Mr D.

I picked up a 1971 350 w/ AC project that was missing the fan shroud and spent the better part of the morning installing a reproduction shroud but when I went to install the fan it was hitting the shroud along the top and right hand side, left side and bottom were ok.

The fan that was on the car is PN 14030071, 17 1/2" 7 Blade and has a date code of D82 which leads me to believe its a 1982 GM something fan.

RPO C60 in the AIM calls for a 3992095 fan with a note that states the PN was 3955182 and that RPO LS5 used the same fan assembly.

In Group 1.064 of my 1982 GM parts manual it list 71-73 350 w/AC as PN 3991427, 17 1/2" 7 Blade.

In Group 1.064 of my 1982 GM parts manual it list 71-73 454 w/AC as PN 3992095, 17 1/2" 7 Blade.

So it's safe to assume that a 17 1/2" fan should fit this car regardless of what year it came from or so I would think. This shroud is pretty straight forward for mounting, 2 holes at the bottom and two at the top so no way to adjust it for more clearance and I would need a 1/4"-1/2" which is a lot.

I read a few threads on here about these reproduction fan shrouds being a crap shoot on fitting property. Anyone run into this?

I have a couple other GM fans I'm going to try tomorrow but I'm thinking I need to pull this shroud and send it back for a refund.

Thoughts?????

TimAT

Check your motor and trans mounts too- If the trans mount is soft, the front of the engine will tip up and fan could hit at the top. Motor mounts, the front goes down. I just went thru this little exercise when I installed poly mounts.

Mr D.

My mounts are good, I have the same problem and measurements in the below link.



https://www.corvetteforum.com/forums...-issues-2.html

Alan 71

Hi MrD,
It appears to me the fan for a 71 350 engine with a/c should be #3991427 which superseded fan #3955182.
I'm not sure how the fans may have changed based on their part number.
Do you get the feeling that IF the shroud was positioned 'just right' the fan would be able to operate in the shroud's opening?
Is the shroud too small?
Is the shroud not able to be positioned to accept the fan?
Is the engine tipped slightly?
Is the fan clutch extending the fan 'into' the shroud far enough
???
Regards,
Alan

Mr D.

More info, I went dumpster diving in my spare parts and pulled out a fan I attempted to install on my 427 C2 that didn't fit due to it rubbing on the fan shroud. The correct size fan for this setup was a 17.5" (66 427), bought that and problem was solved.

So I attempted to use this fan on the 71 and it also rubs the shroud at the 12, 2 & 4 o'clock position. I measured this fan and its 18", I than compared the fan off the 71 to this fan and they are the same 18".

Pretty sure at this point it's a fan issue and not the shroud. I will order a new fan tomorrow and see how it fits.

The fan clutch is a Easton A101A, 3.25" on center bolt pattern with a 1.5" shaft.

domenic tallarita

I had the same problem with my 67 coupe BB. Everything was new as I was finishing up a frame off restoration.
The fan hit as yours did.
I tried shifting the engine, it helped a bit but not enough. The fan is 17 1/2".
I bought the engine mounts from one of our corvette suppliers. I spent a bunch of time looking things over and all pointed to the engine mounts.
My biggest concern was that I checked the frame when it was off to see if the frame shop did the job right back in 1971 when I bought the car wrecked. Well it was off a bit so I tweeked it back to where it was supposed to be. My first thought was "did I screw things up when I tweeked the frame back to specks?
I went back to the engine mounts and looked at them for hours to see if they could be the problem. Well I went out and bought new mounts at the local parts house, took the repo mounts off and mounted the local parts house mounts and that solved the problem.
My schroud was the one I had on the car since 1971. I did a bit of hole work also to get the fan spacing.
What I am saying here is that the double priced mounts from the Corvette store we buy our parts from were way off. And not only were the engine mounts bad but early in my frame off when I was fitting the exhaust thru the frame, it would hit the frame. So off came the rear mount and I took it to the local auto parts house and compared it to theirs and there was a 1/8th difference. The one the corvette supplier sent was for the side pipe cars. I called them to let them know that the mounts were the wrong part # so they could save some other from having a problem and they snuffed me off saying "we don't make mistakes like that". Could this be a China problem? The mounts I bought locally were 1/2 the price!


Dom

Mr D.

Thanks Dom, I looked at the mounts yesterday and they appear to be original to the car but I thought the fan was too.

I too have run into the mount problem on past C2's and the "safety" mounts seem to cause nothing but problems.

Mr D.

Update, the correct 17.5" fan from Corvette America fix the problem.