CRG Discussion Forum
Camaro Research Group Discussion => Originality => Topic started by: 68Zproject on March 16, 2008, 02:08:43 AM
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Is the main difference in the solid lifter fans and the low perf. ones the bolt cir dia. for the fan clutch? Are both the fans the same diameter (18"s), shape etc. Reason I am asking is, the Z28 ones are ridiculously priced and if the others are functionaly the same, you could just get the right clutch for the cheap one and have the same results?
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Functionally, the 5-blade fans and clutches with a 3" bolt circle will work, but they're not judging-correct. Z/28 and L-78 used the clutch and fan with a 3-1/4" bolt circle.
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You can see that here:
http://www.camaros.org/coolingsystems.shtml
"Fan for L78 and Z28 and 1968 L34/L35 with K02
The 3871276 fan was used on the 1967 and 1968 Z28 and L78, as well as 1968 L34/L35 with K02. The bolt circle diameter for the clutch-to-fan attachment was 3.25-inch. It thus required a different clutch unit than the fan clutches used with the AC or K02 hydraulic lifter engines.
Five-Bladed Fans for 67-68
(Note the difference in the center hole diameter.)"
So, John, by "functionally" are you telling 68Zproject that the 3" bolt circle fan and clutch will fit or does it require some modification?
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Both fans work the same. I have an original one on green 68 Z and the smaller dia. one on my blue 68 Z . I have looked for an orig. fan for the blue car but the price scares me off. When i bought the blue car the original owner told me he had a flex fan on the car since the early 70s because he hated the noise the original clutch fan made. Said he remembers throwing out the original.
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Said he remembers throwing out the original.
Nice. :'(
I'm going to do what firez did. That's why I needed to know if they were functionally the same. Some day when I win the Lotto I'll get the real fan. Thanks much. ;D
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Yes, the 3" hole fan blade will work fine. Try to get one that has four rivets instead of five. The 3" fans come both ways. Just buy a clutch to match it and use as is.
Jerry
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Are the 4 rivets better in function ot do they just look more like the 3.25"?
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Are the 4 rivets better in function ot do they just look more like the 3.25"?
The original Z/28 fans use 4 rivets per blade.
Paul
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And to answer the original question, there was a difference in function or they wouldn't have used the unique part. But it's obviously not much of a difference... :)
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Jerry's book just said the larger bolt circle was because of the higher RPM of the solid lifter engines. Other than that I mainly wanted to make sure it was the same diameter and the cooling would be the same.
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Dave Libby, an engineer from GM pulled the blue prints and that's what was stated on the prints about the diameter and why it was larger.
Jerry
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I'd like to have those blueprints and make a real repo out of quality stuff that looked and fit like the real thing, instead of skipping a house payment to buy one.