1970 dated L-46 fan clutch?

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Hope this works.

http://www.ebay.com/itm/1970-CORVETTE-454-350-LT1-ORG-FAN-BLADE-CLUTCH-DATED-5-5-70-SC-350HP-370HP-390HP-/251690272290?pt=Motors_Car_Truck_Parts_Accessories&hash=item3a99e8c622&vxp=mtr

Bill

Bill------


This is a GM #3937771, not a GM #3916139.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill------


This is a GM #3937771, not a GM #3916139.

However, it is correct for a 70 sb?

Bill

[John H.]

Re: 1970 dated L-46 fan clutch?

Who rebuilds them?

Mike -

Dan KirkConnell, (813) 477-6217; $175, turnaround 3 weeks or less. K3vetteman@msn.com.

[David L.]

Re: 1970 dated L-46 fan clutch?

The 3937771 fan clutch was used with AC. Refer to the 1970 AIM (C60, sheet C1).
There is a NOS 3916139 fan clutch currently on Ebay (not mine, see link below).

Dave

http://www.ebay.com/itm/GM-NOS-SCHWITZER-FAN-CLUTCH-3916139-/221588959341?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3397bb306d&vxp=mtr

[Joe L.]

Re: 1970 dated L-46 fan clutch?

However, it is correct for a 70 sb?

Bill

Bill------


It was primarily a big block fan clutch. However, it was also used for 1969-70 small blocks with A/C.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill------


It was primarily a big block fan clutch. However, it was also used for 1969-70 small blocks with A/C.

Hi Joe,

Read a thread from back in 2008 where you said that there is conflicting information regarding the application of the 3937771.

I understand the confusion and I am wondering if the 3916193 was used on base motor with A/C. I thought that the 3937771 was also used on special HP applications and while the L46 did not alway fit this category the L46 did share some parts with the LT-1 that were not on base motors like the alternator pulley. The L46 used the deeper pulleys as well.

The L46 did share the copper radiator and shroud set up with the LT-1 as well.

Just a thought.

Bill

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Hi Joe,

Read a thread from back in 2008 where you said that there is conflicting information regarding the application of the 3937771.

I understand the confusion and I am wondering if the 3916193 was used on base motor with A/C. I thought that the 3937771 was also used on special HP applications and while the L46 did not alway fit this category the L46 did share some parts with the LT-1 that were not on base motors like the alternator pulley. The L46 used the deeper pulleys as well.

The L46 did share the copper radiator and shroud set up with the LT-1 as well.

Just a thought.

Bill

Bill------

Yes, I'd still say there is some confusion regarding the applications for the 3937771.

However, for 1970 the LT-1 was supposed to have used the same fan clutch as the base engine. For the base engine, the 3916139 was probably the most common one used. Inasmuch as the base engine and LT-1 used the 3916139, I would expect that the L-46 did, too.

Now, the above represents what was SUPPOSED to have been installed, not necessarily what was actually installed. GM P&A catalog information sometimes conflicts with the above so that fact introduces some "confusion".

Also, the 3937771 and 3916139 were functionally interchangeable without the need to change any other parts of the system. So, the factory could have installed either.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill------

Yes, I'd still say there is some confusion regarding the applications for the 3937771.

However, for 1970 the LT-1 was supposed to have used the same fan clutch as the base engine. For the base engine, the 3916139 was probably the most common one used. Inasmuch as the base engine and LT-1 used the 3916139, I would expect that the L-46 did, too.

Now, the above represents what was SUPPOSED to have been installed, not necessarily what was actually installed. GM P&A catalog information sometimes conflicts with the above so that fact introduces some "confusion".

Also, the 3937771 and 3916139 were functionally interchangeable without the need to change any other parts of the system. So, the factory could have installed either.

Thanks Joe.

Wonder which one is on Terry Ms original LT-1? Wonder if we should start a survey.

Bill

[Terry M.]

Re: 1970 dated L-46 fan clutch?

Thanks Joe.

Wonder which one is on Terry Ms original LT-1? Wonder if we should start a survey.

Bill

Bill,
If I could figure out what the physical difference is between the two fan clutches are, I might have a chance of answering your question, but alas nothing I read in the text gives me a clue.

[Bill L.]

Re: 1970 dated L-46 fan clutch?

Bill,
If I could figure out what the physical difference is between the two fan clutches are, I might have a chance of answering your question, but alas nothing I read in the text gives me a clue.

Hi Terry,

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

Thanks, Bill

Fan Clutch Corvette.jpg Fan Clutch Corvette 5-5-70.jpg

[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]

I am pretty sure it is Number 2, but I will check.
That sounds awful. I am surprised the censor bot doesn't strike out some of that.

[Paul O.]

Re: 1970 dated L-46 fan clutch?

Terry and Bill

Your 2nd photo is the configuration that I have always remembered being used. Here is a photo of a 1972 ZR-1 I know it is later then what we are talking about but that's what I think I remember. Now what were we talking about again?

[Gary B.]

Re: 1970 dated L-46 fan clutch?

I have a, what I would call a Photo 1 fan clutch dated 10-2-70 SC. Below is photo's from two 1970 LT-1's, s/n 2161 and 5774, both very original cars.. Getting a picture of the front of the fan is a challenge, with shroud and radiator in place. So, I hope these help.


Gary Bosselman

2161 Clutch.jpg2161 Front.jpg5774 clutch.jpg5774 Front.jpg

[Joe L.]

Re: 1970 dated L-46 fan clutch?

Terry and Bill

Your 2nd photo is the configuration that I have always remembered being used. Here is a photo of a 1972 ZR-1 I know it is later then what we are talking about but that's what I think I remember. Now what were we talking about again?

Paul-------


Pictured is a GM #3991426 which was used for 71-72. It has the same general configuration as the GM #3937771. However, the hub and pilot orifice are larger. It is not interchangeable with the 3937771 and cannot be used on 1970 and older applications without other modifications (i.e. water pump, pulleys and fan blade).

[Bill L.]

Re: 1970 dated L-46 fan clutch?

I have a, what I would call a Photo 1 fan clutch dated 10-2-70 SC. Below is photo's from two 1970 LT-1's, s/n 2161 and 5774, both very original cars.. Getting a picture of the front of the fan is a challenge, with shroud and radiator in place. So, I hope these help.


Gary Bosselman



[ATTACH=CONFIG]55966[/ATTACH][ATTACH=CONFIG]55967[/ATTACH][ATTACH=CONFIG]55968[/ATTACH][ATTACH=CONFIG]55969[/ATTACH]

Hi Gary,

This is the configuration I have seen most often. If the other fan clutch was used on al sb except with A/C there should be more around and there just are not any to be found . This is getting quite interesting.

Bill