Slipping A/C clutch

[Mike Holleman]

Alright the verdict is in. The clutch is not slipping at all. The squeal is belt after all. The A/C guy marked the clutch to show alignment and it did not move when the squealing was happening. He found the pressures right where they should be. Checked the amp draw on the clutch. Everything with the A/C was right on. The problem is that the March serp system only allows about one third contact area on the crank pulley. That is where it is slipping. This belt has maybe 5,000 miles on it. Looks like I need to change the belt with oil changes. That sucks.
Mike

[rohrt]

maybe you could put some track bight on the belt? Belt squeel is a pretty common problem and it sure is annoying.

[ProTouring442]

Is there room to engineer an idler pulley to make more of a wrap? If you can increase that wrap to at least 1/2 of the surface, it should stop slipping.

Post a pic of the setup, I'm sure someone here can suggest a way.

Shiny Side Up!
Bill

[Mike Holleman]

If the attachments work, you'll see very little room for an additional idler. The belt contacts just about 1/3rd of the crank pulley. This belt was installed just before the 06 Power Tour. Has about ten thousand miles on it. I guess changing belts every other year is not too bad. At least I know now that the squealing is not destroying a clutch. And that my A/C is setup right.

[HILROD]

I have had bad luck with the March powder coated clear pulleys. They slip and squeal. On V belt pulleys I've just sanded in the belt grooves and cured the problem. On the surpentines I've masked off the outer parts and sandblasted lightly on the belt area. On another car I stripped the whole pulley and repolished the faces, per customer prefferance.

[Mike Holleman]

That is a good suggestion. I'll try it. I too have had very bad luck with Aluminum v belt pulleys. They flat wear out in short order. The best fix I have found for them is steel pulleys.
Mike Holleman

[KUL FIR CHICK N]

Most other manufacturers hard coat or chrome their aluminum pulleys for durability. I believe March claims hard coat, but you can't hard coat in clear. Its either dark brown or black only. Plain aluminum pulleys will never hold up. As they wear, the groove geometry goes away and they're ruined. BTW, true hard coat anodize is in the HRC 50-70 range, that's tool steel hard. Your best bet may be to buy a new pulley and have it hard coated.

[ProTouring442]

Most other manufacturers hard coat or chrome their aluminum pulleys for durability. I believe March claims hard coat, but you can't hard coat in clear. Its either dark brown or black only. Plain aluminum pulleys will never hold up. As they wear, the groove geometry goes away and they're ruined. BTW, true hard coat anodize is in the HRC 50-70 range, that's tool steel hard. Your best bet may be to buy a new pulley and have it hard coated.

Where could you get something like this done?

Shiny Side Up!
Bill

[KUL FIR CHICK N]

Most anodizing shops can do it. The trick is finding one that will do your part when they're running another job so you can avoid a minimum charge. You should be able to get it done for under $50.

[MonzaRacer]

Actually March was clear anodizing the pulleys from the info that I got but they had some outside sourcing for clearcoating after polishing, A friend of mine bought several sets and we found the clear was on part of the serpitine area, and the powdercoating does slip bad.
AS for belt squeal double check your tensioner and make sure it has belt contact in the first 20 percent of let down or the spring tension.
This usually means the first 1/4 to 1/2 in of letdown.
You should, to have proper tension, only be able to just barely slip the belt over the grooves or one of the smooth pulleys or you will get slipage, been there ,seen that.
Also so far I have found the Good year ggatorback belts just palin suck on the aluminum setups.
My favorites are Gates and the Kelly Springfield belts from Autozone, the AZ belt is made as a run in type belt ratherthan a semifinish belt like others and the Gates also leave a better run in finish too.