NOS Fan Clutch, mystery?

[John R.]

Okay, I have a 3916141 in the GM box NOS fan clutch stamped CK, big block. However, it does not look like what I am accustomed to seeing. Does anyone know what I have and its applicability? Thanks in advance for any assistance, John.

[Jim S.]

Re: NOS Fan Clutch, mystery?

If I understand what your are asking, you have a Schwitzer clutch . It looks different than the Eaton clutch with the coil in front . Both were used on C2s

As to it exact use I think , but am not sure, that the Schwitzer clutches were date stamped on the shaft somewhere , so while looking correct it may not be "perfect" for all years .
Better minds than I will chime in I'm sure .

[John R.]

Re: NOS Fan Clutch, mystery?

Jim, thank you for the reply. As I go back and read my post, it is a bit unclear. Sorry about that!

I've added a photo of a typical used C2 Schwitzer clutch stamped CJ, so the face difference can be seen. The NOS clutch is the one with the GM box.

Questions: would the NOS Schwitzer clutch (stamped CK) be correct for a '67, 427 vette given the configuration of the face? If this NOS Schwitzer clutch is meant for another application, what would it be? Personally, I have not seen this face configuration before, but perhaps some members have.

Thanks again!

[Jim S.]

Re: NOS Fan Clutch, mystery?

Oh ! Now I get it . I am not familiar enough with Schwitzers to have noticed that face was different.
So while I stand by my previous statement that better minds than mine will know and chime in , how about this attempt for starters.

From Corvette Central :

68-70 FAN CLUTCH - SCHWITZER STYLE - 327 / 350





1968-1970 Schwitzer Style Fan Clutch Correct reproduction Functionally correct in every way Flat rectangular Bi-Metallic thermostatic element Stamped CJ 2-year warranty

[Joseph K.]

Re: NOS Fan Clutch, mystery?

I would be suspecious of the CK stamp as my two year old grand daughter my have stamped that from the way it looks. Bought a sending unit once that was nos only to find out that the original in the box had sold and the the used one put in its place. Stamp should be crisp.

[Joe L.]

Re: NOS Fan Clutch, mystery?

Okay, I have a 3916141 in the GM box NOS fan clutch stamped CK, big block. However, it does not look like what I am accustomed to seeing. Does anyone know what I have and its applicability? Thanks in advance for any assistance, John.

John------


First of all, at the time GM was using fan clutches supplied by 3 different manufacturers---Eaton, Switzer, and Delco. As far as I know, any of these manufacturers could have supplied fan clutches to PRODUCTION and SERVICE for any given part number or broadcast code (the broadcast code was specific to a given part number, though).

The GM #3916141 was never the original part number for a fan clutch used for any 1967 Corvette. The initial applications for the 3916141 were some 1967 Chevrolet passenger cars with big block or 6 cylinder engines. 1967 Corvettes with 327 were usually originally equipped with fan clutch GM #3814560 although a few other fan clutches optional for PRODUCTION may also have been used. The GM #3814560 fan clutch was discontinued from SERVICE in May, 1973 and replaced by the GM #3916141.

1967 Corvettes with 427 were usually originally equipped with fan clutch GM #3857531 with broadcast code "CT". This fan clutch remained available in SERVICE until January, 1981 when it was discontinued and replaced by the GM #3916141.

1968-70 Corvette small blocks were usually equipped with fan clutch GM #3916139. Other than possible calibration differences, the only difference between the GM #3916139 and 3916141 was the shaft length with the 3916141 being slightly shorter. The 3916139 was discontinued from SERVICE in January, 1974 and replaced by the GM #3916141.

1968-70 Corvettes with L-36, L-68, and LS-5 were usually equipped with fan clutch GM #3937771. This is the "dog dish" clutch. It was discontinued from SERVICE in February, 1980 and replaced by the GM #3916141.

1968-69 Corvettes with L-71, L-89, or L-88 were usually equipped with the GM #3916141 fan clutch.

From the above, you can see why a lot of folks think that the GM #3916141 was the original fan clutch used for all 1967-70 Corvettes. But, the truth is that it is only SERVICE for most of them. In fact, it was SERVICE for all 1960-70 Corvettes but original only for some 1968-69 Corvettes.

All of the 3916139 fan clutches I have ever seen were Switzer-manufactured clutches. This is what my 1969 was originally equipped with. However, I seem to recall that either my original and/or one or more of the several I purchased over the first 3 or 4 years (I always thought that my fan clutches were going out) were the face style you show above. I still have most of them somewhere around here. So, I expect that at least during the 1969-74 period the 3916141 could have been either style, too. Plus, we KNOW that the 3916141 was manufactured by both Eaton and Switzer.

[John R.]

Re: NOS Fan Clutch, mystery?

Joe, excellent information and thank you.

So in summary the NOS clutch pictured would work, but would not be correct in appearance for a 67, 427. However, it would work and possibly be correct in appearance for earlier big block C3 corvettes, such as L71, L89 and L88, or earlier C3 small block, noting shorter shaft length and possible calibration differences. Do I have this correct?

[Joe L.]

Re: NOS Fan Clutch, mystery?

Joe, excellent information and thank you.

So in summary the NOS clutch pictured would work, but would not be correct in appearance for a 67, 427. However, it would work and possibly be correct in appearance for earlier big block C3 corvettes, such as L71, L89 and L88, or earlier C3 small block, noting shorter shaft length and possible calibration differences. Do I have this correct?

John------


Yes.

[Jerry H.]

Re: NOS Fan Clutch, mystery?

Go to Parts Plus. Just got one on Ebay from them. Punch in 391614. The fan I got is for 1962 after 2000 something. Looks like the one in 61-62 judging manual. $139.00.

[Jerry H.]

Re: NOS Fan Clutch, mystery?

I just Googled 3916141 and the fan clutch is correct and they have pictures. That is what I got

[Joe L.]

Re: NOS Fan Clutch, mystery?

I just Googled 3916141 and the fan clutch is correct and they have pictures. That is what I got

Jerry------

The GM #3916141 is, as far as a 1962 goes, a SERVICE replacement for the original fan clutch and, thus, functionally correct. However, it is not the original fan clutch used for a 1962 Corvette (or, any 1960-67 Corvette). While it may be somewhat similar to the original, it is not, with respect to configuration, correct.