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Discussion Starter · #1 ·
I've been reading the ongoing debate between engine-driven fans, flex fans, electric fans, etc. My CJ5 has an engine driven fan bolted to the water pump pulley, and it has no shroud or clutch. So my questions are two-fold. First, did 77 CJ's have shrouds? Is there a shroud that will fit the stock radiator/fan? Second, it seems to me that a clutched engine-driven fan would be the best all-around...faster warmup, no need to switch or unbolt for water-crossings, and dependable, engine driven performance (just like on the big mack /wwwthreads_images/icons/smile.gif(just for CJDave)). I'm aware that 4banger jeeps had a temp-controlled radiator fan clutch on them, was it ever an option on the v-8's? Is there a clutch that will fit the bolt pattern/space? Or how have our resident jeep-gurus cooled their engines with mechanical drive fans?

Measure once, cut twice...or is that the other way around?
 

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Full sized Jeeps with V8s had a clutch, ala Grand Wags, Cherokees, J trucks...

Im not sure of V8 CJs, as my 304 had a cheap flex fan, I didnt like it so I yanked the whole engine to make room for a 360 ( with a new clutch fan) from a 1980 Cherokee...

My CJ didnt have a shroud either( the 1980 cherokee did, maybe it will fit!!), but its pretty mangled as far as wonderful to rectify DSPO mods go...





ozarkjeep
1977 CJ5 looking for a Hard top near NW Arkansas!
 
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Discussion Starter · #3 ·
As far as I know every vehicle made comes with a fan shroud....an engine fan without a shroud is almost useless because the shroud allows the air to flow through the fan, without a shroud the air just flows around the fan blades taking the path of least resistance. I would get a shroud on there ASAP.

I don't want to get into the whole debate of which type of fan is better...ELECTRIC....but I have an ELECTRIC fan and I am very happy with my ELECTRIC fan. But like I said I don't want to get into the debate again..ELECTRIC

absolutjeep
http://members.tripod.com/iluvjeeps
 

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not every vehicle made, My MGB doesnt have a shroud, in fact it only has 2 electric fans, and you cant drive that baby slow in the summer either ( it gets to HOT)

I wish it had a CLUTCH fan

CLUTCH



: ) haha

ozarkjeep
1977 CJ5 looking for a Hard top near NW Arkansas!
 

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My $.05(keep the change)/wwwthreads_images/icons/smile.gif
If you don't do alot of neck deep water crossing go with the clutch fan for all around performance. It's the hands down no worry , no hassle winner.
Just make sure you buy a thermostatic clutch and not a centrifical one(these are garbage and do NOT last/wwwthreads_images/icons/mad.gifdid I say they were JUNK?!)
I don't know if it came w/ a shroud but my 85 one fits my buddies 79 v8 cj7 and 76 cj5 w/a 258 so I'd say you could use one too/wwwthreads_images/icons/smile.gif
No v8's had a factory electric fan on them...just too dern high tech for jeep in dem oldin days/wwwthreads_images/icons/wink.gif
And last most of all the 6 or 8 cyl jeeps that I have run across have the same bolt spacing and wp rotation and share it with a sb chevy , so just check radiator clearence and wip out the tape and head to your local junkyard.
Hope this helps

85'CJ7 258 4" runnin33's
 

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So how many big Macks (the truck not the burger) have you seen on the trails and/or making water
crossings?

Explain to me how the clutch fan is going to make that water crossing without disconnecting it. Are you
going to wait on the side of the stream until it gets cool enough to disengage the clutch? Even then, it
will still spin since it's mounted on a rotating shaft and the air doesn't provide enough resistance to stop
it. The water will stop it if the clutch is disengaged, but how quickly. Remember Newton and objects in
motion tend to stay in motion?

As to the shroud, absolutjeep hit on the problem but missed the target with the path of least resistance.
As long as the air goes through the radiator, it doesn't care whether it's through the fan or around the fan.
The problem is that, without the shroud, the edges didn't cool and the coolant takes the path of least
resistance through the hottest part of the radiator. Hotter fluids flow better. Even this wasn't a problem
until the mid '60s muscle car era, when the engines got bigger and the grilles got smaller.

You said you had radiator fan questions, the answer to the second part is use electric for a number of
reasons, but you don't seem to like the answer. As far as the MGB, I doubt the problem is the electric
fan. The biggest problem is the itty bitty grille opening, a problem you don't have with the Jeep. Still,
the electric fan won't make up for dirty radiator (inside or out), bad thermostat, belt slippage on the water
pump, etc., etc.



 

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Yep, the '77's had shrouds. I have been told that the reason you don't see a lot of older CJ's with shrouds is because they were made very thin and tend to rust out and disintegrate after about 10 years. I had no success finding any used ones. You might be able to order one from a dealer, but I hear they are getting scarce. I eventually decided to go electric anyway.

'79 CJ-7
 
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Discussion Starter · #9 ·
Actually, the system that I had on my Mack dumper would have been a great idea for a Jeep if it was only smaller. It worked like this, it was air actuated when it needed to engage and a sensor in the water jacket kicked it. When it was not, it free wheeled.

Now if you did have something like this on a Jeep, you could install an air valve to allow air to engage or disengage the fan. When your river running, kick it out. When ground pounding, kick it in and you have a thermo clutch fan.

I personally use an electric fan that does just exactly this. It came with its own shroud and thermostat and has a disconnect switch for water fording.

My thoughts and what works for me.

 

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/wwwthreads_images/icons/smile.gif the early Ford trucks had an electric clutch fan that did that also. And if you don't think some HP is going to the fan, just listen to it engage.....belts squeak and RPM goes down. We always figured 25 HP or roughly a gallon of fuel per hour for the fan./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless I've made 'em up myself.
 

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i have a shroud on my radiator but it's not metal. it's some sort of fiber reinforced something. it is somewhat easy to chip. maybe that's why they don't turn up in junkyards.
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Yep, the '77's had shrouds. I have been told that the reason you don't see a lot of older CJ's with shrouds is because they were made very thin and tend to rust out and disintegrate after about 10 years. I had no success finding any used ones. You might be able to order one from a dealer, but I hear they are getting scarce. I eventually decided to go electric anyway.

'79 CJ-7

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner
 
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Discussion Starter · #13 ·
As far as a fan shroud goes, for several vehicles I've owned over the years I made shrouds. Real easy to do using the sheet metal
that is used for heating and cooling ducts, and it is cheap too. Easy to work with, you can cut it with a snips, easy to form to make
a lip for bolting on. Should take an hour or two to make one for your Jeep.

Brad (from the 4 Wheeling center of the universe, 4 corners USA)
 

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The shroud is important when the fan (either a clutch, straight mechanical or electric) is engaged and pulling air. It allows the fan to develop the proper suction to draw the right flow of air thru the resistance the radiator (and the a/c condenser, if so equipped).It is important that the fan is centered in the shroud as well. Especially since all these fans under discussion are axial flow, which are far inferior to centrifugals when it comes to pressure developement.

Please notice that I'm NOT getting into the clutch vs. electric contraversy.

Best Regards /wwwthreads_images/icons/smile.gif
 

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Just to put in my .02 about the fan shrouds..... I bought a ' 75 CJ5 new with a 304 w/ 3 speed, and it never had a shroud. My ' 77 didn't have on either, but I didn't buy it new. I was also a 304 w/ 3 speed. My ' 72 CJ5, ' 72 Commando, and ' 84 CJ7 (all 6 cyl, standard transmissions) had no shrouds, nor does my ' 80 4 cyl have one. I think shrouds came along with pollution controls and other things the tree-huggers made them put on Jeeps in more recent years. I don't believe they were on the ' 77's new. Unless they came along with A/C for better cooling. Did they put A/C in Jeeps in ' 77?

Loose nut behind the wheel
Another right-wing conservative.....
Born and raised in Jeep-Town
 
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Discussion Starter · #17 ·
Farm Jeep:

You can still order a radiator shroud from the dealer, I know guy that did for his '78/304 just a few months back. I forgot what he paid for it, I wanna say around $75-100. He still has the part number, b/c he had to go round and round with the dealership. Let me know if you want his e-mail address for the part number. Collins Bros. may have them too, but their price may be about the same as the dealership's. I run in the river fairly regularly and I use a fan clutch. You can pick up a fan clutch and clutch fan at NAPA or other parts house that will fit your 304. The fan clutch is much better that a flex fan, or a solid finned fan with a spacer, in water. The clutch fan may not stop immediately when it hits water, but it will stop. The flex fan doesn't. It continues to churn water EVERYWHERE under the hood shorting electrical connections, shooting water in carb and it will eat through the radiator if it bends when it hits water. IMHO, with the shroud and a clutch fan you ought to be okay in most water situations. I've never run an electric and I'm not saying a clutch fan is better or worse than an electric. I am saying a clutch fan and shroud can be put on your CJ easily, and you may be right, it may be best all around solution.
Just my $.02.
Shain

 

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I think the ac and polution thought may be correct - the hp-strangled motor, driving air pumps, compressors, etc, produces more heat, needing more cooling. (??)

My old 67 impala w/327 had a shroud (had ac too), don't remember what the 64 w/283 had, my 79 ford truck's got one. The MGB (I had a 79) doesn't produce a whole lot o' heat anyway, and those 2 fans should keep it plenty cool - I drove mine for many years without issue. My older 74 MGB GT had a mechanical fan, and no shroud, or clutch.

If you're gonna do a lot of water crossings, get an electric (a good one ain't cheap, though, like $200). If not, I'd go with a clutch. I've crossed some deep water with my YJ, and if you keep rpms low, you shouldn't have a problem. I've read that a mechanical fan is best at drawing air. Perhaps it's the rigidity of the blades, or the angle that they are at.

Pete

88YJ, 4"susp, 33"BFGMT, 9k#winch, rear homemade swingout, reb.258, 999, 4.10, weber32/36, GMHEI.
 

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I forgot to mention that shrouds are very good for keeping your digits where they belong. I've heard it said that you can stop a clutch fan with a bad clutch with your fingers while the engine is idling. I'll NEVER even try to do that; my hunt and peck style typing would definitely suffer from any mishaps./wwwthreads_images/icons/tongue.gif
 
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Discussion Starter · #20 ·
Well, this was a few years ago, but I saw an lift operator at the grain elevator in Lockport, IL let a truck down all the way without letting the driver get in and the truck rolled down into the canal...that was a deep water crossing...but seriously, I know engine driven fans suck hp...but I'm not drag racing anyone anyhow... Everything heavy-duty and reliable that I have ever seen has had a clutched, engine-driven fan. I'm aware that electrics work great for some (and in the end, I may end up trying one), but I'd rather stick with an engine-driven fan purely for reliability and simplicity. As far as the water stopping the fan...if it is a thermal clutch, even if the clutch is engaged, the cold water shocks the clutch and they release rapidly...moreover, water provides far more drag than air (for obvious reasons) and the inertia of the fan blades (and the associated forces causing them to stay in motion) is minimal, as it is directly tied to the minimal weight of the fan itself, and not tied to the inertia of the motor/etc. The parasitic rotational force put upon the fan even when the clutch is disengaged (by way of the rotating shaft it is mounted to) is insufficient to spin the fan if the fan is in water. The downfall of non-clutched engine driven fans (stock, flex, or otherwise) is that they have continued direct rotational force applied that causes them to become impromptu and weak propellers, whose large area (designed to work with air, not water) causes them to cross the gap that should exist between the fan and radiator...elimination of the continued rotational force (save for the aforementioned parasitic drag from the shaft) should make this a non-issue in most instances.

On the other hand, while I am still a strong believer in engine-driven fans, the careful prodding of many of the jeepers who I repeatedly see displaying great jeep-guru wisdom on this board in the direction of electric fans means that I will certainly investigate that option carefully before I run out and buy the clutch.

Measure once, cut twice...or is that the other way around?
 
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