Thermo Clutch Fan vs a Non-clutch fan
08-12-2011, 02:12 PM
#21
Drifting
When you first start the engine the silicone fluid inside the clutch is cold and the fan turns fast,as the fan turns it heats up and thins the fluid and the clutch will disengage and then the thermostatic spring takes over and controls the fan speed.
I can't think of reason the clutch won't fit your 75 other than the zones puters are wrong.
I can't think of reason the clutch won't fit your 75 other than the zones puters are wrong.
08-12-2011, 02:37 PM
#22
Race Director
To be honest I try to use it on everything even if I have to change the water pump to the later large bearing style. I also install the largest diameter 7 blade fan that the fan shroud will accept.
08-12-2011, 02:50 PM
#23
Melting Slicks
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St. Jude Donor '12
Its listed for severe duty and most Corvettes probably come under heavy duty I believe. I think cars like Suburbans with AC are severe duty. The 78 Corvette L82 with AC uses this clutch from the factory.
To be honest I try to use it on everything even if I have to change the water pump to the later large bearing style. I also install the largest diameter 7 blade fan that the fan shroud will accept.
To be honest I try to use it on everything even if I have to change the water pump to the later large bearing style. I also install the largest diameter 7 blade fan that the fan shroud will accept.
08-12-2011, 03:20 PM
#24
Race Director
Here is a thread talking about the 2799,do a search of ajrothm , and see the kind of hp he is running through this fan clutch.
http://forums.corvetteforum.com/c3-t...an-clutch.html
Also in this thread are the old original numbers for this severe duty clutch and also a very old thread with lots of discussion about the clutch.
08-12-2011, 09:54 PM
#25
Melting Slicks
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St. Jude Donor '12
I just took my fan off to check what the PO placed on there. It is a Hayden #2741 heavy duty. Should I replace it with the Hayden #2799 severe duty? What are your thoughts?
08-12-2011, 10:05 PM
#27
Melting Slicks
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St. Jude Donor '12
It's pretty much new. Has about 500-800 miles on it. Engine runs fine 180-195. I was just thinking that the severe would help the A/C keep cooler at idle then the heavy duty. I do not know if they both pull the same amount of air or not.
08-12-2011, 10:13 PM
#28
Race Director
Go back and look at the Hayden link I posted. Hayden says they both pull the same but the SD will stay cooler and last longer, if the drive is fluid seems like cooler could pull stronger. Look down the page where it describes the HD and SD and talks about 70% working area.
08-12-2011, 10:28 PM
#29
Melting Slicks
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St. Jude Donor '12
I saw that part 26.6 vs. 70 area. So in theory the SD should stay cooler longer then the HD due to the larger surface area that keeps it cool. SOOOO the SD should stay engaged longer. Are the thermostatic springs engaged at the same temp. of 170?
08-13-2011, 09:06 AM
#31
Race Director
Just a guess but I would say yes. There was somewhere a complete set of specs on all their clutches ,if I get a min I'll see if I can find it,it should show.
08-13-2011, 09:08 AM
#32
Race Director
08-13-2011, 09:38 AM
#33
Melting Slicks
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St. Jude Donor '12
I found thier spec's by chance the other day. Funny thier spec's have a slightly different % on how the fan turns on each unit. Not much of a difference. If I remember correctly the HD was 70-90% compared to SD 80-90%. Again going on recall here, I only seen one temp, for the spring to engage though.
Last edited by daanbc; 08-13-2011 at 09:42 AM.
