Fan Clutch

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Nov 18, 2006 | 09:53 AM

bbvette69

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From: London

Fan Clutch

My Corvette is a 69 427-390p and i have a fan clutch with a rectangular band on the front saying "this side up",is this an original part? It seems that the new ones have a spiral spring on the front.

Nov 18, 2006 | 02:01 PM

RIJVETTES

Burning Brakes

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From: San Diego California

I just received my new clutch from Midamerica for my L48 with AC. Its suppose to be a GM product. Its got the spiral spring. Don't know if this helps. Good luck with your install. Jim

Nov 18, 2006 | 07:14 PM

70Donnybrooke

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From: Mertztown Pa

Quote:

Originally Posted by bbvette69

My Corvette is a 69 427-390p and i have a fan clutch with a rectangular band on the front saying "this side up",is this an original part? It seems that the new ones have a spiral spring on the front.

If I can recall correctly my 70 350/300 auto with the big block rad in it has what you describe. I thought is though that is said "this side front".

Nov 18, 2006 | 11:26 PM

bondoboy

Burning Brakes

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From: Huntingburg Indiana

I believe the clutches with the coil are "thermal." They kick in when the temp rises. I believe the others slip at a certain rpm. Correct me if I'm wrong. My 71 had the non-thermal type on it.

Nov 18, 2006 | 11:53 PM

hwcoop

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From: Airdrie Alberta

Off of a 73 L82

Nov 19, 2006 | 03:53 AM

bbvette69

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From: London

Thanks for the info and pics.I cleaned clutch and found a code on the rim where it attaches to the water pump 2 13 69 SC.If its the date code is that Feb 13 1969?

Nov 20, 2006 | 11:56 AM

RPOL68

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From: Sacramento CA

That is a good date code and that is the correct design for the '69 BB. Thermal spring came along later.

Nov 20, 2006 | 07:35 PM

Hammerhead Fred

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From: Midlothian VA

Quote:

Originally Posted by bbvette69

My Corvette is a 69 427-390p and i have a fan clutch with a rectangular band on the front saying "this side up",is this an original part? It seems that the new ones have a spiral spring on the front.

It says "this side up" because it's a bi-metal strip which, when heated, is designed to bow in one direction. Underneath it you'll find a little pin that the bi-metal strip presses against depending upon how hot the bi-metal strip gets.

The coil/spiral spring is also bi-metal and that spring and performs the same function expanding and contracting depending upon how hot it is. Works just like the choke spring if you have a manual choke.

Don't know about the 69 but on my 71s -72 BB & SM's they all have the same bi-metal strip.