Hello, My fan clutch turns loose at hot of cold temps. It dosn't over heat but i would like to have it run more cool. I am thinking about putting a replacement thermo cluth or a direct drive. I can get a cluth from summit but where do you get a direct drive that you can bolt your original fan too? I am not interested in originalaty for the fan. Thanks in advance. Eric
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Re: 72 Fan clutch direct drive?
Running the OEM fan direct drive will make a lot of unpleasant noise above 3000 to 3500 revs and probably cost you 10 to 15 HP at the top end. I'd suggest buying a proper viscous fan clutch, if you really think it is bad.
The original thermostat is 195 degrees, so it shouldn't run less than this and might run hotter in warm weather and low speeds.
You can cool things down at idle and low speed by back-specing the ignition curve to the equivalent pre emission engine , say 1965, which would include the appropriate '65 vacuum can with full manifold vacuum and disabling the TCS if equipped. The '72 ignition curve was intentionally set up to be retarded from optimum in order to increase EGT for emissions and this throws a lot of extra heat into the cooling system.
Duke -
Re: 72 Fan clutch direct drive?
Running the OEM fan direct drive will make a lot of unpleasant noise above 3000 to 3500 revs and probably cost you 10 to 15 HP at the top end. I'd suggest buying a proper viscous fan clutch, if you really think it is bad.
The original thermostat is 195 degrees, so it shouldn't run less than this and might run hotter in warm weather and low speeds.
You can cool things down at idle and low speed by back-specing the ignition curve to the equivalent pre emission engine , say 1965, which would include the appropriate '65 vacuum can with full manifold vacuum and disabling the TCS if equipped. The '72 ignition curve was intentionally set up to be retarded from optimum in order to increase EGT for emissions and this throws a lot of extra heat into the cooling system.
DukeComment
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Re: 72 Fan clutch direct drive?
If you really must have a direct drive, Long Island Corvette Supply sells themComment
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Re: 72 Fan clutch direct drive?
If you really must have a direct drive, Long Island Corvette Supply sells themComment
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Re: 72 Fan clutch direct drive?
The noise is, how shall I describe it...ya' ever been behind a turbofan engine at ground idle? It's a lot like that. It's not a noise you can get used to.Comment
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Re: 72 Fan clutch direct drive?
The noise is, how shall I describe it...ya' ever been behind a turbofan engine at ground idle? It's a lot like that. It's not a noise you can get used to.Comment
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Re: 72 Fan clutch direct drive?
Eric-----
I DO NOT RECOMMEND direct drive OR, in case the thought occurs to you, a flex fan for a Corvette. Purchase a heavy duty THERMAL fan clutch. My recommendation is a GM #12529342. This unit will be a direct bolt-on in your application and will absolutely solve your cooling problems IF, AND ONLY IF, your cooling problems are ACTUALLY related to some inadequacy in your fan drive.
Incidentally, the GM list price for the above-referenced unit has recently been reduced substantially. Currently, the piece lists for $99.73 and can be purchased for about $60 at discount.In Appreciation of John HinckleyComment
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Re: 72 Fan clutch direct drive?
Eric-----
I DO NOT RECOMMEND direct drive OR, in case the thought occurs to you, a flex fan for a Corvette. Purchase a heavy duty THERMAL fan clutch. My recommendation is a GM #12529342. This unit will be a direct bolt-on in your application and will absolutely solve your cooling problems IF, AND ONLY IF, your cooling problems are ACTUALLY related to some inadequacy in your fan drive.
Incidentally, the GM list price for the above-referenced unit has recently been reduced substantially. Currently, the piece lists for $99.73 and can be purchased for about $60 at discount.In Appreciation of John HinckleyComment
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