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While removing the v-belts I discovered that I could not remove the alternator belt without removing the bottom bolt from the bracket.
The alternator hit the valve cover before the belt got slack enough to pull off the pulley.
I tried a new, correct length belt, only to discover that the belt that was on the car was the correct length.
I've tried two longer belts and they are still too short, and the longer of the two runs out of adjustment on the arm.
The arm and alternator pulley/fan are both chrome so they have been replaced at some point in the past.
Can anyone tell me the correct diameter of the alternator pulley and length of the alternator adjusting arm?
Been awhile But I rem having to remove my Moroso tall valvecover with the stock bracket for my 77, can't rem if I did with the new one as I only used it a bit before I tore it down.
There is no "correct length" 0n 50 year old cars that have changes. You can run a tape measure around the pulley's and get an approx. length. Then you get the correct angle to ride down inside the pulley. If you have a lower rpm motor You can run a smaller alternator pulley. taller valve covers and larger alternaters do cause problems
As per "Correct" belt. seems a lot of people find the so called "Correct" belt makes it very difficult to remove the power steering cap as well as the issue you outlined.
I find on my 77 that a 11A1385 belt works great.
If you don't need taller valve covers to, ahem, cover valves/rockers, you can solve this problem by going back to the stock valve covers.
My 79 had this problem, and these stupid valve covers, which I got rid of in favor of a set of GM Corporate Blue valve covers, with patina. Now to get rid of the rest of the chrome.
There is no "correct length" 0n 50 year old cars that have changes. You can run a tape measure around the pulley's and get an approx. length. Then you get the correct angle to ride down inside the pulley. If you have a lower rpm motor You can run a smaller alternator pulley. taller valve covers and larger alternaters do cause problems
Thank you, I misspoke.
I should have said "original factory pulley size".
I'd like to know the diameter of the original factory alternator pulley and length of the original factory alternator adjusting arm for a 1976 L48 w. AC.
I am considering installing factory stamped steel valve covers.
I have L82 valve covers on my 77 with A/C and have the same problem with belt.
1976 with A/C - 1977 early and some later 1977 with A/C used the same 61 amp alternator for both the L48 & L82.
Alternator number is 1102474
Here is the pulley size off of a 1102474 alternator.
1975-1982 Except 70 amp alternator used the same 11" large curved upper brace.
GM #460754
You can see the shape if you do a e-bay search using the number above.
While checking a couple of alternators here I measured the pulley dia. @ 2.804"
I was thinking that all I needed was about 1/4" smaller to get the belt to slip over it.
If you have taller valve covers than the original tin covers you will still have the same problem even with the correct pulley.
You just cant push the alternator far enough without hitting valve cover, period....
C/L of alternator is still the center line no matter the diameter of the pulley...
The best fitting belt I have found for the original pulley size is the Dayco 15535.
You can still find them made in the USA...
Belts I have tried...
Gates 7530 53.82 Snug
Gates 7535 54.33 Long
Dayco 15535 54.07 Best Fit.
Have you looked under the valvs covers? Generally speaking people have to put on taller valve covers because after market roller rocker arms are physically bigger.
Alternators have a red line rpm. Let's just say 17000 rpm.🙂 just for example that you have a 8 inch crankshaft pulley and 2.6 inch alternator pulley
Correct Alternator Pulley Size?
