Viscous clutch fan for SBC 350 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BlouDon · 10-05-2020, 12:39 PM

Out here in South Africa we have to improvise....

I'm, one of those who believe that I would rather have a fan with 300HP driving it than a 0.33HP electrical motor.

The flex blade fans also does not appeal to me, so I went with a viscous coupling as found on older Jag XJ6 and XJ12 engines...

I have a 74ºC (165ºF) thermostat fitted and with normal driving, temp never goes above 80ºC (176ºF). In traffic, with AC on, I now and then see temp creeping up to 90ºF (194ºF) but that is when the clutch engages and then the temp drops rapidly back to below 80ºC (176ºF)

**truckster** · 10-05-2020, 01:28 PM

It looks like you've crafted it well.

**The Rocknrod** · 10-05-2020, 01:55 PM

That found shroud looks more like an actual shroud than any I've seen lately.

BlouDon · 10-05-2020, 02:17 PM

Quote:

Originally Posted by The Rocknrod

That found shroud looks more like an actual shroud than any I've seen lately.

Thanks! The design is mine, but not the welding! Tried to keep the gap between fan tips and shroud as small as I dare.

But I find the viscous clutch rarely engages. The "disengaged" amount of fan rotation is already enough to provide significant air flow.

Dead Parrot · 10-06-2020, 10:48 AM

Looks good. If you have any pics of the shroud before installation, might post those up as well. And maybe some pics of that AC compressor bracket. Might be useful to folks wanting to add an aftermarket AC to a truck.

Your results with the clutch are similar to mine. I run a standard duty clutch and it provides plenty of spin to the fan to keep things cool without sounding like a jet engine under the hood. The heavy duty version ran things too fast when the cooling just wasn't needed. Running a 195F thermostat here.

BlouDon · 10-06-2020, 11:36 AM

I don't have pics but I do have these drawings (all dimensions in mm), that may help. No guarantees of course.

As for the AC bracket, I used this:
https://www.summitracing.com/int/par...make/chevrolet

BlouDon · 10-06-2020, 12:09 PM

But then I thought, its only 4 countersunk cap screws and 2 x 10mm bolts to remove the cowling so I removed it quickly, a 5 min job....

BlouDon · 10-06-2020, 12:10 PM

Pictures are worth a 1000 words right?

10-05-2020, 12:39 PM	#1
BlouDon Registered User Join Date: Feb 2019 Location: Centurion, Gauteng, South Africa Posts: 227	Viscous clutch fan for SBC 350 Out here in South Africa we have to improvise.... I'm, one of those who believe that I would rather have a fan with 300HP driving it than a 0.33HP electrical motor. The flex blade fans also does not appeal to me, so I went with a viscous coupling as found on older Jag XJ6 and XJ12 engines... I have a 74ºC (165ºF) thermostat fitted and with normal driving, temp never goes above 80ºC (176ºF). In traffic, with AC on, I now and then see temp creeping up to 90ºF (194ºF) but that is when the clutch engages and then the temp drops rapidly back to below 80ºC (176ºF) Attached Images __________________ Best regards, Philip Chev: '70 C10 (350 V8 / 700R4 ) & '59 Apache ( 235, 3-sp ) Jensen Interceptor '74: Mopar 440(EFI'ed) / 4L60e Jaguar: '72 E-type Coupe V12 & '74 E-type V12 Convertible & '80 XJS V12

10-05-2020, 01:28 PM	#2
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,791	Re: Viscous clutch fan for SBC 350 It looks like you've crafted it well. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

10-05-2020, 01:55 PM	#3
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Viscous clutch fan for SBC 350 That found shroud looks more like an actual shroud than any I've seen lately. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

10-06-2020, 10:48 AM	#5
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,472	Re: Viscous clutch fan for SBC 350 Looks good. If you have any pics of the shroud before installation, might post those up as well. And maybe some pics of that AC compressor bracket. Might be useful to folks wanting to add an aftermarket AC to a truck. Your results with the clutch are similar to mine. I run a standard duty clutch and it provides plenty of spin to the fan to keep things cool without sounding like a jet engine under the hood. The heavy duty version ran things too fast when the cooling just wasn't needed. Running a 195F thermostat here.

10-06-2020, 11:36 AM	#6
BlouDon Registered User Join Date: Feb 2019 Location: Centurion, Gauteng, South Africa Posts: 227	Re: Viscous clutch fan for SBC 350 I don't have pics but I do have these drawings (all dimensions in mm), that may help. No guarantees of course. As for the AC bracket, I used this: https://www.summitracing.com/int/par...make/chevrolet Attached Images __________________ Best regards, Philip Chev: '70 C10 (350 V8 / 700R4 ) & '59 Apache ( 235, 3-sp ) Jensen Interceptor '74: Mopar 440(EFI'ed) / 4L60e Jaguar: '72 E-type Coupe V12 & '74 E-type V12 Convertible & '80 XJS V12

10-06-2020, 12:09 PM	#7
BlouDon Registered User Join Date: Feb 2019 Location: Centurion, Gauteng, South Africa Posts: 227	Re: Viscous clutch fan for SBC 350 But then I thought, its only 4 countersunk cap screws and 2 x 10mm bolts to remove the cowling so I removed it quickly, a 5 min job.... Attached Images __________________ Best regards, Philip Chev: '70 C10 (350 V8 / 700R4 ) & '59 Apache ( 235, 3-sp ) Jensen Interceptor '74: Mopar 440(EFI'ed) / 4L60e Jaguar: '72 E-type Coupe V12 & '74 E-type V12 Convertible & '80 XJS V12

10-06-2020, 12:10 PM	#8
BlouDon Registered User Join Date: Feb 2019 Location: Centurion, Gauteng, South Africa Posts: 227	Re: Viscous clutch fan for SBC 350 Pictures are worth a 1000 words right? Attached Images __________________ Best regards, Philip Chev: '70 C10 (350 V8 / 700R4 ) & '59 Apache ( 235, 3-sp ) Jensen Interceptor '74: Mopar 440(EFI'ed) / 4L60e Jaguar: '72 E-type Coupe V12 & '74 E-type V12 Convertible & '80 XJS V12



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