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2/25/2018 10:03 PM  #1


Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

If you're like me, you've occasionally cogitated the best cooling setup.  I'm running a 2 row aluminum radiator, which has a core thickness of 2-3/4", which is about equal to a traditional 4 core copper radiator.  For a while, I've wanted to run a clutch fan with one of the 3-1/2" improved fan shrouds.  The 3-1/2" shrouds are a big improvement over the stock shrouds in that they cover more of the radiator and they are deeper, which translates to better suction from the fan.  I like a thermostatic clutch fan (as opposed to a non-thermostatic clutch) because it only engages when it's needed, and freewheels at only about 20% or so engagement when it's not needed.  Here's a primer from Hayden on fan clutches: http://www.haydenauto.com/featured%20products-fan%20clutches%20and%20fan%20blades/content.aspx

To my mind, if you're going with a mechanical fan, a thermostatic clutch fan is the best overall compromise in that it cools about as well as a non-clutch fan when it's needed, but saves power and gas when it's not needed.  The problem has been that the stock replacement fan clutch (Hayden 2710, standard duty) was designed for the stock shroud.  Therefore, on my 2-3/4" thick radiator, it's shaft is too long and places the fan too far into the 3-1/2" shroud for optimal cooling.  Searching through the Hayden catalog, revealed the answer.  Hayden also makes clutch no. 2711, which appears to me to be the only other clutch offered by them that will mount to the stock Ford water pump.  This clutch is also a standard duty clutch, but has a shaft length that is shorter.  See below for a comparison between (left to right) the stock 1965 A/C fan clutch (C4AA-C1), the Hayden 2710, and the Hayden 2711:
http://i67.tinypic.com/m4so3.jpg

Curiously, although the Hayden 2710 in the middle is listed as a direct replacement for the 65 Mustang V8, it's shaft is a little shorter than the stock 65 fan clutch, but still too long for my application.  Although the Hayden 2711 on the right is only about 3/8" shorter, that's enough to place the fan almost halfway in and halfway out of the 3-1/2" shroud with a 2-3/4" radiator, as is shown below:
 http://i66.tinypic.com/db2xc.jpg

One more thing - if you're in the market for one of those 3-1/2" fan shrouds, I recommend the one from Rhino Fabrications:  https://rhinofabrication.com/product/1963-1966-falcon-ranchero-comet-fan-shroud/.  It's ABS, is thicker than some of the others and is made by them in house.  Because my aluminum radiator came with an engine side flange, I was able to mount the shroud on that flange and didn't need the Z brackets used to mount a shroud on a stock radiator.


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2/25/2018 10:19 PM  #2


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Great info. Especially the picture of the 3 side by side.  I wish I could have found something like that a couple of months ago.  http://cdn.boardhost.com/emoticons/happy.png
Did you have any problem with pore machining on the water pump mounting flange of that 2711??  I bought one from NAPA and it way out of spec and could not be bolted up.  Then I bought one from O'Reilly's  and it to was a little off (better than the Napa one) I still had to use my die grinder to get it to bolt up properly.  They were both obviously made in the same factory and had the same part # printed on the front of the clutch.

 

2/25/2018 11:59 PM  #3


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Daze wrote:

Great info. Especially the picture of the 3 side by side.  I wish I could have found something like that a couple of months ago.  http://cdn.boardhost.com/emoticons/happy.png
Did you have any problem with pore machining on the water pump mounting flange of that 2711??  I bought one from NAPA and it way out of spec and could not be bolted up.  Then I bought one from O'Reilly's  and it to was a little off (better than the Napa one) I still had to use my die grinder to get it to bolt up properly.  They were both obviously made in the same factory and had the same part # printed on the front of the clutch.

Both fan clutches came from O'Reiley's and were made by Murray and (assume a Hayden re-brand) they carry the same 2710 and 2711 Hayden part numbers.  I didn't have any problems with the machining of the shaft, and the fan spins true. 

I should add that the shroud takes a 17" fan.  The only standard rotation 17" clutch fans I could find were a Derale 17117 and a Flex-a-lite 6717.  The Flex-a-lite fan has aluminum blades riveted to a steel hub.  It's lighter but has a limit of 4,000 rpms.  I noticed that a number of other aluminum bladed fans have this same rpm limit.  The Derale is steel blades riveted to a steel hub and has a 8,000 rpm limit.  The Flex-a-lite is noticeably lighter.  Because the standard clutch only engages at 60-70%, it would probably not see the rpm limit bolted to my engine, but I went with the heavier Derale to be safe.  CJ Pony and others sell the Flex-a-lite but don't note the rpm limit.
 


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2/26/2018 5:58 AM  #4


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Good info, thanks. Which radiator are you using?

 

2/26/2018 9:45 AM  #5


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Chaplin wrote:

Good info, thanks. Which radiator are you using?

The radiator is an aluminum 2 row radiator that I bought off ebay.  I like it because it has die-formed tanks so at first glance it looks similar to stock.  I don't see the vendor there anymore, but there are some similar ones being offered.  I imagine most are welded by teenage girls in China but mine looked pretty good and so far hasn't leaked.
 


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2/26/2018 9:56 AM  #6


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Great minds think alike I just went through the same thing with my galaxie.  These are the posts I made on my Galaxie forum

Found more parts (not for a 62 Galaxie) to put in my 62. Clutched fan

Daze wrote:

For those of you that have been here a while you know that I am all about customizing my car and using parts from any make, model, and year to maximize performance and function.  To that end I have found another upgrade.  My car is currently setup with an aluminum radiator, 302 and mechanical fan.  I was able to use foxbody Mustang engine mounts to drop the 302 into my 62 without modification.  The only issue is there is not a lot of space between the front of the engine and the radiator (about 3.5")  In order to mount the fan I am currently running I used a short spacer and then a 17" flex fan.  System works fantastic, moves a ton of air but it is also very loud and the constant spin of the fan eats HP.  Being its a small block in a big car I need all the HP I can get.  

A simple solution to this issue is a thermal clutched fan.  The problem is most of them take up more space than I have.  The key word there is most as I think I found one that will work.  As You know most parts places want year make and model to find parts so it can be a challenge to find the correct part based on specs and not the car it was designed for but I have figured out some good ways around that.  I went to Summit Racing and looked up fan clutches.  A bunch came up, problem is their web site does not offer any measurements so I then took each part # from Summit and input it into Napaonline.com.  The Napa web site is one of the best I have found to have measurement and other fitment specs. After checking a a dozen or more I found the shortest one they make that is still a 4 bolt for both the water pump and fan.  Napa's site listed a  fan mounting height of 1.4" but did not give me the entire height including the clutch piece so I went to Napa and measured one.  Looks like 3" which should just barley fit.  Original car this clutch was used on was an 1980 Cougar among other applications.  I then found an aftermarket 17" fan that will bolt up to this clutch and ordered it.  I will take some before and after pix and report back how it all worked once the parts come in and I get them installed.

http://imageshack.com/a/img922/5694/5itTDz.png


http://imageshack.com/a/img922/4772/3l81EE.jpg

Daze wrote:

Finally got the fan in the mail and picked up the clutch from Napa.  Here is a pic of it all put together, next to the fan that I am replacing.  I already did a test fit and the clutch will be about 3/8" from the radiator.  a little closer than I would like but acceptable.

http://imageshack.com/a/img923/676/QSnRm1.jpg

 

Daze wrote:

got it installed.  Its a little bit quieter and should save on power.  Have not had a chance to do much else with the car but I assume it will keep it nice and cool.  seams to draw a lot of air even at "cold" speed.
https://imageshack.com/a/img922/8321/HpM9pT.jpg

 

2/26/2018 11:53 AM  #7


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

I was doing some digging for the same thing on my car and stumbled across another part number that is shorter than  a Hayden 2711 on another site. I made a spread sheet to compare. Its Hayden 2765. Your Derale fan has a dual bolt pattern that will mate up to this clutch.

http://i64.tinypic.com/veuf10.jpg

http://fepower.net/simplemachinesforum/index.php?topic=1179.msg10220#msg10220

Frankenford did reference a stud and nut for attaching since there was not enough room for a bolt.

I bought the Hayden 2711 for mine about 2 months ago from Rock Auto with the thought of using a fan I had already. Turns out the fan is too large a diameter for the factory shroud, so I will be buying an 18"  version, Derale 17118, of the fan you listed from Summit. Wasn't till today I realized that both have the a dual bolt pattern for the clutch, or I would have went with the Hayden 2765.

Took a minute to figure out how to correct the chart to be readable.

Last edited by Bolted to Floor (2/26/2018 12:16 PM)


John  -- 67 Mustang Coupe 390 5 speed
 

2/26/2018 12:12 PM  #8


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Bolted to Floor wrote:

I was doing some digging for the same thing on my car and stumbled across another part number that is shorter than  a Hayden 2711 on another site. I made a spread sheet to compare. Its Hayden 2765. Your Derale fan has a dual bolt pattern that will mate up to this clutch.
 Hayden 2765Hayden 2711Hayden 2710Bolt Quantity444Bolt Thread5/16-18 Hole5/16-18 Hole5/16-18 HoleClutch TypeB - Non-Thermal and Std ThermalB - Non-Thermal and Std ThermalB - Non-Thermal and Std ThermalColorRaw Aluminum in ColorRaw Aluminum in ColorRaw Aluminum in ColorDescriptionFan ClutchesFan ClutchesFan ClutchesDrawing TypeBBBDuty RatingStandardStandardStandardElectronic Clutch?Non ElectronicNon ElectronicNon ElectronicFan Bolt Circle IN3.2533Fan Mount Dia. IN2.622.372.37Fan Mount Height IN1.093751.41.75MaterialAluminumAluminumAluminumMeets / Exceeds OEM?YesYesYesMount Dia. IN2.322.332.33Mount Hole Qty444Mount TypeFlangeFlangeFlangeMounting Hardware?Not IncludedNot IncludedNot IncludedNew or RemanNewNewNewO.E. Replacement?YesYesYesOverall Dia. IN7.27.27.2Overall Height IN2.6718752.9843753.296875Performance Rated?YesYesYesPilot Depth IN0.560.750.75Pilot Dia. IN0.75.63 to .75.63 to .75RotationStdStdStdStyleSTANDARD DUTYSTANDARD DUTYSTANDARD DUTYTypeThermalThermalThermalWire GuageUses Original Equipment ConnectorUses Original Equipment ConnectorUses Original Equipment ConnectorWire QuantityUses Original Equipment ConnectorUses Original Equipment ConnectorUses Original Equipment ConnectorSource
http://fepower.net/simplemachinesforum/index.php?topic=1179.msg10220#msg10220

Frankenford did reference a stud and nut for attaching since there was not enough room for a bolt.

I bought the Hayden 2711 for mine about 2 months ago from Rock Auto with the thought of using a fan I had already. Turns out the fan is too large a diameter for the factory shroud, so I will be buying an 18"  version, Derale 17118, of the fan you listed from Summit. Wasn't till today I realized that both have the a dual bolt pattern for the clutch, or I would have went with the Hayden 2765.

That Hayden 2765 looks similar but it has a 3.25 bolt circle for the flange that mounts to the water pump, whereas the ford water pump has a 3" bolt circle.  Be careful about the fan - as far as I can tell the shrouds are made for a 17" fan and my shroud and 17" fan had about 1/2" clearance all around.
 


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2/26/2018 12:22 PM  #9


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

jkordzi wrote:

That Hayden 2765 looks similar but it has a 3.25 bolt circle for the flange that mounts to the water pump, whereas the ford water pump has a 3" bolt circle.  Be careful about the fan - as far as I can tell the shrouds are made for a 17" fan and my shroud and 17" fan had about 1/2" clearance all around.
 

The 3.25 pattern is for the fan to clutch pattern not the water pump.

I don't mean to confuse applications, but mine is on a 67 with a 390 and a 24"wide radiator and a factory shroud. The original fan diameter was 18.25 inches.  
 


John  -- 67 Mustang Coupe 390 5 speed
 

2/26/2018 12:53 PM  #10


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

Yeah you're right - don't know what I was thinking.


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2/26/2018 9:56 PM  #11


Re: Fan shroud on aluminum radiator with fan clutch for 65/66 Mustangs

I noticed no air conditioner compressor was mentioned. If equipped with one, be sure the shorter clutch doesn’t put the fan blades into the compressor pulley. I think this is more of an issue if using a Sanden compressor with a double groove a/c clutch.

Glad you found the shorter fan clutch and the better quality shroud. Looks like a great solution.


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