Fan clutch choice

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canyncarvr

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I understand this is more a crap shoot than not. Might as well start with some educated guesses from folks more familiar with the item than I am.

I am looking to change my decades old flex fan, need to choose a clutch. Temp-controlled is a given to me, but...the regular, heavy-duty, extreme duty types? I don't know.

My 340 is a rather mild build: 10:1 iron heads, 286/290º cam, A833, 4.56 geared. Headers are ceramic coated, done to reduce heat...but it certainly gets hot under the hood. Radiator is a 3-core vertical copper/brass...OEM stuff. OEM shroud will be used.

IF a regular duty clutch (say 60-70% engagement) has a decent chance of working, I will give it a try, just to avoid the huge racket a 'stronger' clutch makes.

Maybe a 'heavy duty' (say 70-90% engagement) is the first reasonable choice and a standard duty is a waste of time?

Going to use a five-blade 4140063 fan. I'm sure there are opines on that, but that's not the question.

Thanks!
 
I think the heavy duty is the best choice, the one you chose will be based on the clearances on the front of the engine. The 2747 is likely your best choice if it fits.
 
The 2747 is a tight go. Spec'd at 3.38", I have 3.50" in front of the pulley.

Maybe I don't have room for one at all. Mancini's is listed at 3.31"; 3-5/16" anyway.
 
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The 2947 is thinner, forget the numbers, but it is a major pain to install. I would think you would want about 1/2 gap to change the belt.
 
Thanks. I missed that one.

Yeah, at 2.7" it is short. Just make it 2", maybe attach it with 'extra strength' velcro 'cuz there would be zero room for bolts!

I thought I put in a flex fan because it was kewl at the time. Maybe I used it because there was no room for the clutch. It is a hi-volume Milodon aluminum pump on a '69 block. That may have something to do with it. Wouldn't think so. I recall a fuss with engine mounts.

That swap ('69 drivetrain into a '73 car) was a LONG time ago.
 
Unless you are trying to gain 1/2 mpg just go OEM fixed 7 blade.
 
Putting 2 and 2 together, I think that you have a stock 340 in a 73 A body with a stock V-8 radiator, correct???
 
For tight clearance, some people use a fan-clutch for a Jaguar. The one on my 1985 M-B 300D is also thin and has the same bolt pattern and water pump snout diameter, as I recall. But, even that was too thick for my 1965 Dart w/ 273 since I used the later aluminum water pump (1" thicker) so I could only fit a plastic flex fan. You should have more room to the radiator in a 1970.
 
Or, you could put a '69 water pump on, gain 3/4's of an inch for room. This would necessitate a radiator change. 2947 Hayden fan clutch, mopar fan, Milodon pump, Cold Case 22" radiator.

20201101_121846.jpg
 
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I did have to change pulleys. Still have the '70 dampner and timing cover. If you have a problem, sometimes it does pay to look at it from all angles. I needed a new radiator, and knew about the clearance issues with fan assemblys, so I got what I needed to do it. Still haven't gotten a '69 timing cover and balancer. I can read my timing tape for now, and haven't had a cooling problem yet. I may need a shroud for the summer heat, we'll find out next summer.
 
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I understand this is more a crap shoot than not. Might as well start with some educated guesses from folks more familiar with the item than I am.

I am looking to change my decades old flex fan, need to choose a clutch. Temp-controlled is a given to me, but...the regular, heavy-duty, extreme duty types? I don't know.

My 340 is a rather mild build: 10:1 iron heads, 286/290º cam, A833, 4.56 geared. Headers are ceramic coated, done to reduce heat...but it certainly gets hot under the hood. Radiator is a 3-core vertical copper/brass...OEM stuff. OEM shroud will be used.

IF a regular duty clutch (say 60-70% engagement) has a decent chance of working, I will give it a try, just to avoid the huge racket a 'stronger' clutch makes.

Maybe a 'heavy duty' (say 70-90% engagement) is the first reasonable choice and a standard duty is a waste of time?

Going to use a five-blade 4140063 fan. I'm sure there are opines on that, but that's not the question.

Thanks!
My choice would be - none.
Why would you automaticly give up 20 - 40 % of your cooling air?
If you want a crappy cooling fan just get an after market electric fan.
 
No email alerts. Must've missed one.

Putting 2 and 2 together, I think that you have a stock 340 in a 73 A body with a stock V-8 radiator, correct???

Not exactly. It's a '69 engine with an aluminum 'front end'. Not sure of the 'stock V-8 radiator' part. The OEM rad was ruined by a radiator shop when they cleaned it. As I recall, I bought an OEM replacement to fit the '73 front end on the '69 motor. It was an A/C car, so I think it was a 3-row to start with. I never measured what, if any difference, there was with the '69 engine and its different mounts in my '73.

None of that is pertinent to the original question, but don't want to leave the question unanswered, either.

Is the car staying cool at highway speed?..

Yes, it does. My question had nothing to with cooling or not, though, just suitable clutches for replacing a flex fan with an OEM style fan.

My choice would be - none.
Why would you automaticly give up 20 - 40 % of your cooling air?

Because I don't want an OEM style/steel/heavy fan directly attached to the front of my water pump.
 
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I know this is not what you're talking about but I'm going to throw it out there anyways.. I'm having great results with a quality electric fan...
 
Because I don't want an OEM style/steel/heavy fan directly attached to the front of my water pump.[/QUOTE]
They clutch will add even more weight.
I have run large factory mechanical fans for years never had a problem with water pump bearings.
 
They clutch will add even more weight.
I have run large factory mechanical fans for years never had a problem with water pump bearings.

There is more to the 'directly attached' part than weight, as in spinning all the time in real time.

Still a valid option, though (direct attachment).
 
There is more to the 'directly attached' part than weight, as in spinning all the time in real time.

Still a valid option, though (direct attachment).
I've always called it the whirling blade of death! LOL so nice to stick your hands down in the engine compartment with the motor running for instance like a timing light situation....
Good luck...
 
I've always called it the whirling blade of death! LOL so nice to stick your hands down in the engine compartment with the motor running for instance like a timing light situation....
Good luck...
How many times have you seen people who were going to stick their tongue in an electric fan?
 
Make sure to have your 2000 AMP alternator on hand, then ask how to wire it, how to mount it, why don't the belts line up and how do I get my led lights to work with the $100. fits all cars wiring harness. I am thinking that the poor guy has all of the info he needs to figure it out. He can always pm someone if he would like to go in a certain direction.
Just saying.
 
...you have a stock 340 in a 73 A body...

Gee. I think that made me feel bad. :( Used to be a 290º@.008" duration cam was close to as hot as it got on the street.

I'll have you know I have over 7" of vacuum at idle!!! ;) ..not eight, but over seven.
 
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I am thinking that the poor guy has all of the info he needs to figure it out. He can always pm someone if he would like to go in a certain direction.
Just saying.

Yes sir!

The 2947 is thinner, forget the numbers, but it is a major pain to install.

The 2947 would do the job. Plus, I'm sure Mike would be glad to let me watch him put it together right.
 
The pain part is 4 short bolts are difficult to turn into the hole. The next time it's off I may make 4 short studs. The picture in post #11 doesn't really show the difficult part, how close it is.
Was not trying to make you feel bad, but poke fun at the measures some people will go to draw you into their side show.
 
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