69 vette - Fan clutch - p/n ?

[Frank Bernier]

Hi guys
what would be the correct part number for a fan clutch for a early 69 vette

427
without a/c

3937771
or
3916141
or
something else

Thanks Frank

[Joe L.]

Re: 69 vette - Fan clutch - p/n ?

Frank-----

Most likely, it would be a GM #3937771. However, I would not rule out the possibility that a GM #3916141 could have been used.

There is no way to positively ID the part number of any of these units since the number is not stamped anywhere on them. Sometimes, there may be a "vestige" of a broadcast code which can help identify them, though. The GM #3937771 has a very unique configuration, however, and it can be easily identified. It's unusual characteristic is a smooth "pie plate" dish around the perimeter of the otherwise vaned face of the unit. Also, it's a Sweitzer-manufactured clutch with the rectangular "bi-metallic" thermostat. I don't think that Eaton manufactured any of the 3937771 clutches.

The GM #3916141 was a different style fan clutch with no "pie-plate". I used to think that these clutches were manufactured only by Eaton. However, they were not. The 3916141 was manufactured by BOTH Eaton and Sweitzer and I am virtually certain was used interchangeably in PRODUCTION, but I think that Sweitzer by far predominated in the 68-70 period. The Eaton version had the stamped steel face with coil-type thermostat. The Sweitzer version had the vaned-type face with rectangular "bi-metallic" thermostat. Functionally, they were equivalent.

The Eaton version of the 3916141 is still available today from GM. However, the configuration of the stamped steel face is somewhat different from the version used in days-of-old.

[Frank Bernier]

Re: 69 vette - Fan clutch - p/n ?

please check out the image
would that be a 3937771 ??? .. with your experience
-Thanks Frank

[Joe L.]

Re: 69 vette - Fan clutch - p/n ?

Frank-----

It's definitely NOT a GM #3937771. However, it does look like a big block clutch.

[Frank Bernier]

Re: 69 vette - Fan clutch - p/n ?

about this clutch ?

is this a 3937771

or maybe 3916141

-Frank

[Joe L.]

Re: 69 vette - Fan clutch - p/n ?

Frank------

The clutch pictured is a Sweitzer-manufactured version of the GM #3916141.

[Jack H.]

Looks to me like it's identical...

to a Ford C4SA-B fab clutch as used on mid-60 era Ford BB's... What's embossed on the side of the drive hub?

[Frank Bernier]

Re: Looks to me like it's identical...

does anyone have a picture for a 3937771 fan clutch .... what does it look like ?

[Joe L.]

Re: Looks to me like it's identical...

Frank----

It looks like this

[Joe L.]

Re: Looks to me like it's identical...

Here's a photo of the rear of the 3937771

[Jack H.]

Re: Looks to me like it's identical...

Side photo is the judging telltale... The center of the face surrounding the bi-metal actuator has aluminum fins that protrude upward to almost the same height as the surrounding outer ring. There's another, similar, Schwitzer fan clutch that looks identical with the exception being the fins in the face center are MUCH lower in profile and fall well below the plane of the outer ring.

Last, you can't see from just Joe's picture. But, note this is a 7-inch (width) clutch vs. the smaller OD (6-inch) clutch units used on mid-year and base engine Shark cars...

[Frank Bernier]

Re: Looks to me like it's identical...

thanks alot for the pictures Joe

was the 3937771 made only for corvette ?
or did GM used it for other cars also ?
and how many years was it used ?

-Frank

[Joe L.]

Re: Looks to me like it's identical...

Frank-----

The GM #3937771 fan clutch was used only for model years 1968, 1969, and 1970. The only application I can find for it is Corvette.

[Jack H.]

Re: Looks to me like it's identical...

Whether factory original or not, I've found the elusive critter on full sized, A/C equipped Chevy's (Caprice) and wagons from the same era + some Cadillacs AND a handful of Fords...

[Joe L.]

Re: Looks to me like it's identical...

Jack-----

There may very well be similar APPEARING clutches used on other vehicles. However, that does not mean that they are the same part.