The jaguar based fan clutch just isn't cutting it in stop and go traffic on the Belvedere with the 440.

Cools fine at speed and the rest of the system is all new/rebuilt so no issues there.

Short of trying the repro one Tony's parts has who here runs a fixed fan? Opinions?

Do a search for the Mercedes fan that feets posted.

what is the pump pulley ratio? How many blades on the fan? 6 or 8 vanes on the pump? shroud? fan distance into the shroud? If its locking up when hot I wouldn't think it'd be that (fan clutch)

No idea on the pulley ratio.

Running an 18" 7 blade Mopar fan with the jag clutch.

Tried the 6 vane pump and just because the milodon one with the anticavitation plate.

Running the shroud built for the rad by Wizard cooling.

Fan's halfway into the shroud maybe a bit more.

From reading up on the clutches the Jag clutch only comes in standard duty as per Hayden. Standard mean no hot idle lock up feature so it'll never truly roar when hot.

Running a 180 T-stat and it'll hold that no issues when staying around 30-40mph and up. The clutch just doesn't pull very hard. Fire it up in the driveway it will idle for 20mins plus never gets hot. Go a few blocks and get it up to 180 for a bit and then try and idle and it will start to creep. 205-210 never tried to see how bad it will get.

Get an IR temperature gun and give us numbers.

Is there a 20+ degree temperature drop between the upper hose and lower hose?
Are there hot spots on the radiator?

The basic symptoms lean towards an inadequate lockup of the fan clutch but it's all speculation until you get facts to work with.

Get numbers and get back with us.

My built 440 with a never touched 65 C body rad and shroud and stainless flex fan runs 180 or so all day.My kids 62 413 no shroud but recored OE rad runs the same.Even in the 90s it never gets over 190 degrees.Rocky

Anyone know of a trick to 'tune' the lockup of a fan clutch? Maybe by altering the bi-metal spring on the front?

I also have a (fairly new) fan clutch that doesn't seem to lock up when hot. Not even at 220+.
In fact, I even think the fan has more drag when cold than when hot, but that could just be the grease inside thinning out with heat.

I used a Superbird/Daytona seven blade fixed fan on my '62 440 cu in convertible for a while. It worked OK at idle speed in traffic but it sounded like a gigantic Hoover vacumn cleaner at higher rpm. I'm using the Jaguar clutch now and it seems to work fine. I'm using a FlowKooler hi-volume water pump.

Robert, do you have a recommendation for a solid fan? My 440 runs a little hot at idle too in bumper-to-bumper traffic and I would mind spending a little cash for a test. I think I can fit a Flex-a-lite 1619 in my shroud with the right spacer but I would rather get a solid fan that others have used and like.

Steve I would suggest a JY solid steel OE fan with as many blades as you can find & space it ~2/3 into the shroud. You might wanna go to a smaller dia pump pulley to speed up the fan (air) flow and the water flow

I would think that you could adjust the temperature at which the bimetalic spiral locks up the clutch by moving the attachment point of the center of the spiral.
Twist the center attachment point forward, or add a spacer that creates more tension in the spiral to lock up at a lower temperaure.

To get the fan blades to rotate closer to engine shaft rpm, replace the silicone fluid inside the clutch with a fluid of higher viscosity.

Silicone is used because it is fire resistant.

Perhaps high viscosity silicone grease could be mixed into the original silicone fluid fill until you got the lesser amount of slip you desire.

http://www.amazon.com/Jet-Lube-Silicone-...=silicone+fluid

A clutch manufacturer like Hayden might be able to supply you with replacement silicone fluid of various viscosities, rather than a complete new clutch assembly.

http://www.haydenauto.com/Hayden%20Custo...rm/Content.aspx

http://www.haydenauto.com/online%20catalogs-ecatalog/content.aspx

A solid 9 blade fan with the right spacer might be the simplest first thing to try.

360view,

I did try exactly that today, trying to modify the Thermo spring anchorpoint.
But when I lifted the end of the spring out of the little bracket, the entire spring could be rotated easily, so I think the thermo lockup mechanism has never worked at all in this clutch.
No matter in what position I put or held the thermo spring, the drag on the clutch remained exactly the same.

In the mean time I will do some more Googling on getting the low down on the interal workings of it.

I would love to find a heavy duty clutch to keep that viscous fan spinning more at idle. Until then, I am going to test a 7-blade solid fan with spacer on Saturday.

RIGHT before I do that, I will drive for about 10 minutes then at idle point my laser therm at the radiator, lower and upper hose and the heads and make note of the temps. After the swap, I will drive another 10 miles then idle and repeat the tests and document the differences. I'll create a new thread and post my results in case others are interested in the differences between a Mopar Performance viscous kit and a seven blade solid on a mildly built 440.

Really didn't want to hijack this thread so I'll start a new one when I start my experiment this weekend.

If it is of any help,
here are the 1992+ Magnum engine fan
Chrysler part numbers from about ten years ago.

7 bladed fan
Chrysler PN 52027999

or the 9 blade fan
(PN 52028440 )

These may be too large for your shroud,
as the diameter of my 5 bladed 1995 Magnum fan is about 21.5 inches

Running down the highway temp rides right at 180 or just a touch lower which seems normal/good as my t-stat is a 180 unit.

As far as the lock up of the fan at idle I have my doubts on the Jag based clutch as it lists as standard duty. From reading I found this on allpar

"There are light-duty and heavy-duty fan clutches, and within those categories they differ in such things as temperature setpoint and presence or absence of an idle-lock feature.

The idle-lock feature, usually found only in heavy-duty clutches, drives the fan whenever the engine is at idle or low speed. Without the idle-lock feature, the clutch is purely thermostatic. If the air coming off the radiator isn’t hot enough to make the clutch engage, the fan will not be driven. In situations calling for assured airflow at idle and low speed (such as a car with air conditioning, or low-speed/stuck-in-traffic driving), the idle-lock feature is good to have."

PosessedDuster, I'm with you my friend.

I have the parts in hand and if I can get some time tonight I plan to put the solid fan and spacer in my Cuda and I can tell you how it affects my temp.

At idle, I was only seeing a 5-10 degree difference between the upper and lower hoses. This tells me that clutch is not locking up enough to put adequate air through my brand new 26" 3 tube radiator.

Here's something that may be helpful. It's a link to the Hayden website that explains the difference between the various types of fan clutches. Thermal vs. Non-thermal. Standard duty vs heavy duty vs severe duty: http://www.haydenauto.com/upload/HaydenA..._TS_6980012.pdf

For those of us with '62 - '65 B bodies we don't have much to choose from as the Hayden 2765 is the only one short enough to fit. Other Mopars with more clearance may have more choices.

Here's a link to the Hayden catalog that includes all the dimensions of the various clutches:

http://www.haydenauto.com/upload/HaydenAuto/Documents/Cat_Hayden/2013_HaydenCatalog_FINAL.pdf