Drive belts

[secondchance]

I am having an issue with drive belts being too long causing tensioner to bottom out resulting in rattling at idle. I tried AC Delco and Dayco. Both slip on too easy. Anyone know of shorter drive belt?

[Dynomite]

I am having an issue with drive belts being too long causing tensioner to bottom out resulting in rattling at idle. I tried AC Delco and Dayco. Both slip on too easy. Anyone know of shorter drive belt?

Remove your Belt and measure you belt length by holding the belt and tape measure in your hand and pulling the belt with tape on outside of belt through your fingers until you get to the mark you started on. I forget the lengths but I have NO standard length belt on any of my Zs. Anyway......for you......try a belt about a 1/4 inch or 3/8 inch shorter. Go to the counter at Autoparts with your belt and ask for the length you think will work from your measurements. And....when at the Autoparts (take your Tape Measure with you), measure the Belt they find to make sure of its length. You can also take the belt you now have with you and compare. Most Autoparts (I use Oreillys) will have Belts in lengths of 1/4 - 1/2 inch longer or shorter.

See Item #1 Alternator, AC Pump, Power Steering Pump (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-5.html#post1581825220)

[George Maz]

Marc just yesterday found same problem with a car I sent him.
"Before test driving the car we noticed a clicking sound from the accessory belt tensioner. It was bouncing against the retracted travel stop. It was acting like the accessory belt was too long. The engine has a new OE size Dayco belt. The problem as that the alternator pulley was too small. 2.2" diameter. The correct pulley is 2.6". We installed the correct pulley and now the belt fits normally."
...perhaps it's worth checking.

[secondchance]

Marc just yesterday found same problem with a car I sent him.
"Before test driving the car we noticed a clicking sound from the accessory belt tensioner. It was bouncing against the retracted travel stop. It was acting like the accessory belt was too long. The engine has a new OE size Dayco belt. The problem as that the alternator pulley was too small. 2.2" diameter. The correct pulley is 2.6". We installed the correct pulley and now the belt fits normally."
...perhaps it's worth checking.

I sent an email to Marc and he replied with the same info. Yes. I confirmed my alternator pulley is 2.2" diameter also. I'll be replacing my pulley with an aluminum billet piece I had been too lazy to install.

Also, learned another interesting info - Dayco belt model/length. Evidently correct LT5 belt is 5060805. Last 3 digits signify that it's 80.5" long. Next size down id 5060800 - 80.0" long. Evidently belts are available in .5" increments as Dynomite replied earlier.

[secondchance]

George,

Did Marc remove the pulley with the alternator on the car?

[Scrrem]

Yun,
I remember when I took my alternator apart, the nut on that thing was torqued pretty good....was a real bear to get loose. As I recalled I rigged up something to hold the fan blades and got a big socket with a breaker bar.
Rich

[Tony Davila]

Impact wrench will break it loose easy while on the car.

[George Maz]

George,

Did Marc remove the pulley with the alternator on the car?
He didn't mention.
There's a list of things to be sorted on this car first, then hopefully we can modify & tune as planned.

[secondchance]

While at Dempsey's Evolution Motorsport last Saturday, removed the alternator nut with an electric impact and installed correct diameter alternator pulley. However, the belt was still too long and allowing the tensioner to bottom out at idle. I replaced 80.5" belt with 80" and all is well. Looks like my Z lost 1/2" somehow... Actually, 80" belt went on easier than standard AC Delco belt I remember putting on a few years ago. Strange...

[Z51JEFF]

2 differant size pulleys is something I've never heard of before. Is it possable because there might be 2 differant size pulleys there could be 2 different size belts for an LT5? The reason I ask this is because years ago I tried replacing the belt with an OEM GM belt,correct part number and it would not go on regardles of what I tried,the belt was too short.

[secondchance]

2 differant size pulleys is something I've never heard of before. Is it possable because there might be 2 differant size pulleys there could be 2 different size belts for an LT5? The reason I ask this is because years ago I tried replacing the belt with an OEM GM belt,correct part number and it would not go on regardles of what I tried,the belt was too short.

Two different pulleys as in - smaller diameter for L98 (max. rev was 5,000 or 5,500?) and larger diameter for LT5 (7,000). Not two different pulleys for LT5s.
I too experienced OEM GM belt being very tough to install. Used a screw driver to get one side over the power steering pulley and craking the starter to completely slip it over. Seems, since then, belt manufacturers overcame complaints by going to 80.5" - just my suspicion.