Im putting together a shroud for my Nova just now realizing that the fan is within 1/4" of scraping the sides of my new shroud. Im already thinking I am going to have to size down from an 18" to at least a 17" for clearance, but just out of curiosity wonder if any one knows if the fan will grow in diameter when Im ringing out the motor or if it will just flex forward towards the radiator?
I don't know how much it will grow, but I saw a little sticker on an OE-style replacement flex fan that said "Do not exceed 4,000rpm." I've got a big reproduction steel fan on my '61 Suburban. I wouldn't run a flex fan... too many stories of them coming apart. -Brad
It won't grow in diameter, but i have been told that half of the blade should be in the shroud and half out to have it work at it's best.
My sons flex fan came apart while he was tuning the tri-power on his 30 sedan. Damn near cut his arm off missed him by inches only cost 600 for the new radiator. He still has pieces of it stuck in his shop wall and ceiling. If you going to run a flex fan always have your mother in-law tune your car, its a great way to get rid of her!! FLEX FANS ARE JUNK!!