Belt tensioner question

[Corvette95]

Originally Posted by Dynomite

Belt is too long

I have double checked the part # . Plus the tensioner was jumping with old belt, that is why I sent the tensioner for rebuild. I need to make sure the pulley is correct on the alternator at this point. It is 2.4 inches across.

[secondchance]

For what it?s worth, GM OEM belt, I believe, was 80.375?. When new, these belts required walking the starter to install because they were so tight. Some replacements are 80.5? and would slip on while tensioner is held down. Not all, but a lot of fan belts? part number indicates length. xxx805 would mean 80.5? for example.
What brand fan belt are you running?

I had a similar issue and eventually figured out alternator I replaced had L98 pulley. Replacing the pulley solved the issue. Since then I went with high output hair pin alternator with 2.2? pulley. This meant going to 80? belt.

For some reason apostrophes and inch symbols are showing up as question marks. Weird...

[Corvette95]

So I put a 3/4 inch smaller belt on it. Had to bump the motor to get it on. I don?t think there is an undersized pulley on it. The tensioner way heavy loaded with smaller belt, it still shook but no noise from tensioner. There is however, some minor noise from the metal fans of the alternator hitting the pulley or something, just ?barely? . So I know I will have to replace alternator (please tell me the quickest way to do this with plenum on, I read the factory manual way that says pull the water pump pulley and oil sender , but even after this , I am not going to leave the smaller belt on it because I think it is much too tight. Thoughts?? I measured the pulley and it seems to be stock size at 2.4 inches. For what it is worth I put a Gates K060795 Outside Length (mm): 2034mm

[A26B]

Originally Posted by Corvette95

I have double checked the part # . Plus the tensioner was jumping with old belt, that is why I sent the tensioner for rebuild. I need to make sure the pulley is correct on the alternator at this point. It is 2.4 inches across.

Stock Alternator Pulley Dimensions

[Corvette95]

Thanks Jerry, mine measures 61 mm across. I don't know if that is the L98 pulley or not, but got to replace the alternator. I will make sure the new one is to these specs and put the A/C Delco belt back on. I only drove this car ten miles before I started the restoration.

[Corvette95]

If my current alternator nor the new alternator comes with the spacer bushing, where can I get one and what is the size? I am figuring the one that is on the car is missing the spacer which is why the fins are lightly scraping the case.

[Jagdpanzer]

What is idle RPM?
Appears in the video to be low.
Try increasing the RPM to see if it improves things.


Sent from my iPhone using ZR-1 Net Registry

[Corvette95]

This was a quick start up check for oil/fuel/coolant leaks (hasn't been started since mid January). I had not set the idle or adjust TPS yet, the idle is off but that was to be expected. The tensioner still rattled at higher rpm until I put the smaller belt on it. I am going to replace the alternator because I believe it doesn't have a spacer and the fins are lightly rubbing plus the pulley seems to be about 20mm too small. I just hope the new alternator has the spacer. I guess the rpm was around 800 but it did drop with a/c cycle. Dash and interior is still out so no gauges. Goes to the paint shop when I get the motor together so it can be moved around. Thanks

[Flyman 27]

Working on my alt as well. My fan was rattling as well. Turned out to be the fan barely nicking the intake, just enough to ring like a bell.
Installed a spacer behind the fan to reposition it a little and now it misses.

[Corvette95]

Originally Posted by Flyman 27

Working on my alt as well. My fan was rattling as well. Turned out to be the fan barely nicking the intake, just enough to ring like a bell.
Installed a spacer behind the fan to reposition it a little and now it misses.

What spacer did you use if you did not have the OE one?