Lady72nRob71

I want to know how your thermal clutch is working, as in the following ways… -When you start up cold, how long does it take until the clutch disengages? At waht RPM will it disengage?

-At idle, when engine is only partially warmed up, it is engaged?
-Have you heard it cycle on and off when the engine is hot and idling?
-When does it disengage when you bring up the RPMs?
-Do you hear the fan roaring and or belt squealing upon hard acceleration from slow speeds?
-Does it disengage quickly when RPMs are raised?

I want to know because my new 2747 heavy duty clutch seems engaged MOST of the time.
It is always engaged at idle or below 1000RPM, any temperature. It does not cycle on or off.
Upon acceleration, it is noisy and will not disengage for about 10 seconds, robbing HP.
This is on my 72 350 with AC and 2.25" pitch fan.

I want to know if this is the behavior of the Hayden heavy duty clutch or if maybe mine is bad.
It has about 250 miles on it so it should be "broke in" by now.
If this seems normal I am going to try the standard model.
If it seems bad I will contact the MFR.

The original clutch on my '86 works great. It disengages within 5 seconds from a cold start and will not engage until it is hot. It engages and disengages when hot. Upon acceleration, it disengages in a couple seconds or less. This I like. This is on the 307 with AC and 2" pitch fan.

Thanks!

1971 442 convert

I changed to the 2747 last October.

Mine seems engaged all the time as well.
Have about 200 miles on it in mostly cooler weather.
So far I have noticed an improvement with the temp but
have not had enough hot weather to really test it.

Mine is not noisy and I hear no roar.
I do notice that it is moving a ton more air than my previous set up.
Car is running around 180 and it used to heat up as I slowed down or sat at lights etc. Now it seems to drop below 180 as I slow down.

Sorry I do not have much experience with clutch fans and only learned of this one through some good guys helping me here on this site.

Roger

brown7373

Mine has been installed almost a year and 5 or 6000 miles. It is engaged most of the time and as Roger said, it moves a lot of air. My engine runs at 180 degrees almost all the time. In heavy traffic A/C on in Florida, maybe it'll reach 190, but comes down as soon as trafic moves. My car is a cruiser and I don't care about tenths, but I was wondering how much it might effect gas mileage with it engaged most of the time.

Lady72nRob71

Interesting trend...
Looks like I will get a std version to see if that helps. OR maybe I will swap the one on the 86 into the 72!

I wonder if the AC delco ones are any better...

BILL DEMMER

i like the acdelco clutch i put on ernie. it's a split between the std. hayden, and the hvy. duty hayden. the big plus is, it hasn't started leaking like the hayden's i've used previously(after a couple of years). the application for the acdelco ,that is still going strong, is for a b/c body wagon with 307 from the 80's. it roars pretty good for a couple of minutes on cold start-up(7 blade fan), then gets quiet as a mouse. get ernie hot, and you're gonna move a bunch of air for a minute or so, until it cools down. the acdelco number is 15-4216. it's a disco'd part number, but, i know where they can be purchased reasonably.


bill

Lady72nRob71

You got one for me?

BILL DEMMER

yup!
pm if interested.


bill

1BOSS83

My 2747 is engaged most of the time. 180 flat and even during a humid 90 degree day it'll sit there and idle at it. No roar and makes the same noise as the stock set up but moves a significant amount of air. I cannot speak to the AC delco version but this HD clutch one the best 50 dollars I've ever spent.

1971 442 convert

Hey Rob did you ever get this clutch fan thing figured out?
I am still not sure mine is working properly as I discussed in my earlier post.
I can not sit very long without the temp going up so I am thinking about trying another one maybe the standard one.

brown7373

I got tired of the constant roar when I accelerated and I changed back to the correct original clutch for an A/C car. Yeah, my temperature might rise a little bit more than the almost constant 180, but since the engine is designed to run at 200, maybe thinking it is better at 180 is not necessary. Like a lot of guys, I like to see the temperature stay low and stay constant. But I think we have been convinced that lower is better. Actually, running at the correct operating temperature is better, for mileage, emissions and keeping the oil free from moisture. Now may car runs closer to 185, might creep up to 195 in traffic, but drops down below 190 when I get moving again.

1971 442 convert

My car runs at 195 to 200 on the highway but thats not the problem its stopping for any length of time it just climbs and will boil over if I don't just shut it off.

I was going into a large show Show this weekend and I had to shut it off probably 10 times as it was a 45 minute wait. As it was I was right over the top on the temp gauge as I parked.

Lady72nRob71

Yes, it is all figured out.
It sounds like your clutch is not even engaging when it should. Do you hear any roaring sound when hot?
The HD version stays engaged more than I wanted it (by design that is how it is supposed to be) to so I went with the original Delco part# listed by Bill.
It is similar to Haydens 'standard' part.
Even with that Delco clutch, Lady never breaks a sweat.

Make sure you have a shroud and I assume you do, as missing ones are often overlooked.

1971 442 convert

No Roar that I hear and yes I have a shroud with the Hayden 2747 clutch and Hayden 3619 fan blade. Also have the Spectra Premium CU165 Heavy Duty Rad.

I may research and get the Delco clutch to see if it makes any difference.

Thanks Rob