1969 350/350 Pulley/Belt Combination
Joe has provided invaluable information on the belts and pulleys for a L-46. I would like to summarize the the belts and pulleys as installed with , I hope the last issue. Crankshaft Pulley is 3858533, AIR Pulley is 3932458, Water Pump Pulley is 3848904, pulley on Crankshaft for AIR is 3883235 and Alternator Pulley is 3909817 (with a 7 stamped on center of pulley). Belt for Water Pump and Crank is 3935420. Belt to AIR is 3881872. Belt to Alternator is PROBLEM. The belt I am using is 3959166 and the Alternator moves all the way to the end of the adjustment and does not seen to be tight enough. Any comments or suggestion to help resolve this last issue would be greatly appreciated. Steve Morrow
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Re: 1969 350/350 Pulley/Belt Combination
Steve------
This car does not have C-60, does it? If it does not have C-60, you don't have the correct alternator pulley. It should be a GM #1970831. This is a machined steel pulley of 3-3/32" OD and 1/2" groove (i.e. deep groove). It was discontinued in November, 1984 and replaced by GM #3844100 which is also now discontinued. The 3844100 is 1/64" larger in OD but otherwise the same. Neither pulley has a stamped part number. Reproductions are available for the 3844100 and, possibly, for the 1970831.
Your existing GM #3909817 is a 2-21/32" OD stamped steel pulley with integral fan. It has a 3/8" groove (i.e. standard or non deep groove). Standard groove pulleys are rarely used in pulley sets that are otherwise deep-groove and your application, unless you have C-60, is otherwise deep groove. Your fan belt should be 53-1/4" and I expect that if you have the alternator pulley right, your fan belt fitment problem will go away.
By the way, if you get the correct alternator pulley you will also need the separate alternator fan. That would be either a GM #3843346 if an early 1969 or a GM #1966990 if a later. Both GM discontinued in 1971.In Appreciation of John Hinckley -
Re: 1969 350/350 Pulley/Belt Combination
I really appreciate the time you have spend helping me get this right. No the car does not have C-60. The fan belt is 54 1/2 inches long as you indicated. There are plenty of 'new' pulleys on eBay. Will probably look around for an original to refinish. I have several fans that look like the fan you posted in the past with the 'small tooth' on the large fin and zinc plated. Thanks Again SteveComment
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Re: 1969 350/350 Pulley/Belt Combination
Steve,
If you use the search function you will find many threads on this subject. The 3959166 is too long as you have discovered. The 1971 Alt belt 3847704 is 52 3/4 inches. On my 1969 non A/C L-46 w/PS it put the Alt in the middle of it's adjustment range. I believe the belt size info came from Joe Lucia in a post about 1971 LT-1 belts. Can't thank Joe enough for all the help he has given on this board. You can get the belt from Quanta or Paragon. Probably other vendors also have it, however I believe all the restoration belts are made by Quanta.Larry
2002 Z51 Convertible
1969 L46 ConvertibleComment
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Re: 1969 350/350 Pulley/Belt Combination
Joe,
Sorry about the confusion on belt length. I used the length of the belt that I was using and was also pointed out by Larry above. He suggested a 3847704 as an appropriate belt. Is this what your information shows? Appreciate both Joe and Larry responding.Comment
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Re: 1969 350/350 Pulley/Belt Combination
Steve------
One of 2 belts were originally used for the alternator belt for the 1969 L-46 without A/C application. One was GM #3847704. I don't have a length on this belt. It was released in 1964 and discontinued from SERVICE in February, 1967 and replaced by GM #3847702. The latter was 52-1/2" X 3/8". It's possible, though, that the 3847704 continued to be used in PRODUCTION after 1967.
The other possible belt was GM #3885047. This belt was 53-1/4" X 3/8".
By the way, the GM #3847702 was discontinued from SERVICE in July, 1970 and replaced by GM #3932330. The latter is a cogged belt of 52-1/4" X 3/8".In Appreciation of John HinckleyComment
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