I have a 65 L76 that was fitted with a GM, stock appearing PS unit (also refitted with the "5 qt" pan to permit this install) prior to my purchase of the car. (Seemed like a sin to me, but now I kinda like the PS). The engine also came to me with a Vintage Air system on it, since removed by me - this required some re-jiggering of the pulley and belts set up since I took a compressor out of the equation. I have also replaced the alternator since buying the car. To set it up, pulley-wise, I basically mirrored the configuration (or what I think the configuration would be) of a 65 L79 with PS. But the pulleys do not seem to be perfectly lined up when the belts are on (mostly in the area of the alt pulley lining up with the crank pulley - but maybe I am being too anal?), so I am going to ask the experts: could you please identify by GM part # the correct pulleys for this configuration - the PS pulley, the main pulley and the alt pulley? It runs just fine and hasn't slung a belt yet, but I don't care for a hard-learned lesson (again, in a long line of such things). Thanks for your help, as always.
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65 MM Convertible, L76 (365 hp) -
pretty please? *NM*
65 MM Convertible, L76 (365 hp) -
Re: pretty please?
Jack,
The L79 w/PS was a later offering on a late introduction engine option. Alternator flipped to the driver side in 66. So not a lot of 65 L79's w/PS were out there and you see a range of opinions on what was original.
Your question is easier as you just want it to fit. You should have crank pulley 3858533 (maybe stamped 3766987) and pump pulley 3770245 from the original L76. Both are deep groove design with two grooves. You would also have the cast iron 3834720 single grove P/S pulley if you want to copy the L79.
Joe Lucia is the last word in part numbers and current availability. These are all in reproduction if no longer available from GM.
Without P/S, the alternator belt ran in the front track. With P/S, on the L79 only, this moved to the rear track. Alternator pulley 3829387 was specified. By itself, this does not quite line up. The '65 assembly manual shows a small spacer was added in front of the alternator casing and a correspondingly shorter spacer was used to the rear. I could not find these in reproduction but found them simple to fabricate. This brings the alternator further to the rear and in line with the rest of the drive. Of course the alternator brace was now a bit off. I couldn't bring myself to tweak the original so bought a repo to alter.
Side note, the repo is punched out of 0.250 stock, thicker than my 0.20 original which has an effect on the offset bends. Turned out, dead flat fit the altered spacing perfectly.
Be sure your lower rad hose is positioned well away from the belt that is now tucked much closer to the inside of the bend by the pump. Belts and hoses do not mix well in operation.
More often than not you cascade a bunch of unforseen changes when you want to re-engineer something different than what the good General intended. For some, that can be fun too.Comment
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Re: pretty please?
Thanks Chris, you have really helped me on this, much more info than I was able to gather from the TIM&JG, other sources, etc. - BTW, My first thought was to just run the PS belt in the same manner as the idler pulley belt found on the L76, keeping everything else pure L76, but the PS pulley selection never resulted in a perfect line up down there (unless someone can shed some light on that idea) so I have defaulted to this L79-style idea.
Of course, I could just remove the PS and return to a true 65 L76 setup (I sourced a big "6 qt" pan in case I want to go that route), the PS and the 65 BB hood are the only things not original or correct on the car (ok, and the side pipes) - as for the hood, I have toyed with the idea of planting a story that there was this SB hood shortage at the plant in late March of 1965 . . . .65 MM Convertible, L76 (365 hp)Comment
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Re: pretty please?
Chris, Jack sent me over here to read about the pulley setup as well, since I have the same issues he had. The only thing I missed (or didn't get into my skull) was where the PS belt runs. Does it run on the outer crank pulley groove, both crank and water pump pulley outer grooves, or is there a separate crank pulley for the P/S belt like the low hp cars? Thanks, PaulComment
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Re: pretty please?
I found a couple of other P/S posts that seem to have answered my question. Thanks.Comment
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