66 L79 belt question. How many?

[Joe L.]

Re: No one would add a belt...

Gary------

That question I cannot answer.

However, keep in mind that it's possible that they are right. I doubt it, but it's a possibility.

The problem is that it's so difficult to ascertain what was originally done in a case like this. GM could say that 2 belts were used, many cars could be observed with 2 belts, it seems logical that there should be 2 belts if there are 2 grooves on both pullies, but that does not mean that 2 belts were actually installed on all cars or, even, any cars.

One thing to also keep in mind, though: the pulley system and pullies used for 1966 were the same as those used later models through, at least, 1970. In the case of those later models, I don't know of a case in which the same pulley system used for 1966 did not have a 2 belts. Still, that does not necessarily prove that 1966 had the 2 belts.

One other thing: the GM #3837810 belt that was used for the 1966 L-79 captive belt application was discontinued from SERVICE and replaced in September, 1974. So, the chances are that if you find a 1966 Corvette with L-79 and it has a GM #3837810 captive belt installed, then that belt was originally installed at St. Louis.

[Joe L.]

Re: Patrick; I think outside is where...

Gary------

Whether the captive belt is on the inside pulley groove (#1; closest to block) or the outside groove (#2), depends upon the installed alternator pulley. The pulley shown in the photos of the L-79 with the captive belt on the outside groove does not appear to me to be the correct pulley for 1966 with L-79 and without C-60 or N-40. GM says that the pulley used for 1966 L-79 without C-60 or N-40 is GM #3871242. That pulley, shown in the photo attached below, has an inboard, "built-in spacer". This "spacer" causes the alternator belt groove to align with the OUTER groove on 2 groove small block pulley systems. In that case, the captive belt would have to ride on the inboard pulley groove. By far and away, the inboard pulley groove is the groove generally used for captive belts.

However, was the GM #3871242 actually used for all, some or, even, any, 1966 Corvettes with L-79 and without C-60 and N-40? I don't know.

[Joe L.]

Re: 66 L79 belt question. How many?

Charlie-----

I don't know the answer from a design standpoint. However, I can say that the VAST majority of Corvette captive fan belt applications have the belt on the innermost (i.e. #1) groove. In fact, if the 1966 application had it on the outer groove, it's the only one I know of. I'm not saying that there might not be others, but it would be the only one I know of.

[Jean C.]

Re: 66 L79 belt question. How many?

Thanks Joe. I am certainly have no real knowledge of how the belts were configured or why they may have been configured as they were, but it seemed logical to me that the belt that is designed to be the "safety net" so to speak would be on the inside pulley. Probably no Theorem of Belt/Pulley Congiguration to support that idea. I'll leave it to you'll with more experience than I have to sort it out.
Best regards,
Charlie

[Patrick T.]

Here is my setup...

'67 L-79 no p/s, p/b or air. Notice the single piece black oxide pulley which is correct for my car and that the belt lines up with with the water pump and balancer pulley. If the belts were reversed, the alternator belt would not line up and probably fly off. I'm outta here! PT

[Joe L.]

Re: Here is my setup...

Patrick-----

I have not been able to determine which alternator pulley was used for 1967 with L-79 and without C-60 or N-40. However, the one you have looks like a GM #3909815. That pulley was supposed to be used for 1967 with 300 hp and, I suppose, it may have been used for 1967 with L-79, too, since I have not been able to confirm which pulley was used. The 3909815 could not have been used for 1966, though, inasmuch as I don't think that it was released in time for the 1966 model year. However, it's predecessor, GM #3843342, was used during the 1966 model year but, as far as I can tell, only for 300 hp engines. The GM #3843342 was configured very much like the 3909815.

[Jim S.]

Re: Jim,yes,but

Gary

While the photo leaves open for discussion which pulley the captive belt is on,it is obvious to me that at least some L79 had the captive belt.

I am 100% positive my captive belt was/is on the inside pulley. My alternator would not line up if it was reversed.

That being said, I would always take the point deduct for two belts as the captive belt is a real pain in the butt to install.

Thanks for the comments

Jim

[Brian K.]

Re: Here is my setup...

Joe, do you know the alternator pulley numbers for the 66 L79 with and without PS?

[Gary B.]

According to Micheal Hanson...

The correct pulley for '66 w/o PS or AC is the 3871242 that Joe also mentioned. With the thick offset of that pulley, the likely position for the alternator belt would be on the outside pulley track, leaving the inside pulley track available for the captive belt. So this would agree with the configuration on the engine being lowered into place in the photo from Noland's book. But this is inconsisten with setup that Patrick shows in his photo.

Gary

[Joe L.]

Re: According to Micheal Hanson...

Gary-----

However, Patrick's car is a 1967. I can't confirm that what was used for 1966 was also used for 1967. For some strange reason, GM is "silent" on what pulley was used for 1967 with L-79 and without C-60 or N-40.

Every-so-often, I have noted this "silent treatment" for certain components. From other situations, I think what it may mean is that "various" components were used so GM "doesn't want to commit itself".

It's also possible that some 1966 cars with L-79 and without C-60 or N-40 were built with different configurations. As I mentioned, it all depends upon what alternator pulley was used. If, for whatever reason, the "non-spaced" alternator pulley was used, then the captive belt would go in the outer groove. If the "spaced" alternator pulley was used, then the captive belt would go in the innermost groove. From a functional standpoint, either would work just fine. However, I do think that "officially" the "spaced" pulley, GM #3871242, was the one.

[Joe L.]

Re: Here is my setup...

Brian------

I believe that for "without power steering" it's the GM #3871242 that I have described and pictured previously in this thread.

For "with power steering", I believe it's the GM #3829387. This is a similar machined steel pulley, except that it is not "spaced". So, in this configuration, the alternator belt goes around the INNER pulley groove of the waterpump and balancer pullies and is adjusted at the alternator. The power steering drive goes around the OUTER pulley grooves on the waterpump, balancer, and power steering pump pullies and is adjusted at the power steering pump. There is no captive belt in this configuration.

[Philip C.]

Soild lifter 63.64.65 and 66 67 350 Hp used

two belts,(No opps) front gooves 66, 67. the spacer on alt was for A/C. Phil 8063

[Mark G.]

[Mark G.]

Re: C2 '66 SB Pulley Chart

This is what I have put together while searching for K19 parts and why the L79 puley setups were so complicated.

Mark #35760

[Mark G.]

Re: C2 '66 AMA Cooling Specifications

The lower portion of the page shows that two belts of different lengths were used on the '66 L79; "D" the alternator belt 54.00" and "E" the captive 34.40" some say 34.10" belt. Oddly, it does not show the K19 A.I.R. belt length.