65 L78 Water Pump Belt
I am looking at a 1965 396/425HP. The water pump belt is supposed to be outboard of the alternator belt. This particular engine has that backward. Anyone have any experience making the switch? What components are potentially wrong? Car has original block.
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Re: 65 L78 Water Pump Belt
You are correct per page E350 of AIM for L78
Should not be a problem to flip them - be sure alternator pully lines up straight - this is assuming brackets and pully on alternator are correct
if the pullys and brackets are all stock then it should line up - the alternator belt should not be straight with the belts reversed -
Re: 65 L78 Water Pump Belt
If we're discussing a non-power steering car, sounds like the wrong lower alternator mounting bracket is installed; maybe the one off a '66, with the '810' casting, which has a high horizontal rib and a "droop" on the rear eyelet, and a vertical slope to the front, to place the alt. belt in the forward groove of the pulleys.
Stock 396 L78 has a straight arm -- top bracket in both pics. The lower bracket is probably from a '66 BB Chev or some other that has the droop arm but no forward slope. This bracket would work correctly for a '65 BB Corvette but would lose on configuration. Sorry, I don't have a '66 '810' bracket to show.
Other possibles; the alternator pulley (again, if no P.S.) does not have the correct offset for the groove (should be a '387' pulley).
m
aComment
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Re: 65 L78 Water Pump Belt
The 810 bracket for a 427 is on top with the L-78 bracket below. You can see that the alternator is located over the forward pulley groove with the 810 bracket.
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Re: 65 L78 Water Pump Belt
Looking at the water pump belt there does not seem to be any adjustment. How do you get this belt off and on?
Thanks for the help!Comment
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Re: 65 L78 Water Pump Belt
Back off the top alternator brace and slack that belt. Probably easier to remove the crank pulley 3 bolts (not sure that just loosening is enough) to remove the lower pulley, then slide the w.p. belt out of the forward groove.
[alternate] Would probably work by removing the water pump pulley (again, not sure that loosening is enough), but you have the weight and awkwardness off the fan assy to deal with.
You're right, there is no adjustment, so you have to remove one or the other pulley to install in the groove. The original w.p. belt was really taut as installed, and the current GM replacement is longer (ie. sloppier fit, up to 1_1/2" displacement at the middle of the stretch). You can order the tight one as a repro, though.Comment
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Re: 65 L78 Water Pump Belt
Both ways Wayne suggests will work
I have always found it easier to pull the water pump pulley - If belt is correct you will not install it by loosening the pulley.
Be carefull about selecting a belt which is too loose. Should you toss the belt at higher RPM you might take out the fan and do other damage this was why back in the day we would leave the belt off when at the strip !Comment
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Re: 65 L78 Water Pump Belt
I had the same problem with my '66 BB w/o PS. It had the '65 bracket putting the w/p belt in the wrong groove - just the opposite to your problem. I got my belt on by loosening the crank pulley and slipping the belt on the pulley and then slowly tightening the 3-bolts to pull the pulley in place thus tightening the belt at the same time. FWIW, I got my restoration belts at Quanta and they offer a long and short version of what you want. From what I remember, there is very little differences in the belt lengths between the short & long version - maybe +/-3/8".Comment
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Re: 65 L78 Water Pump Belt
On my 65 L78 I found the easiest way to replace the belt was remove the fan and water pump pulley.
Insert a temporary stud (old bolt with head cut off) into the water pulley mounting boss. Slide the pulley with both belts fitted onto the water pump boss. Place the fan onto the water pump, sliding over the stud, then line up and insert two bolts either side of the stud and tighten. Remove the stud and insert the remaining two bolts.
Cheers,
GaryComment
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