Dayco alternator belt difficulties

[Gary S.]

I just tried to install a Dayco belt for the alternator on my 72 LT1 without a/c. The belt appears to be the same length but the only way I can get it installed is to disconnect the alternator and slip the pulley into the loop of the Dayco belt. I am guessing that the original belt was narrower and fit down into the pulley grooves a bit deeper. The auto parts store has a belt that is 1" longer and I am going to try this.

Does anyone have a tried and true method for fitting new belts on our old cars? Does another brand fit better or truer?

Thanks.
Gary

[Joe L.]

Re: Dayco alternator belt difficulties

Gary----

Your assessment is correct; the original belt was a 3/8" wide belt and your Dayco replacement is likely of 7/16" width. The earlier belt does ride lower in the pulley, but that fact does not affect initial installation ease or difficulty.

The problem that you describe is a common one for 69-72 Corvettes with small blocks. The factory-specified belt length for many of these applications is a bit on the short side. Usually, a 1/2" or 1" longer belt will solve the problem nicely. It also puts the alternator a little further away from the exhaust manifold, which is another good thing.

[Joe L.]

Re: Dayco alternator belt difficulties

Gary----

Your assessment is correct; the original belt was a 3/8" wide belt and your Dayco replacement is likely of 7/16" width. The earlier belt does ride lower in the pulley, but that fact does not affect initial installation ease or difficulty.

The problem that you describe is a common one for 69-72 Corvettes with small blocks. The factory-specified belt length for many of these applications is a bit on the short side. Usually, a 1/2" or 1" longer belt will solve the problem nicely. It also puts the alternator a little further away from the exhaust manifold, which is another good thing.

[Gary S.]

Re: Dayco alternator belt difficulties

Thanks Joe.

[Gary S.]

Re: Dayco alternator belt difficulties

Thanks Joe.

[Patrick H.]

Re: Dayco alternator belt difficulties

Gary,

What size is the belt tht seems too short? Just curious.

Patrick

[Patrick H.]

Re: Dayco alternator belt difficulties

Gary,

What size is the belt tht seems too short? Just curious.

Patrick

[Gary S.]

Re: Dayco alternator belt difficulties

I bought a Dayco 52.5" belt, part number 15525, and traded it in for a 53.5" belt, part number 15535, and now it is a smidgen too big. It will probably work as long as I don't mind not having the belt as tight as I usually adjust it using the TLAR method (that looks about right). I will try a 53" tomorrow to see how it fits. The odd thing is that the 52.5" is actually a tad wider than the 53.5". It is only noticable when compared side by side with each other.
Reports to follow. I had similar problems when I had a 66 with a non-standard alternator bracket. I tried about four or five different belts before I had one that worked well.
Gary

[Gary S.]

Re: Dayco alternator belt difficulties

I bought a Dayco 52.5" belt, part number 15525, and traded it in for a 53.5" belt, part number 15535, and now it is a smidgen too big. It will probably work as long as I don't mind not having the belt as tight as I usually adjust it using the TLAR method (that looks about right). I will try a 53" tomorrow to see how it fits. The odd thing is that the 52.5" is actually a tad wider than the 53.5". It is only noticable when compared side by side with each other.
Reports to follow. I had similar problems when I had a 66 with a non-standard alternator bracket. I tried about four or five different belts before I had one that worked well.
Gary

[Patrick H.]

Re: Dayco alternator belt difficulties

Gary,

Based on my own observations, I would use the shorter one (52.5) unless you really like the 53. Why? No matter what, I always get this belt to squeak (above 3000 to 3500 rpm), and they often rub on the PS pump despite that nice little guard built into the PS pump. The shorter belt will likely stretch soon enough to work well, and it may work better to avoid the PS. Let me know that too, as I'll be trying my 3rd or 4th belt for my car soon. Mine is squealing again, and short of replacement I've never found a way to stop that.

Patrick

[Patrick H.]

Re: Dayco alternator belt difficulties

Gary,

Based on my own observations, I would use the shorter one (52.5) unless you really like the 53. Why? No matter what, I always get this belt to squeak (above 3000 to 3500 rpm), and they often rub on the PS pump despite that nice little guard built into the PS pump. The shorter belt will likely stretch soon enough to work well, and it may work better to avoid the PS. Let me know that too, as I'll be trying my 3rd or 4th belt for my car soon. Mine is squealing again, and short of replacement I've never found a way to stop that.

Patrick

[Clem Z.]

Re: Dayco alternator belt difficulties

"wrapped" belts are wider than "cut" belts of the same size. also the "wrapped" belts stay on better than cut belts. back in the 60s we used corvair belts on our corvettes so they would no come off at high engine RPM as they were "wrapped" belts and the stock corvette belts were "cut" belts. wrapped belts are now used on lawn mowers and are green in color and they work better than any thing for hi RPMs.

[Clem Z.]

Re: Dayco alternator belt difficulties

"wrapped" belts are wider than "cut" belts of the same size. also the "wrapped" belts stay on better than cut belts. back in the 60s we used corvair belts on our corvettes so they would no come off at high engine RPM as they were "wrapped" belts and the stock corvette belts were "cut" belts. wrapped belts are now used on lawn mowers and are green in color and they work better than any thing for hi RPMs.

[Gary S.]

Re: Dayco alternator belt difficulties

Patrick, as I mentioned in the original post the only way to get this 52.5" belt on is to totally remove the alternator, insert the pulley into the belt loop, reattach the alternator and snug it into place. When that is all done, there isn't any adjustment available. The adjusting bolt is at the beginning of the arc on the adjusting arm. Not a desirable situation.

As long as the parts house doesn't mind the multiple returns, I should have this installed today.
Gary

[Gary S.]

Re: Dayco alternator belt difficulties

Patrick, as I mentioned in the original post the only way to get this 52.5" belt on is to totally remove the alternator, insert the pulley into the belt loop, reattach the alternator and snug it into place. When that is all done, there isn't any adjustment available. The adjusting bolt is at the beginning of the arc on the adjusting arm. Not a desirable situation.

As long as the parts house doesn't mind the multiple returns, I should have this installed today.
Gary