Fan clutch question

[Jeffrey S.]

Hope you all had a good Thanksgiving! Here's what I've got- I had the original fan clutch from my '69 (Schwitzer) rebuilt several years ago by one of the advertisers in the Driveline. After the re-build itt was always very tight and I believe that it was always engaged. After reading some posts here and re-reading an article on rebuilding these in the Restorer, I decided to see if perhaps there was too much oil or silicone fluid in the reservoir. It was suggested in the article that overfilling would keep the clutch engaged full time. I removed the bi-metal strip and tried to get the "plug" out but it wouldn't. The center pin did come out so I inverted the unit over a jar and left it over night. About 1/2 a teaspoon came out and now it is much freer. It feels more like the GM replacement that I put on. The questions are: by removing and re installing the pin did I damage the unit? By removing this amount of fluid did I make the unit non-functioning? There is suppose to be around 1 oz. of silicone fluid in there. Any help is appreciated.
Jeff

[John S.]

Re: Fan clutch question

Jeff
can only give you my experience. I added the silicone fluid to my original 67 Swirster clutch and it worked fine except that it would engage right at about 180-185 F. Definite difference in noise generated at about 2500-3000 rpm. It would not disengage over a certain rpm either. I played with the amount of fluid for about a year and gave up. I had to send the fan clutch in the 65 out for rebuild so I threw this one in also. They are both on their wy back now. I will post results when I get them in and tet run.

[Jeffrey S.]

Re: Fan clutch question

John,
Thanks for sharing your experience with your fan clutch. Today the temp here in Detroit was almost 60 so I put the original fan clutch back on having removed about a half teaspoon of silicone the other day. When I spun the fan it was much freer. I took the car out and let it warm up good. It seemed to operate properly with no noise. After shut down the fan spun for about 1 revolution which is much more than before but not as much as the GM replacement Eaton fan I removed. Of course, it remains to be seen what will happen next July when the temp is 90 and the A/C is running. That will have to wait for 7 more months.
Jeff

[Alan S.]

Re: Fan clutch question

Hi Jeff,
It sounds like perhaps you're on the right track.
How much had the engine cooled off when you did your test?
If it still had some heat in it perhaps that caused the clutch to not let the fan blades spin as many turns as is typically described for cold clutches.
Happy Winter!!!!
Regards,
Alan

[Jeffrey S.]

Re: Fan clutch question

Alan,
The engine was just at operating temp. The temp guage showed about 190 degrees which is as it always is. The outside temp was only about 60 so not very hot. The fan rotated about 1 full turn which, as I understand it, is not as free as it should be. I am more concerned about how well it hooks up when it is really hot. That won't be tested until next summer.
Jeff

[Joe L.]

Re: Fan clutch question

Alan,
The engine was just at operating temp. The temp guage showed about 190 degrees which is as it always is. The outside temp was only about 60 so not very hot. The fan rotated about 1 full turn which, as I understand it, is not as free as it should be. I am more concerned about how well it hooks up when it is really hot. That won't be tested until next summer.
Jeff

Jeff------


My guess would be that this clutch is going to be "engaged" MORE (i.e. at a lower temperature) than it would if it were at original spec. If so, it would cool better than original but it would result in the fan being a bit more noisy (the more air it draws, the noisier) and there would be a slightly greater horsepower draw (the whole purpose of a fan clutch over a direct drive fan is to reduce noise and horsepower draw when cooling needs are lower).

[Jeffrey S.]

Re: Fan clutch question

Joe,
Thanks for your input. I can live with the existing noise level as long as it cools well in the heat of summer. I think the next step is to drain off another 1/2 teaspoon and see if it gets freer.
Jeff