1970 dated L-46 fan clutch?

[Terry M.]

Re: 1970 dated L-46 fan clutch?

Hi Terry,

How about pics? Which configuration is on the LT-1?

Thanks, Bill

[ATTACH=CONFIG]55961[/ATTACH] [ATTACH=CONFIG]55962[/ATTACH]

Bill,
I have confirmation that what is on my 1970 #2161 is as in photo #2. I have photos and another 1970 LT1 photo example on the way.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill,
I have confirmation that what is on my 1970 #2161 is as in photo #2. I have photos and another 1970 LT1 photo example on the way.

Thank you Terry.

This is very curious. Do you know of any L46 Original owner cars? Might b worth checking. I have two dated clutches like in pic 2. This might explain why very few, if any, have seen a dated clutch like Pic 1 for 70.

Bill

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Thank you Terry.

This is very curious. Do you know of any L46 Original owner cars? Might b worth checking. I have two dated clutches like in pic 2. This might explain why very few, if any, have seen a dated clutch like Pic 1 for 70.

Bill

Bill------


I can tell you that for 1969 my 300 HP was originally delivered with a 3916139 (pictured #1). I have a friend who is also the original owner of his early build 1969 L-46. His car has the 3916139, too.

For 1970, the AIM specifies that the 3916139 was to be used for 300 HP cars (in addition to a couple of other alternative clutches that are rarely, if ever, seen). For LT-1 applications, it specifies that the PRODUCTION part is to be used (that refers back to the 3916139). For applications with C-60, the 3937771 is specified.

For whatever reason, it appears that the 3937771 was much more widely utilized and contrary to the AIM.

By the way, the alternative clutches for the 1970 standard configuration were GM #3916140 and GM #5329100. I believe the GM #3916140 is an Eaton-manufactured unit with a "coil spring" thermostat. I believe it's identical to the 3916141 except that it has the slightly longer shaft used with small blocks. The 5329100 was a Delco-manufactured clutch with a "coil spring" type thermostat. As far as I can tell, neither of these were ever available in SERVICE.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill------


I can tell you that for 1969 my 300 HP was originally delivered with a 3916139 (pictured #1). I have a friend who is also the original owner of his early build 1969 L-46. His car has the 3916139, too.

For 1970, the AIM specifies that the 3916139 was to be used for 300 HP cars (in addition to a couple of other alternative clutches that are rarely, if ever, seen). For LT-1 applications, it specifies that the PRODUCTION part is to be used (that refers back to the 3916139). For applications with C-60, the 3937771 is specified.

For whatever reason, it appears that the 3937771 was much more widely utilized and contrary to the AIM.

By the way, the alternative clutches for the 1970 standard configuration were GM #3916140 and GM #5329100. I believe the GM #3916140 is an Eaton-manufactured unit with a "coil spring" thermostat. I believe it's identical to the 3916141 except that it has the slightly longer shaft used with small blocks. The 5329100 was a Delco-manufactured clutch with a "coil spring" type thermostat. As far as I can tell, neither of these were ever available in SERVICE.

Hi Joe,

Since mine is a 70 I have been observing various dated parts for a few years since by accident I kept coming up with the 3937771 dated fan clutches but never a 3916193. Up until now the evidence has been anecdotal for the most part.

I would think that the original poster might begin looking for a 3937771 fan clutch for his 70 L46 inasmuch as I suspect GM installed very few of the 3916193 from what we can tell so far. Granted this is only a few out of 17k + corvettes made in 1970. I wonder if anyone can verify a 3916193 on their original 70. I agree that this is just one of those instances where GM seems to have used a part different than called out in the AIM.

Should this be noted in a revised Judging Manual when it comes out?

Bill

[Kenneth H.]

Re: 1970 dated L-46 fan clutch?

I sent my fan clutch to Dan Kirkconnell last month and he did a great job. Turned it around in a week, and it looked brand new. See John Hinckley's post, above, for his contact info. However his price is a little higher than what John quoted.

[Mike F.]

Re: 1970 dated L-46 fan clutch?

I received a fan clutch from one of the above listed vendors this week, it does not have a flat front side to it. Will this pass muster for my 70 L-46 or does it need returned? I spent top dollar, I don't want to lose a point (and I want it to be correct). My picture files for 1970 small blocks all show the flat sided front as well.
This thread seems to go back and forth on what was actually used and what is correct. Most expect to see a flat front side, but if I read correctly the flat front side is NOT p/n 3916139.

[David L.]

Re: 1970 dated L-46 fan clutch?

Mike,

I once owned a 3916139 fan clutch stamped "CJ" made by Eaton dated "L27G" (Nov. 27, 1966). I will post a photo when I get a chance. I also believe that Schwitzer made a "CJ" fan clutch as well.

Dave

[Mike F.]

Re: 1970 dated L-46 fan clutch?

Mike,

I once owned a 3916139 fan clutch stamped "CJ" made by Eaton dated "L27G" (Nov. 27, 1966). I will post a photo when I get a chance. I also believe that Schwitzer made a "CJ" fan clutch as well.

Dave

Dave,

I appreciate the help, but I am specifically interested in 1970 correctness only. I don't want the thread to get side tracked with other years.

Thx again.

[Mike E.]

Re: 1970 dated L-46 fan clutch?

Mike,
I bought my 70 L46 from the original owner. It still has original hoses and clamps, and 1 of 2 belts is still the original. It has the 2nd pictured style of fan, dated 2 16 70 SC. The car is #6243. Hope that is helpful. I have no idea which part number it is.

[David L.]

Re: 1970 dated L-46 fan clutch?

Enclosed is an original clutch fan ink stamped "EATON", "CJ", and "L276" (Nov. 27, 1966) in the top photo and a NOS 3916139 fan clutch made by Schwitzer ink stamped "CJ" and stamped "12-17-69 SC" (Dec. 17, 1969) on the hub in the bottom photo.

Dave

[Bill L.]

Re: 1970 dated L-46 fan clutch?

I received a fan clutch from one of the above listed vendors this week, it does not have a flat front side to it. Will this pass muster for my 70 L-46 or does it need returned? I spent top dollar, I don't want to lose a point (and I want it to be correct). My picture files for 1970 small blocks all show the flat sided front as well.
This thread seems to go back and forth on what was actually used and what is correct. Most expect to see a flat front side, but if I read correctly the flat front side is NOT p/n 3916139.

Hi Mike,

We have yet to see an original 70 with this type of fan clutch. The other type seems to be the one used in 1970 regardless of what the AIM calls out.

I have seen several on ebay over the last several years with various dates for a 1970 Corvette. Never have I seen one like is pictured.

I would keep asking for more 70 owners to chime in on the fan clutch. I recently saw an original owner 1970 L46 Convertible in rough shape but original and it has the 71-72 type fan clutch with a 70 date code. Owner was asking crazy $$$ or I would have bought it. It was VERY rough! Stripped except it was an M21 with L46.

Bill

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Enclosed is an original clutch fan ink stamped "EATON", "CJ", and "L276" (Nov. 27, 1966) in the top photo and a NOS 3916139 fan clutch made by Schwitzer ink stamped "CJ" and stamped "12-17-69 SC" (Dec. 17, 1969) on the hub in the bottom photo.

Dave

Dave------


The two alpha character broadcast codes on the fan clutches were there primarily to allow assembly line workers to identify the correct clutch for the application. Part numbers were not important to them. For 1970 base engine cars, the GM #3916139 was the primary clutch specified. However, the 3916140 (Eaton) and 5329100 (Delco) clutches were optional. So, I expect that all three would have carried the "CK" broadcast code since, as far as the assembly line was concerned, any one of them were the same and all are functionally equivalent. The 3916140 and 5329100 were never available in SERVICE, though.

[David K.]

Re: 1970 dated L-46 fan clutch?

This came up awhile back and I said at that time that Americas Finest Corvettes, (driveline advertiser), www.corvetteusa.com repros them. I ordered one for my big block but haven't gotten it yet due to it being back-ordered. I cannot at this time attest to its performance vs an original and it will be awhile before I can since the car is undergoing restoration.

Dave

FWIW I never received the fan clutch I ordered from Americas Finest so I called them a couple of weeks ago to see if my order had fallen thru the cracks. As it turns out they quit selling them because it was a crappy repro; in their words. They are refunding my money but I haven't seen that either.

Dave

[David L.]

Re: 1970 dated L-46 fan clutch?

Dave------


The two alpha character broadcast codes on the fan clutches were there primarily to allow assembly line workers to identify the correct clutch for the application. Part numbers were not important to them. For 1970 base engine cars, the GM #3916139 was the primary clutch specified. However, the 3916140 (Eaton) and 5329100 (Delco) clutches were optional. So, I expect that all three would have carried the "CK" broadcast code since, as far as the assembly line was concerned, any one of them were the same and all are functionally equivalent. The 3916140 and 5329100 were never available in SERVICE, though.

Joe,
I suspect that the factory installed 3916139, 3916140, and 5329100 fan clutches all were ink stamped "CJ".

I once owned a NOS "CZ" fan clutch , GM # 3946050, ink stamped "CZ", "EATON", and "A17J" (Jan. 17, 1979; I assume) as well as an almost mint used "CZ" fan clutch made by Schwitzer (bar strip type with "THIS SIDE UP" stampings) ink stamped "CZ" and stamped "1-27-69-SC" on the hub. The 3946050 fan clutch is listed in my 1969 Camaro AIM for 396 engines (L78). These 2 fan clutches measure about 7 1/4" in diameter.

BTW, the "CK" stamped fan clutch (GM # 3916141) used on BB engines has a shorter shaft length than the "CJ" fan clutch (shorter by about 0.3").

Dave

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Joe,
I suspect that the factory installed 3916139, 3916140, and 5329100 fan clutches all were ink stamped "CJ".

I once owned a NOS "CZ" fan clutch , GM # 3946050, ink stamped "CZ", "EATON", and "A17J" (Jan. 17, 1979; I assume) as well as an almost mint used "CZ" fan clutch made by Schwitzer (bar strip type with "THIS SIDE UP" stampings) ink stamped "CZ" and stamped "1-27-69-SC" on the hub. The 3946050 fan clutch is listed in my 1969 Camaro AIM for 396 engines (L78). These 2 fan clutches measure about 7 1/4" in diameter.

BTW, the "CK" stamped fan clutch (GM # 3916141) used on BB engines has a shorter shaft length than the "CJ" fan clutch (shorter by about 0.3").

Dave

Dave------


That was my error. I meant to say "CJ" and NOT "CK". I can't edit it now, though.