Thermal vs. Torque Drive fan clutches, which is better?

[WH23G3G]

When I took apart my 400 initially it had a torque drive desgin fan clutch on it, not sure if it is OEM or not. The only numbers or markings on it are 17050561. When I rebuilt it I installed a parts store available thermal fan clutch listed by application for 73 Charger 400. Which type would've come on a 73 Charger with a 400-4BBL and A/C originally? I show a part number but not sure how they list these in the 1973 Chrysler parts catalog. It says part #3462179 w/ 318,340,360,400, 440 eng. w/A Cond. w/2.94/3.23/ axle 7 1/4" dia. Then there is another part #3462174 w/318, 360, 400, 440 eng. w/A cond. w/2.71/2.76 and 2.94 Axle 6" dia. Under fan clutch those are the only two numbers that apply to Chargers/Coronets/Satellites with big blocks w/A conditioning. Mine was originally a 318, so I don't know how I would choose based on axle ratio since an 8.75 3.91 limited slip was added. I'm not sure what the 6" and 7 1/4" diameter is referring to either. What's a high quality brand of fan clutch that works good?

[cdr]

hayden makes a good one,you want the larger one 7 1/4 thermo

[maybrfd]

Don't know how you are using your car, so the experience may or may not apply.  We race cars hat see often see above the 5000 RMP range.  We tried many different clutch fans, and there are some good ones on the market.  However, no matter what we used they eventually gave up the ghost seeing the higher R's.  There are advantages and disadvantages to the various makes and models of fans, but we choose the flex fans over the clutch fans for our applications.  They seem to do a good job on the street as well as at the track, and we haven't replaced one yet.  Hope this helps.

[WH23G3G]

Someone else was explaining to me how the two work thermo and torque drive. They said the torque drive is always running but the thermo comes on at a pre-determined temperature. I've got to change it out anyway and the water pump that I also have on the motor was a reman Cardone water pump when I built the motor but I'm not sure how good its flowing, it had been sitting for awhile before I had ever started building the motor. I'm going to go ahead and change it out too. Is there any advantage of putting a high volume pump on and does it matter if it's iron or aluminum?

[cdr]

Don't know how you are using your car, so the experience may or may not apply.  We race cars hat see often see above the 5000 RMP range.  We tried many different clutch fans, and there are some good ones on the market.  However, no matter what we used they eventually gave up the ghost seeing the higher R's.  There are advantages and disadvantages to the various makes and models of fans, but we choose the flex fans over the clutch fans for our applications.  They seem to do a good job on the street as well as at the track, and we haven't replaced one yet.  Hope this helps.

they also draw more horse power ,this car sounds like its a street car,been running the same fan clutch on our 10.90 car for 15 years,still works but thats just my  not disagreeing with anyone

[A383Wing]

I run non-thermal clutch fans on all my Chargers....as opposed to the thermal style with the little spring in front.

non-thermal ones will draw more air through radiator at lower speeds and disengage at higher RPM where as the thermal styles with the little springs in front will engage when radiator temp climbs high enough to make it work. (which in my opinion, it's already too hot)

I'm running one on the Daytona, and you know how small the openings are in the front, no cooling issues since I put it on

Bryan  (not sure if I explained it right)

[WH23G3G]

I swapped out the fan clutch I had on today. The one I had on there was probably a little over a full inch shorter in diameter than the one I crossed referenced from the 73 Chyrsler parts catalog. The one I took off also said Made in China and the one I got today says Made in USA. It's a Torqflo brand. I'm also going to through another water pump on while I've got it off. Should I go high volume, iron, or aluminum?

[A383Wing]

I have never had any problems with the stock iron pumps...but I'm sure other people will say something different

Bryan

[WH23G3G]

I put on a reman Cardone water pump that I had sitting on my garage shelf probably for a year or two before I even started rebuilding my motor. So it's quality now maybe questionable. It may be working fine or may not. I didn't check it but at least I know it's not leaking. If adding a higher performance water pump could possibly increase the reliability of the cooling system and the engine as a whole I don't mind getting another one for a few more extra dollars. I'll also throw in a new high-flow thermostat to be matched with the high volume water pump. I was just wondering will a high-volume water pump blow my hoses out or increase pressure beyond the 16 PSI cap?

[Fred]

It only increases the water flow. (not the pressure)

[WH23G3G]

I'm going to order a high-flow water pump for sure then. I also wanted to know if I originally had my fan installed wrong. I think I had it on right but when I showed it to several shops that I know today I was told I had it installed wrong. I'm using the 20" 7 Blade Aluminum A/C Fan Blade part #3462149. How can I be sure that I install the fan facing the correct way, there's no markings on it saying Engine Side.

[A383Wing]

not sure if you can tell by this pic or not

Bryan

[WH23G3G]

Is that the same fan as the A/C fan? I had some mechanics at shops look at it, some of them really weren't sure either. I'd hate to put back on wrong and have it overheat again if that was the cause, everything else was in working order. I never did the paper test though on the radiator. I'm just trying to save the trouble of doing it twice. I didn't take the shroud off to try and save time so I'm sure it will be harder to get it back in. I'm going to try and take it to a guy who I know restores Mopars tomorrow and see what he says. 

[A383Wing]

It's a Mopar fan blade and it has 7 blades....it's just one I had laying around and it works perfect on the Daytona....you just need to make sure it's bringing air in through the radiator by having it on correctly.

my test for the fan is by using a shop rag, not a piece of paper

Bryan

[WH23G3G]

Ok I checked with a shop that restores Mopars and verified the correct way my fan blade mounts. All along I had it right. The only issue I know that could've contributed to the overheating issue for sure was the timing was most of it and maybe the smaller diameter fan clutch. So while I've got access to the crank pulley nut at least a little bit, I'm going to redo the ignition timing by putting the piston at TDC and reinstalling the distibutor. So I had to remove the fan and fan clutch. So I've got a larger diameter fan clutch by about 1.5 inches, I went with a Mr. Gasket 180 high flow thermostat, and chose the Milodon High Volume Aluminum water pump. Hopefully with these items and the timing correctly set after the last guy messed it up, the car won't overheat. Hey how much coolant will I lose if I just change the water pump out without draining any? Since it has a separate water pump housing that I won't remove.   

[A383Wing]

if you pull the pump. yer gonna loose about 2 gallons or a little less

Bryan

[WH23G3G]

Update on my progress. I got the Milodon High Flow Aluminum water pump from Summit and finally got it put on. There wasn't much difference in weight but the only difference I saw is there was a plate welded onto the impellers. Not sure what it does. It also said GMB Japan on the housing. I guess it was made in Japan. I also reinstalled the fan correctly, it in fact was on the correct orientation the whole time. Maybe the timing or the fan clutch was too small. I also added the Made in USA Torqflo thermal fan clutch that crossed over from the 73 parts catalog part #3462179 which is for 318,340,360,400, and 440 with A/C and 2.94/3.23 axles 7.25 diameter. And this new fan clutch is right about 7.25 in diameter whereas the one I removed was right at 6 inches. I also noticed this new fan clutch is just a little taller. Does that make a difference? I still have to install the thermostat. I got a high flow Mr. Gasket 180 that I'm waiting to put in but realized didn't have a gasket. Is there a high performance gasket because it's kinda of a pain to get to with the A/C compessor on?