.
 
An absolute virgin, bone-stock oem sii/304 with the hd cooling package (a/c, three row radiator, and big nut clutch) has the leading edge of the fan blade tips set exactly 1-3/4" away from the air off side of the radiator.

My 1110 with hd cooling (big nut clutch and 3 row rad) but no a/c with the same clutch/fan package sits at 1-1/2", but the iso-mounts on the radiator package set it back 3/8" nominal, the gap between the radiator frames and the core support have been filled with 1/2" thick closed cell neoprene tape.
 
Monte, fan pitch probably affects distance more than anything. I'd start with a stock distance, or at least what'll clear the water pump and belts. All that I've seen is around 1" or so to 2". Maybe the photos are skewing the perspective, but the fans look awful close for me.
 
Thanks for the stats Mike. Did the curved tips like in Craig's lead away from or to the radiator? My memory is ail'in in that retrieval.
 
Craig, what is that fan adapter? It appears you have the factory clutch type fan bolted directly to the pump hub with a shiney black adapter. Is that available somewhere?
 
lou said:
Craig, what is that fan adapter? It appears you have the factory clutch type fan bolted directly to the pump hub with a shiny black adapter. Is that available somewhere?
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I got a used one from Jeff, but I sure you can get one at the local auto parts store, or summit/jegs. I see you found the az pump re builder I was talking with. Nice guy and knowlagable too. Here's my old cluch fan:devil:
and a few pic of the fan spacer

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Wow! Them thangs is huge! I bet they brighten things up a bit.
I sure like the color of your Scout, looks way good all over.
 
Found this, here

That's like a 1/4":icon_eh: seems a bit tight, my old Chevy is like a 1/2" will measure tonight.
 

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