1968 L89 Belt Squeal

[William H.]

1968 L89 without PS or AC and my alternator belt has a bad squeal. I have tried two different belts (new) from Quanta and they are both the same noise. Depending on the tension on the belt the squeal happens at different RPMs. Is it possible I have a wrong pulley or am I missing something that you can tell from my pictures? I am pretty sure it's not the alternator or water pump. Thanks for any insights.

Bill Hyndman

[Keith B.]

Re: 1968 L89 Belt Squeal

Did you run the engine without the belt to see if the noise is stil there

[William H.]

Re: 1968 L89 Belt Squeal

Yes, no squeal without belt.

[Terry M.]

Re: 1968 L89 Belt Squeal

Thoroughly clean the pulley grooves with soap & water. Use a strong cleaner like Simple Green. Be careful about getting undiluted Simple Green on painted surfaces as it can discolor some paints. If the pulleys have ever had anti-freeze on them they will be slippery unless they are cleaned of all traces of the coolant.

[Richard M.]

Re: 1968 L89 Belt Squeal

It appears to me that the inner crankshaft to water pump pulley belt is missing? I see you have K19 also. Lots of strain in the one drive belt.

This short, non-adjustable inner belt is important to assist the entire belt-train function. Maybe this is the reason your alternator belt is squeeling as it's working very hard to keep up with the strain.

As far as the alternator belt, the Quanta belts are approximately 1" too long in their overall circumference. This may be why your alternator brace is near it's maximum adjustment. I went through this on a L71 a while ago. More info here....

https://www.forums.ncrs.org/showthre...417#post765417

Also check out post#8 in that thread. It talks about the 2 versions of the inner WP to Crankshaft belt. If in fact you're missing that belt, I suggest you buy BOTH versions, see which one works and fits best, then return the unused belt.

Unfortunately, you'll have to remove the water pump pulley to install that belt, and your K19 belt and alternator belt too.

Rich

[William H.]

Re: 1968 L89 Belt Squeal

Rich. You have a great eye and you are right on about my missing belt. I removed it a long time ago because it was loose and I had forgotten. I'll order the two belts from Quanta. Any suggestions on the alternator belt that's a little too long? Would Quanta be able to source me one an inch shorter? Thanks very much.

Bill

[Richard M.]

Re: 1968 L89 Belt Squeal

Bill,

I'm at a loss why the Quanta alternator belt is longer than the spec. IIRC I contacted them about it months ago but never got a definitive answer. When I took my measurements of their belt then, a brand new one out of the box, I took a very accurate measurement. Maybe give them a call and get them to measure theirs closely. Maybe they have some belts longer than others due to some manufacturing issues.

Your belt? How old is it? Maybe it's worn and stretched. Maybe a new belt will help yield a better fit. The only other alternative may be a replacement belt from another supplier. The Napa belt I had on the L71 was to spec, and fit better. But I didn't like the looks of the non-original belt, and I'd think you wouldn't either.

If you get some better answers from Quanta why theirs is a inch longer, please let us know.

Rich