'66 L79 Water Pump Pulley?
I bought a '66 L79 roadster about 6 years ago and am finally doing it. I DO NOT HAVE A JUDGING MANUAL FOR A '66 although I have 'em for some of my other cars!!!!! (seems like somebody's always got to say check your judging manual instead of answering a question) I've gotten conflicting opinions on what the water pump pulley should be and even the online sources aren't consistent. My '65's have idlers and a 2 groove upper. I'm aware the 66 doesn't have an idler. The upper pulley that was on the car when I bought it was single groove, but not deep like the lower is. IF there is supposed to be a double groove upper and captured inner belt as some have suggested then my alternator bracket is likely incorrect also. Help is appreciated.
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Re: '66 L79 Water Pump Pulley?
Norris------
What is the part number of the water pump pulley that's on the car now? It should be stamped on the face of the pulley. Also, what is the part number of the balancer pulley? Does the car have power steering,r a/c, or K-19?In Appreciation of John Hinckley -
Re: '66 L79 Water Pump Pulley?
Joe, it doesn't have AC, PS or K-19. I'll check the bottom pulley in a few. E Bay is full of single, deep groove pulleys with applications CLAIMING to be L79. The lower pulley is 2 groove deep. The upper was one groove BUT was not deep, so it's obviously been changed. It had an incorrect water pump with the big hole for the bypass fittings, so I've done that. The pulley I ordered off internet is stamped 3883234DR but now I'm wondering and it IS returnable. As always, thanks for the advice.Comment
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Re: '66 L79 Water Pump Pulley?
Joe, lower pulley is 3858533 BJ Upper that's was on car was 3905995 C? (may be an F). I've known this car for over 50 years but have only owned it for a little over 6 years. It's a factory L79 but original transmission is gone for unknown reasons. It has a '65 transmission with the smaller cluster gear shaft and the speedo drive WAS on the wrong side, but we changed the tail housing when we went through it. Rear appears to be original. An elderly couple, friends of my parents had it until about 25 years ago and I thought I was getting it then but it got sold to a neighbor of theirs who sold it to me in 2017. They weren't really car people and when anything needed doing it simply went to a local garage which wasn't by any means a Corvette specialist. Appears water pump, fan clutch and upper pulley were changed and it had a cheezy aftermarket radiator also. Alternator lines up perfectly with one groove pulley, so if it has a captured belt on water pump/lower pulley like big blocks it'll take a different alternator bracket or either one of those alternator pulleys that runs a spacer between the fan and pulley.Comment
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Re: '66 L79 Water Pump Pulley?
Norris------
You have the correct balancer pulley. The waterpump pulley is incorrect. In fact, as you have noted, it's a standard groove pulley. I'm surprised it even aligns with either groove on the balancer pulley. The 3905995 was not even released until the 1967 model year although I suppose it's possible it was used on very late, base engine 1966 models.
The correct waterpump pulley for your application is GM #3770245. This is a 2 deep groove pulley. Whether it originally had both belts factory-installed is a matter of some debate. Not with me, though; I think both belts (alternator and captive) were originally installed. A lot of cars "lost" the captive belt over the years due to the difficulty of installing it.
The GM #3883234 is a single groove waterpump "add-on" pulley. It was used in conjunction with another 2 groove waterpump pulley as an K-19 driver pulley. It is not used in your application and cannot be used without a primary, 2 groove waterpump pulley.In Appreciation of John HinckleyComment
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Re: '66 L79 Water Pump Pulley?
Norris,
In addition to what Joe said about ‘66 L79s losing their captive belt due to difficulty installing it, some L79s lost their captive belt because up until the 2005-2010 timeframe, the ‘66 national level judges did not believe a captive beat was used. Or they were told by the ‘66 Team Leader at the time to deduct for the presence of the captive belt. I’m sure they were going by the best information available at the time. Back around 2005, I spoke with the owner of a ‘66 no-option, L79 at the National whose car lacked the captive belt and he said he removed it so as not to get a deduction. The 5th and 6th (current) editions of the ‘66 JG call for the use of 2 belts for a no-option L79. Of course, one of those two belts is the captive belt.
Gary
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Re: '66 L79 Water Pump Pulley?
Thanks Joe and Gary for all the help. I think I've got this figured out now except for still a little skeptical of the alternator pulley I bought from my favorite supplier. I'm accustomed to seeing the machined deep groove pulleys on everything SHP both small and big block and this one is almost a dark grey color and the pulley and fan are one piece and I don't THINK it's wide groove, or "deep" as I've always called it. Their parts list shows it for both 300 and 350 horse and I've never seen that before either. This car wasn't supposed to go there. When we bought it I knew the history and it was like, "honey, we're gonna' put a new top on this and ride in it and not worry if we get caught out in a shower". The top made the interior look bad, so we did complete Al Knock. The interior made the weak paint look bad, so we stripped it and had it painted. Then the bumpers by Advanced Plating AND NOW we've dropped the chassis and going completely through the drive train. Geez, we'd have been better off to go to Mecum or BJ and buy one done.Comment
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Re: '66 L79 Water Pump Pulley?
Norris------
Assuming that the alternator pulley you bought is a GM piece, check it carefully for a GM part number. On pulley/fan assemblies like you describe, the part number is usually found stamped on the face of the pulley. Please post what you find.In Appreciation of John HinckleyComment
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