I have a 305ci CFI V8 and my mechanical fan is rubbing against the bottom of the fan shroud. How do I fix that without cutting out a section?

 

Replace the motor mounts probably. Both items (fan and radiator) are in a fixed position. The (assuming original) rubber motor mounts collapsing would be my guess.
Unless the shroud has been taken off before and not replaced right or, the radiator isn't stock .

 

How would I know that my motor mount are collapsing?

my radiator and everything is pretty much stock.

 

You should have a 'clamshell' motor mount



If the centerline of the mount bolt (the long one though the mount) is close to touching the crossmember, it's bad.

I know that probably isn't a clear explanation but, that the best I can give you in my current state of mind. Typing is challenging enough....

 

you were right it is the motor mounts

found out why my mechanical fan was rubbing against the fan shroud. My motor mounts are on there way out and I have a performance aluminum mechanical fan. I thought it was stock. I think I will get some Energy Suspension polyurethane motor mounts. Any suggestions?

http://www.summitracing.com/parts/ENS-3-1130R/

 

Just keep in mind with those you have to take the old mounts apart and use those as inserts. Poly mounts will also add a bit more of noise and vibration into the car.

I personally opted to just put new rubber ones in my 'bird. I figured they lasted as long as they did. It's personal preference though. either way, it's quite a bit of work to replce the mounts.

Personally (which I did with my ex-'84), if the mounts aren't just total trash, I'd consider just putting in an elect fan. It's less clutter (fan shroud), eases stress on the WP bearing, reduces drag on the motor (free HP) and helps mpg.

Mind you, personl prefrence and just my opinion.

 

will the poly mounts destroy the car or will it eventually break in and stop making noise and vibration?

the electric fan looks awesome what do you suggest. But that is for sometime in the future.

 

If you engine is mostly stock, you probably won't notice a huge difference over (new) stock mounts as far a vibration (from a higher Hp motor and lumpy cam). So I wouldn't worry about it shaking the car apart.

Noise is just more or less resonant engine/drivetrain frequencies, it won't really go away due to the fact poly is less flexible (elastic, I guess). Again, not much but, more than rubber.

Something stock or a v6 stock fan would easily do on a stock 305.

I have a v6 grand prix fan on my 91, does what is should. mid 90's, ultra humid, A/C, 195°F from parking lot to driveway (28 mile trip).

The single fan on my duals for the 'bird kept it at a steady temp.

The flexalite electric on the '71 is as useless as as spitting on the radiator to keep it cool...

 

i think i will get factory GM rubber mounts