C3 69 Pulley-Blues

[John A.]

Issues with new belts:

I guess the first thing is to veriify the correct pulleys. This is what I have on the car right now:

• Do all these pulleys look correct?
• Is there some variation in belt configuration base on the fact that it was a E69???

All and any help appreciated.

Thanks

[Joe L.]

Re: C3 69 Pulley-Blues

Issues with new belts:
I guess the first thing is to veriify the correct pulleys. This is what I have on the car right now:

• Do all these pulleys look correct?
• Is there some variation in belt configuration base on the fact that it was a E69???

All and any help appreciated.

Thanks

John-----


Your pulley part numbers are all correct. However, the 3889372 waterpump pulley should be a 3 groove pulley, not a 2 groove.

The idler pulley does run on the back side of the waterpump belt (1968 didn't, though; it was a conventional grooved pulley idler). Anyway, the belt for the "with idler pulley" (i.e. with C-60) has to be longer than the belt for "without idler pulley" (i.e. without C-60). You never get the idler pulley to work with the captive belt used for non-C-60 applications.

[John A.]

Re: C3 69 Pulley-Blues

Thanks Joe... You are correct - that WP pulley is a 3 groove... I fat fingered it...

So, back to the WP belt and idler pulley.... take me through the configuration because I'm missing something here....

Belt 1 - WP/crank/idler(on the back side of the belt)
Belt 2 - WP/crank/PS
Belt 3 - PS/Alt
Belt 4 - WP/SMOG/AC

So, with this set up, why the longer Belt 1 with or without AC?

Thanks

[John A.]

Re: C3 69 Pulley-Blues

Hey Joe...

One more question... I have seen vendors offering a cast iron HB pulley... which they describe as correct for 65 - 69 BB up to VIN 24,000... what is the significance of the cast iron over the stampped steel?

Thanks again

[Joe L.]

Re: C3 69 Pulley-Blues

Hey Joe...

One more question... I have seen vendors offering a cast iron HB pulley... which they describe as correct for 65 - 69 BB up to VIN 24,000... what is the significance of the cast iron over the stampped steel?

Thanks again

John-----


The 3863108 cast iron pulley and the 3921923 stamped steel are functionally interchangeable. For 65-67, the 3863108 was used for all big blocks.

For 1968-69, things changed. In general, the 3863108 was used for L-71, L-89, L-88 and ZL-1 and the 3921923 was used for L-36 and L-68. However, there were variations of this and, in some cases, I believe the 3921923 was used for L-71, L-89, L-88 and ZL-1 and the 3863108 used for some L-36 and L-68 applications.

The 3921923 was used for all 70-74 Corvette big blocks except 1971 LS-6.

[Joe L.]

Re: C3 69 Pulley-Blues

Thanks Joe... You are correct - that WP pulley is a 3 groove... I fat fingered it...

So, back to the WP belt and idler pulley.... take me through the configuration because I'm missing something here....

Belt 1 - WP/crank/idler(on the back side of the belt)
Belt 2 - WP/crank/PS
Belt 3 - PS/Alt
Belt 4 - WP/SMOG/AC

So, with this set up, why the longer Belt 1 with or without AC?

Thanks

John-----


The water pump to balancer pulley belts used for with and without C-60 for a big block are different, not the same. The with C-60 belt is longer.

[John A.]

Re: C3 69 Pulley-Blues

Joe...

So, the belt (3940990) (groove 1 - WP pulley) is 1" longer than (3952336) if the car was configured with AC... ????

But why the longer belt... the idler rides nice on the short belt as well...

The AC belt runs off of (groove 3 - WP pulley) the outer groove...

Hence, I dont understand why a car with AC gets the longer WP belt - it seems to have no affect on the operation of the AC system.... and, it doesent really work with the idler...???

[Joe L.]

Re: C3 69 Pulley-Blues

Joe...

So, the belt (3940990) (groove 1 - WP pulley) is 1" longer than (3952336) if the car was configured with AC... ????

But why the longer belt... the idler rides nice on the short belt as well...

The AC belt runs off of (groove 3 - WP pulley) the outer groove...

Hence, I dont understand why a car with AC gets the longer WP belt - it seems to have no affect on the operation of the AC system.... and, it doesent really work with the idler...???

John-----


Why the idler was used for big block cars with C-60, I do not know. However, if the idler pulley was used with the same belt used for cars without C-60, then the idler would serve no purpose, at all. It would essentially become an "ersatz tensioner" and no tensioner is necessary with the non-C-60 belt---it's a precise size to fit over the pullies and provide correct tension, as-is.

With the idler pulley arrangement, it's MUCH easier to install the belt since there is now a point of adjustment (i.e. the idler pulley). That may or may not have had something to do with the reason the idler was used. In fact, it's not a bad idea to install an idler pulley on a car without C-60 just to eliminate the PIA captive belt.

[John A.]

Re: C3 69 Pulley-Blues

Hey Joe,



Please take a look at the attached pictures. This is with the 990 belt from Quanta in place... seems there is a size discrepancy. Has anyone had this problem when trying to run the idler pulley configuration?