A New Formula In Our Stall

[TopNotch]

My father worked in some kind of electronics job or another all his life, and  my brothers and I grew up in this atmosphere and made all kinds of electrical gadgets, including Van de Graaff generators, Tesla coils, "Jacob's Ladders", etc. If you have ever seen one of the old "Frankenstein" movies, where Dr. Frankenstein is trying to bring the monster to life with all the sparks flying... Well, that's what it actually looked like in our house sometimes when we were kids.

[GTXVette]

 don't you Mean Frank N Stein, 

[Roger]

Commandment #5 - Tarry thou not amongst those who engage in intentional electric shocks, for they are surely nonbelievers and are not long for this world.

[TopNotch]

Today I put a new coil in place of the suspect one, put in (so far) two new plugs, some injector cleaner and more gas. It actually runs pretty smooth now, but something is making quite a bit of noise. The old stick to the ear trick tells me it's the AC compressor, which doesn't make a lot of sense, because it's not engaged.  But if I take off the belt and run it, the noise isn't there, so it's something that the belt is turning. I tried the stick on the alternator and water pump also, but the noise is loudest when it's on the AC compressor. I turned the compressor pulley by hand with the belt off, and it turns smoothly. So I don't know what's up.

[GTRS Fiero]

I can think of at least 2 possibilities.  First, it could be something in the belt path.  Second, you can't spin the alternator quickly by hand.  I'd turn it with a pulley, using my drill.  That'd get it moving more quickly.

I don't know about that AC compressor, but some AC compressors have a clutch behind the pulley.  That clutch loves to go bad.

What else is on that belt, other than the drive pulley?

[TopNotch]

What else is on that belt, other than the drive pulley?

Water pump, alternator, AC compressor, tensioner, and what appears to be a pulley to fake the original power steering pump. Even without the stick, the noise is definitely louder on the firewall side of the engine, where the AC compressor is. And that's the only thing on that side of the engine.

[GTRS Fiero]

You could unplug the electrical connector from the AC compressor to verify, but it may be failing there.  Last time the AC compressor went on my 4.3, it made a rather startling noise--not a ticking sound.  On a different 4.3, the clutch went out, and there was surely a ticking sound.

Was the noise there before replacing the plugs?  Were either of the plugs on that side?

[TopNotch]

AC was not on, so unplugging it would most likely not make any difference. The plugs were replaced only because I pulled out the old ones to look at them. One on each side. No difference in sound from them.

[GTRS Fiero]

Unplugging the AC shouldn't make any difference, but it's relatively easy, and eliminates one thing.

The reason I asked about the plugs was to see if possibly something may have been disturbed in that area.  Probably the engine was running poorly enough that you couldn't have heard this sound.

[TopNotch]

The sound was always there. I just didn't want to deal with it until I got the engine running well enough to move on to the next problem.

[HarryT]

A few years back on one of the club runs, The Little Black Car developed a knocking noise.  We all tried to figure it out but could not pin it down.  I could not locate the cause even with my stethascope when I   got home.  I pulled the belt and found it was a bearing in the water pump making all the noise.
Harry

[Raydar]

It would be interesting to see if the noise was the same with the A/C engaged. Maybe something in the clutch bearing, while it is freewheeling. Once the clutch is locked up, all that you should hear are the compressor bearings.
...at least if the clutch works the way I think it does.

[TopNotch]

Maybe I'll charge the AC, and see if it works. And see if that makes the noise change. I'm guessing that, after the car has set for so long, it will need charging. I can't imagine a guy from Florida (where the car was used originally) not  having a working AC.

[Fierofool]

I think it was stock when it was in Florida.  I remember him opening the trunk to get apples that he would hand out and no one really paid attention to the engine, and that was after he moved up here.

[GTRS Fiero]

Warm apples for everyone!