I need some validation before I go dump a bunch of time and money.

Here's what I have.

LS-1 installed in a Porsche 911. Custom Alternator bracket, factory a/c compressor location. Short nose Camaro harmonic balancer. 1 belt to Alternator, 1 to Compressor. No other accessories. The alternator is tightened the old school way and it's never squealed. The tensioner and idler on the compressor are both new. Squeal sounds the same with the a/c on as it does off. Squeal disappears if I take the a/c belt off.

I think the culprit is the harmonic balancer. Since the compressor sounds the same on and off, it can't be that - unless by some weird coincidence both sets of bearings failed at the same time.

The a/c was recently installed but the compressor was always on the car - albeit with an old non-tensioning tensioner.

What do y'all say? Make sense?

 

Could be the bearing in the compressor pulley. With the belt off can you spin the compressor pulley by hand?

 

Yes. It spins freely. The bearing in the compressor pulley stops spinning when the compressor clutch engages, right? So wouldn't it sound different between off and on?

 

The bearing in the compressor pulley is spinning at all times with the compressor clutch engaged or not. I have seen compressor pulley bearings go out and the belt would squeal if the compressor clutch engaged or not. If the compressor was bad the belt would only squeal with the compressor clutch engaged. For the belt squeal with the compressor clutch disengaged something is putting a load on the belt and the only thing that I can think of would be a bearing that is going out in the compressor pulley.

 

Thanks. I think I'll try replacing that first...