cooling of a big block

[bonks69]

Has anyone found a servere duty fan clutch that will fit a L68 fan?
Would prefer a fan clutch out of a truck, much more tighter. Have found some but, they just don't fit thru the hole in the fan, and i really don't want to put in electric fans,trying to keep the factory look. Car runs cool at highway speeds (160), but at idle it starts to heat up. already have alum. rad, new motor, new water pump, and new 160 thermostat any help will be great.

 

[Jack]

Has anyone found a servere duty fan clutch that will fit a L68 fan

Welcome aboard CACC! Go to www.haydenauto.com ... download their pdf catalog ... it has lots of specs & dimensions ... also a full explanation of how clutches work & the differences between the several grades that have differing rates (ie severe duty vs hd). Info there is great & may help dispell some myths. Hayden is an old line, major manufacturer of fan clutches. With your dimensions in hand you can search their pdf catalog.

You might find the operating characteristics of severe duty objectionable (noisy, power-robbing). You didn't mention if you have a new fan clutch ... have you tried a NEW NON-severe? Also, have you verified your new t'stat really opens when it should & opens fully (put in a pot on stove w/ t'meter)? Is your shroud in place and matched to fan size? Are your shroud-to-rad seals in place?
JACK:gap

 

[427]

Are you aware that some fan clutches can be adjusted? Long ago, "Corvette World" magazine (no longer in circulation) had an article on this subject. I scanned the directions and had it on my old website back in 1997 ... Here it be again: http://www.corvette.net/cac/fan_clutch

Hope that helpz,
Jack
(Yeah ... Another Jack)

 

[Jack]

Are you aware that some fan clutches can be adjusted? Long ago, "Corvette World" magazine (no longer in circulation) had an article on this subject. I scanned the directions and had it on my old website back in 1997 ... Here it be again: http://www.corvette.net/cac/fan_clutch

Hope that helpz,
Jack
(Yeah ... Another Jack)

427 (Jack)
VERY GOOD! Didn't know about that. Thanks for the tech article & Welcome to CACC!
JACK:gap

 

[jonstr]

Do you have a fan shroud?

Has anyone found a servere duty fan clutch that will fit a L68 fan?
Would prefer a fan clutch out of a truck, much more tighter. Have found some but, they just don't fit thru the hole in the fan, and i really don't want to put in electric fans,trying to keep the factory look. Car runs cool at highway speeds (160), but at idle it starts to heat up. already have alum. rad, new motor, new water pump, and new 160 thermostat any help will be great.

Out of curiosity, do you have a fan shroud? I ask because most L88s did not come with a shroud and are notorious for overheating unless they're going fast. Since my L88 has a TH400, it also has a fan shroud and it never runs hot - even in the killer Arizona summer. I know of no other difference in the cooling systems except for the shroud.

 

[67HEAVEN]

Are you aware that some fan clutches can be adjusted? Long ago, "Corvette World" magazine (no longer in circulation) had an article on this subject. I scanned the directions and had it on my old website back in 1997 ... Here it be again: http://www.corvette.net/cac/fan_clutch

Hope that helpz,
Jack
(Yeah ... Another Jack)

That's an excellent article, Jack!
Thanks.

 

[M&W's72vette]

Cooling of a big block

On my 72 I did little remodeling last spring, I dropped the radiator down just above the crossmember and stood it up straight. Then I completly boxed in the radiator with aluminum and built ducts that run up under the nose to scoop air in and force it through the radiator. Before the mods the car would run cool in city traffic but would run hot out on the road. Now it runs cooler out on the freeway cruising at 80 mph. I had to cap off the filler neck on the rad and build one that goes in the top hose just off the thermostat. I am running twin electric fans rated at 2500 cfm and have them on a thermostat in the head that turns them on at 190. I also had to remodel the hood hinges to get the front of the hood to clear the ductwork so I copied the C-5 hinges and that makes the nose of the hood come up as it opens. I am running a street and performance serpentine belt setup but still have the stock rotation water pump so I am probably losing some water circulation capacity from that setup. The only thing I need to change is to have the front air dam closer to the wheels so I dont bump it on parking barriers, curbs ect. Other than that its worked good. Guess I need to learn to back in...