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Fan blade slight contact with big block shroud issue

mbc0724

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I replaced my lightweight aluminum aftermarket radiator yesterday with a factory reproduction 959 26" on my 1971 440. All went smoothly. However, at engine startup there was a slight sound indicating the fan was hitting the shroud. On inspection, the space between the fan at the top and the shroud is very small--much less than an eighth of an inch (see photo). I think that is where the contact is. But since everything bolted in just fine, I cannot figure out what the issue is to cause the clearance problem since it did not exist before the change. I did notice that the top of the shroud where it mates with the radiator is bowed out a bit (see photo). If I press it in toward the radiator with my hand, the space issue with the fan is resolved. Perhaps the shroud warped slightly to the old radiator and needs to be replaced? Otherwise, I cannot see where I can adjust things any other way. The fan and radiator and shroud bolt in the way they bolt it--there is no adjustment that I am aware of. The rest of the blade has very good clearance--see last photo.

Thoughts?

Thanks!

fan100.jpg


fan 200.jpg


fan300.jpg
 
Last edited:
is it plastic? .... if "squeezing" the plastic shroud into shape fixes the problem, use a heat gun........ carefully and creatively

or simply slot a couple of holes and slide it up a smidge
 
is it plastic? .... if "squeezing" the plastic shroud into shape fixes the problem, use a heat gun........ carefully and creatively

or simply slot a couple of holes and slide it up a smidge
Yes but will it stay?
It's possible that it will see 200 degrees and if anything it's going to sag downward.
 
The motor will move upwards when load is applied. I would move the rad up if possible.
 
As said raise the radiator and elongate the shroud holes and raise that if needed.
 
Is it the correct fan for your car? Some are 18 inches and some are 18 1/4 . Did you have the shroud on the other radiator?
 
Is the fan blade at least 1/3 in shroud?
 
Simple version - loosen radiator and slide up a bit, then retighten bolts. You can do the same on the shroud
 
Thanks for all the good comments! Transmission mount on the four-speed seems fine. This was the same shroud as the last radiator. It's about an 18 inch but need to measure again. It's the standard 7-blade with clutch on the big block Trac Pak car. I will check the 1/3 comment--was not familiar with that--sounds interesting. I think the upper radiator bolts/nuts are fixed in the radiator support panel on this car (71 Charger). I don't think I can adjust the radiator height without drilling new holes, but will look at it again. The suggestion to enlarge/elongate the shroud bolt holes sounds promising. I don't need much more space. Just a little.
 
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