66 L79 No Power Belts

[Greg T.]

After checking all the archives I'm afraid I have to ask a belt question. I have a 66 L79 with no power. I have the 533 crank pulley and 245 WP pulley. When I install the captive belt 3837810 (34.40 inches) I have 1 1/2 inches of play in the belt. Is that right?

My alternator belt is 3861946 (54.00 inches). That belt is too short. The slot in the adjustment bracket is about 1/2 too short. The alternator pulley is a 3 5/8 deep groove PN 3871242. Everything lines up great.

Anyone else who has had this problem and know of a fix let me know. This car is to be judged. Thanks All

[Rob A.]

Re: 66 L79 No Power Belts

Greg,

My understanding is that a '66 L79(I have one) had a two groove water pump pulley and two groove balancer pulley. One belt only was used in the 1st groove of each of them and connected to the alternator pulley as well. You would only need an additional belt(s) for power steering, a/c, and an a.i.r. system.

[Gary B.]

'66 L79 No Power captive belt

Greg,

As you correctly state, you should have two belts in your '66 L79 with no power options. I have the same set up with my no power, '66 L79. I hope this 2-belt arrangment will eventually get corrected in the '66 TIM&JG. As of the 4th edition, the TIM&JG implies there was only 1 belt for no power L79 cars, but this is incorrect according to a number of owners of '66 no power L79 cars.

Your 533 crank pulley and your 245 WP pulley have the same part numbers as mine, so I assume your pulleys are correct. I just measured my captive belt and it is 34.4" when measured around the OD. Is that how you are measuring yours? My belts and pulleys are off the car, but there was NOT 1.5" of slop in my captive belt when it was on the car. I know I would have remembered if it had 1.5" of play and it didn't. I was quite snug.

Gary

[Greg T.]

Re: '66 L79 No Power captive belt

My belt is 34.40 inches long. I see that Long Island Corvette offers a short version of this belt. I'll call them tomorrow to see what they know.

[Rob A.]

Re: '66 L79 No Power captive belt

Gary,

I guess this error in JM info is the same as the missconception that a special add-on pulley is required if power steering is added. No additional pulley is needed, since the balancer pulley has 2 grooves. Funny thing is the assembly manual also calls for a single belt application for a no power setup.

[Rob A.]

Re: '66 L79 No Power captive belt

Greg,

I checked the archives and see the 2 belt configuration you describe is considered correct. Evidentally Noland Adams' book happens to show a good picture of a '66 (no power option) L79 with the 2 belt configuration.

[Peter L.]

Re: 66 L79 No Power Belts

Greg - Sounds like an original '66 L79 as far as the pulleys are concerned. Hope you'll keep it that way. The olde L79 belt or belts saga unfortunately has not been resolved in the '66 TIM&JG. Information in the TIM&JG is based on the BELT ROUTING, UPC 6, Sheet A4 in the 1966 Corvette Assembly Instructions Manual (AIM) which titled V-8 Engines 327. The interpretation is that UPC 6, Sheet A4 applies to "all" 327 engines, i.e. base engine and L79. Unfortunately, the only call out under the 327 Sp. High Perf Contents, UPC L79, Sheet A1 that references anything that might differ from the base engine is the crankshaft pulley, i.e PULLEY 3858533, that is a 2 groove pulley; but no L79 engine belts are called out in the AIM and the Parts Catalog only adds to the confusion. But if one adds to that the fact that the AIM calls out a 2 groove pulley (and we have numerous "original" examples of both '66 and '67 L79 Corvette engines and that all "basic" (no option) 327 Special High Performance engines up to 1966 and beyond have had "captive" or "idler" belts connecting the H2O pump pulley to the crankshaft pulley, leads one to at least be curious as to the reason for the AIM call out for the 2 groove crankshaft pulley. Several folks have posted on the DB that in fact the 2 groove pulley had a purpose otherwise GM would not have spent the time or money to install it.

Bottomline is base motor '66 Corvettes with not options had one belt (I've got one) while '66 L79 engine Corvettes with no options came from the General with 2 belts (I've seen too many original L79 no option engines for ones with two belts to be deviations from the mean), one being a "captive" belt that connected the H2O pump pulley and the crankshaft pulley.

BTW, you might double check with LICS on the alternator belt. I'm wondering it you didn't end up with the one for the base motor. Good luck.

Pete

[Michael H.]

Re: 66 L79 No Power Belts

I agree Peter. Add to that list a totally original 66 350 HP, VIN # 6596, purchased in 1980 from the original owner, that still had BOTH of it's original belts (and hoses, battery cables etc etc) The original idler belt was a 3837810.

[Michael H.]

66 Parts Book Scan

1966 printing of the parts book shows the 3837810 belt as used on the 327 350 HP with no other belt driven options. The length, 37 13/32", is slightly longer than the 37 3/8" shown in a 1974 printing.

[Gary B.]

Michael: You mean 34&13/32", not 37&13/32" *NM*

[Michael H.]

Re: Michael: You mean 34&13/32", not 37&13/32"

Yes, thanks Gary. Should have been 34 13/32", Not 37 13/32". I was typing faster than I was thinking, again.

[Greg T.]

Re: Michael: You mean 34&13/32", not 37&13/32"

Well I calculated that the right belt is about .2 inches too long. Long Island Corvette sells one that is .2 inches shorter. The guy didn't know why they had it. The engine has been line bored but it can't have moved it that much. I have some extra correct pulleys I'll try. I'm still stuck with the alternator belt being too short (54 inches). That really confuses me. I have the right exhaust manifold and alternator. Arggggg There is a big block alternator belt that is 56 inches long. I've ordered that. It should fit fine. Thanks to all.