66 big block L72
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Advanced
Joined: Mar 2018
Posts: 80
Likes: 8
From: oakdale ca
66 big block L72
I've got a question, I must be missing something, I took the engine out and had it completely rebuilt, everything new except
I kept the block, thought since I had the engine out I would buy new belts and hoses, I got the engine back from the rebuilder
and installed it myself over this past weekend, everything went fine, except for the belt closest to the block, this car has no
power steering, a/c, and is heater delete, only 2 belts, the belt closest to the block just goes around the crank pulley and the
water pump pulley, the other belt goes from the crank pulley over the top of the water pump pulley and to the alternator, how
do you put some tension on the inner belt, by the time you get it over the water pump pulley it's loose, I can't believe the alternator
belt can turn the water pump with only 90 degrees of contact. What have I missed????
I kept the block, thought since I had the engine out I would buy new belts and hoses, I got the engine back from the rebuilder
and installed it myself over this past weekend, everything went fine, except for the belt closest to the block, this car has no
power steering, a/c, and is heater delete, only 2 belts, the belt closest to the block just goes around the crank pulley and the
water pump pulley, the other belt goes from the crank pulley over the top of the water pump pulley and to the alternator, how
do you put some tension on the inner belt, by the time you get it over the water pump pulley it's loose, I can't believe the alternator
belt can turn the water pump with only 90 degrees of contact. What have I missed????
Drifting
Joined: Sep 1999
Posts: 1,417
Likes: 161
From: Des Moines, Iowa, USA Iowa
This question comes up frequently, and the problem relates to the which belt you use and which pulley you have. If you have an original (rare) 680 water pump pulley then the belt you need is the Quanta 3837810SV (short version) also known as 29-B-084B at www.gastanks.com with the other option being the 3837810LV (long version) which typically fits cars with repro water pump pulleys. There is only 1/4" difference between the two belts in length but that makes all the difference in the fit. Previously I recall that Long Island acutally would sell you both belts, you use the one that fits and send the other one back. I don't know if they still do that. Anyway, the Quanta belts are the best option for fitment 
Last edited by Velox; Jun 17, 2019 at 08:12 PM.
Thread Starter
Advanced
Joined: Mar 2018
Posts: 80
Likes: 8
From: oakdale ca
well the belt I bought is 35.125 inch circumference and it was a struggle to get it over the water pump pulley and now it appears kind of loose, the
Napa store said the belt for my car should be 35.62 inch circumference, but that 1 was way to big, I think it a pretty poor design not to a least have
a idler pulley to provide some amount of tension.
Napa store said the belt for my car should be 35.62 inch circumference, but that 1 was way to big, I think it a pretty poor design not to a least have
a idler pulley to provide some amount of tension.
Drifting
Joined: Sep 1999
Posts: 1,417
Likes: 161
From: Des Moines, Iowa, USA Iowa
well the belt I bought is 35.125 inch circumference and it was a struggle to get it over the water pump pulley and now it appears kind of loose, the
Napa store said the belt for my car should be 35.62 inch circumference, but that 1 was way to big, I think it a pretty poor design not to a least have
a idler pulley to provide some amount of tension.
Napa store said the belt for my car should be 35.62 inch circumference, but that 1 was way to big, I think it a pretty poor design not to a least have
a idler pulley to provide some amount of tension.
Safety Car
Joined: May 2007
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From: Indiana
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I just did this also. Most aftermarket belts are too wide, so it doesn’t fit down in the pulley like the original. Easiest way to to install the belt on the bottom pulley first, line the bolt holes on the pulley and the water pump as close as you can, then roll the top pulley with the belt on it, onto the water pump shaft. Tilt the bottom of the pulley close to the pump and then roll it on.
Last edited by Geralds57; Jun 17, 2019 at 08:49 PM.
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Joined: Sep 2010
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From: Southern Illinois
I've got a question, I must be missing something, I took the engine out and had it completely rebuilt, everything new except
I kept the block, thought since I had the engine out I would buy new belts and hoses, I got the engine back from the rebuilder
and installed it myself over this past weekend, everything went fine, except for the belt closest to the block, this car has no
power steering, a/c, and is heater delete, only 2 belts, the belt closest to the block just goes around the crank pulley and the
water pump pulley, the other belt goes from the crank pulley over the top of the water pump pulley and to the alternator, how
do you put some tension on the inner belt, by the time you get it over the water pump pulley it's loose, I can't believe the alternator
belt can turn the water pump with only 90 degrees of contact. What have I missed????
I kept the block, thought since I had the engine out I would buy new belts and hoses, I got the engine back from the rebuilder
and installed it myself over this past weekend, everything went fine, except for the belt closest to the block, this car has no
power steering, a/c, and is heater delete, only 2 belts, the belt closest to the block just goes around the crank pulley and the
water pump pulley, the other belt goes from the crank pulley over the top of the water pump pulley and to the alternator, how
do you put some tension on the inner belt, by the time you get it over the water pump pulley it's loose, I can't believe the alternator
belt can turn the water pump with only 90 degrees of contact. What have I missed????