Tensioner and Belts beware...

[Ccmano]

So as part of the current winter project with items too numerous to detail, I changed the serpentine belt on the Z recently. Looking at various sources the recommended belt is 80.5 inches long. Available from various manufacturers and sources. I purchased a Duralast from Autozone. When I started the car afterwards I instantly noticed the tensioner making a rattling noise. Even got squealing when the A/C compressor kicked in. I thought, crap! You do one thing and something else goes wrong. Knowing that tensioners can be rebuilt I looked up the thread here in the forum, bought the parts and rebuilt the tensioner. From the looks of the inside it needed it. Excellent info as always. Here’s the link.

http://www.zr1.net/forum/showthread....ight=Tensioner

Something in the back of my mind reminded me there was a belt issue as well. I started searching and sure enough. There are several past threads on the matter which seems to come up every few years. Here’s one.

http://www.zr1.net/forum/showthread....erpentine+belt

Seems the standard quoted replacement belt length is 80.5 inches. Why, no one knows. The original belt measures 80.1969 inches. Belts are available in 80, 80.2, 80.25 and 80.5 inches. Apparently the much quoted Marc Haibeck recommends 80 inch belt to tighten things up a bit more. So I took his advice and purchased an 80 inch belt Dayco 5060800. After installation I must say there is a significant difference in the tensioner position. I have posted some pictures below.

My take away is this. If you have a weak tensioner, the 80.5 inch belt will show it quickly. The 80 inch belt may save you a tensioner rebuild for at least a while. On a side note there is also an alternator pulley diameter question that plays into this. Apparently replacement alternators have some variation.
H


80.0 inch belt


80.5 inch belt

[Paul Workman]

Originally Posted by Ccmano

So as part of the current winter project with items too numerous to detail, I changed the serpentine belt on the Z recently. Looking at various sources the recommended belt is 80.5 inches long. Available from various manufacturers and sources. I purchased a Duralast from Autozone. When I started the car afterwards I instantly noticed the tensioner making a rattling noise. Even got squealing when the A/C compressor kicked in. I thought, crap! You do one thing and something else goes wrong. Knowing that tensioners can be rebuilt I looked up the thread here in the forum, bought the parts and rebuilt the tensioner. From the looks of the inside it needed it. Excellent info as always. Here’s the link.

http://www.zr1.net/forum/showthread....ight=Tensioner

Something in the back of my mind reminded me there was a belt issue as well. I started searching and sure enough. There are several past threads on the matter which seems to come up every few years. Here’s one.

http://www.zr1.net/forum/showthread....erpentine+belt

Seems the standard quoted replacement belt length is 80.5 inches. Why, no one knows. The original belt measures 80.1969 inches. Belts are available in 80, 80.2, 80.25 and 80.5 inches. Apparently the much quoted Marc Haibeck recommends 80 inch belt to tighten things up a bit more. So I took his advice and purchased an 80 inch belt Dayco 5060800. After installation I must say there is a significant difference in the tensioner position. I have posted some pictures below.

My take away is this. If you have a weak tensioner, the 80.5 inch belt will show it quickly. The 80 inch belt may save you a tensioner rebuild for at least a while. On a side note there is also an alternator pulley diameter question that plays into this. Apparently replacement alternators have some variation.
H



80.5 inch belt



80.0 inch belt

Good 2 know. Thanks 4 the pix!

[PhillipsLT5]

Great info

[billschroeder5842]

Thanks- who would have thought that .5 inch would make that much difference.

[WARP TEN]

Originally Posted by billschroeder5842

Thanks- who would have thought that .5 inch would make that much difference.

I don't find that so surprising, Bill--After all, someone once said that size matters --Bob