Almost a 64-65 w/AC 7-blade 18" fan, GM # 3853943

[David L.]

I recently purchased (but not by mistake) a very nice original 18" 7-blade fan with curve tipped steel blades. The measurement from the center of the hub hole to the tip of any blade is 9", making it an 18" fan. The blades measure 6 1/8" long and 4" wide measured on the arc (and 3 15/16" = 3.94" chord measurement). The shape of the blade is the same as those on a 3853943 fan. The pitch measures slightly less then 2 1/4". This agrees with the theoretical 34.5 degree angle of the blades of the 3853943 fan (sin 34.5 degrees X 3.94" = 2.23"). The blades are attached with 4 "dome headed" rivets per blade which would be correct for 1964 and most 1965 Corvettes w/AC (very late 65's seem to have "flat headed" rivets). The word "FRONT" is stamped on the center section of the fan. Based on the photos below and my description so far I'm sure that most 63-67 Corvette restorers would probably say it was an original fan for a 64-65 Corvette w/AC. The one problem with the fan is that it will NOT fit on an original 64-65 Corvette fan clutch because the bolt circle measures 3 1/4" instead of 3". This fan could be used on a 64-65 Corvette w/AC as long as you used a fan-clutch with a 3.25" fan bolt circle along with a W/P hub with a 1.75" bolt circle and I'm sure that most "judges" would think it was a 3853943 fan.

I know what the actual application is for this fan. Does anyone else?

[Wayne M.]

Re: Almost a 64-65 w/AC 7-blade 18" fan, GM # 3853943

....I know what the actual application is for this fan. Does anyone else?

OK, David; I'll bite. The mushroom head rivets tell me that it has to be a '63-5 manufacture (or later service, depending on inventory depletion; and if so, did service [to at least Jan 1970] have flat head rivets ?). Also, the unique tip shape, comparable to the Corvette "943" [see my big pic, below] and a review of my P&A30 catalogs tells me your large-hub example was not offered on any Chevrolet passenger car, or light trucks.

[David L.]

Re: Almost a 64-65 w/AC 7-blade 18" fan, GM # 3853943

Wayne,

I knew you would know something about this fan. I was told it came off a 1964 Buick LeSabre. According to my 1965 & 1970 Hollander manuals ( I do not have any vintage Buick parts catalogs) the fan is GM # 1351444 and used on 1964-1965 Buick LeSabre models w/AC or H.D. cooling. The time frame matches up with the 1964-1965 Corvette 327 w/AC 7-blade fan.

The fan-clutch that came with the fan was set up for a 3 1/4" bolt circle fan mounting and a 1 3/4" bolt circle W/P mounting which is quite uncommon. The fan mounting surface to the W/P mounting surface measures 1 1/4". This is much shorter than my original 1966 Corvette Schwitzer fan-clutch dated "SC 1-26-66" which measures about 1 25/32".

Dave

[Jack H.]

Re: Almost a 64-65 w/AC 7-blade 18" fan, GM # 3853943

Not only is the fan clutch's shaft different than MY Corvette, but look again at the face (1st pix). Observe the fluid reservoirs (out dents on either side of the inner circle) are essentially 'trapezoidal' vs. 'rectangular' in shape. That's characteristic of later era Eaton production vs. what was used in the early 60's...

[David L.]

Re: Almost a 64-65 w/AC 7-blade 18" fan, GM # 3853943

Jack,

I know that my Buick fan-clutch looks more like the fan-clutches on 1969 & newer GM models. My whole point of this thread was to show that the 64-65 Buick LeSabre w/AC 7-blade fan was almost identical to the 64-65 Corvette w/AC fan except for the bolt circle. I am sure that many NCRS judges could easily be fooled if my Buick fan was mounted on a 64 or 65 Corvette w/AC if one could find a fan-clutch that looks like a vintage clutch but has the (probably rare) 3.25"/1.75" bolt circle configuration.

Dave