I'm looking for a photo of the alternator mounting on a '73 or '74 LS-4 with A/C and P/S. I have the AIM manual, so that isn't helpful. I spent a year locating good used mountings and pulleys, including the idler pulley. Yet the alternator pulley when mounted is one belt track further back then it should be. All other belts are in their correct tracks. If the alternator had come with a two groove pulley, there would not be a problem. According to the AIM, all mounts are installed properly. I can't tell if I have an incorrect alternator, brackets that aren't aligned properly, or the wrong pulley installed on the alternator. A photo of a proper setup would be helpful. Anyone?

Steve

 

Its my '71 LS5, but I think the LS4 is similar :



And another one found in here in the forum :



I hope that would help.

 

Thank for these photos. As in this picture, I have all of the mounts and they are in the proper location. Actually, the big block setup utilizes 4 alternator mounts. This picture appears to be missing one of the lower strap mounts that bolts to the cylinder head where the two other mounts are attached (listed as a lower mounting brace in Dr Rebuild's catalog). You are missing the alternator in this shot, which would be helpful to understand how the belts align. Just as your photo shows, the alternator belt (and the A/C and AIR pump belt as well) run on the outermost 3rd track. My alternator has a single groove pulley which lines up with the 2nd belt track. The 3rd track would align with the outer pulley of a 2 groove pulley. Does your alternator have a double groove pulley like the next photo?


This shot offers a glimmer of light. While this doesn't have the original alternator (anyone know what model alternator this is?), it does have a double groove pulley, and the belt is running in the outermost groove. This would most certainly solve my belt alignment problem, but the AIM manual and the service manual do not show the alternator with a double groove pulley. And I just don't recall these engines utilizing a double groove pulley.

Interestingly, I just looked in Zip Corvette's newest catalog and they list a separate pulley for the '72-'74 454 with power steering vs. non-power steering. Dr Rebuild also lists a separate pulley. It looks like I'm going to need to find a double groove pulley (or order one). Can anyone else confirm the use of a double groove pulley?

Steve

 

No - there's not a double-groove pulley on a '74 LS4 with power steering. The alternator runs off of the power steering pulley as shown in the photo above.

 

The alternator in the second (cleaner engine) shot is a modified CS144 alternator. Its dark now, so tomorrow I'll take a shot of mine and post the pic. here.

 

 

Well, I have to admit to some serious confusion. I stopped by a local alternator shop earlier this week and they located a double groove GM alternator pulley; not date correct, but correct for the old style alternator. Came home last night and pulled the alternator, removed the single groove pulley, installed the double groove pulley, and reinstalled the alternator and the belts. My problem is solved. All of the pulleys line up, and all of the belts track straight. Guy, does your '74 have A/C?

So tell me what is wrong with my installation. Here are some photos, and yes, they are lousy. It's tough to get a good shot with the hood in place. Ignore the aluminum bandaid holding the fan shroud together. And realize the AIR pump and the A/C compressor are still sitting on the bench. As you can see in the first photo, the alternator belt runs in what the AIM calls the "third track", and lines up perfectly with the outer groove on the power steering pump pulley and the outer groove on the new alternator pulley. If the A/C compressor and AIR pump were in place, that belt would run from the empty outer pulley on the water pump.



Two closer shots:





All belts are tracking straight, and are in the proper pulleys. All mounts have been replaced, and everything fits properly. The idler pulley is in place and provides additional tension on the "first track" cranshaft to water pump pulley belt. So what's up here? Why would I need a two groove pulley if a one groove is specified? Oh, and the AIM lists two different pulleys; one for A/C with P/S and one for A/C without P/S, but of course there isn't any way to tell whether the difference is the number of grooves. What would be the difference if not the number of pulleys? The diameter of my single groove and two groove pulleys are the same.

Sign me:

Steve the Baffled

 

This is my set up and I have, since this picture was taken, added a second belt from the crank to WP with no idler.

 

Yes.

In one of the pictures, the alternator mounting bracket looked a bit strange. I'll try to remember to take a look at my configuration to see if I can help clear up the confusion. Obviously your belts line up the way they are supposed to.

 

Steve,

After viewing my configuration, it appears that your double-pulley may possibly be a service-replacement part designed for many configurations across multiple years and models. The alternator pulley on my '74 LS4 with power steering, AC, and AIR appears to be the same size as yours front-to-back, however where you have the inner pulley, I have a solid area - maybe an un-machined area intended to provide the necessary spacing in this particular configuration since the second/inner grove is not required.

So your alternator pulley fits just fine, and your belts (at least on that side) appear to be in the proper configuration. You just have a "spare" groove in the alternator pulley.

I'd post a pic now, but my camera is MIA. Maybe someone else has a pic of their alternator pulley?

 

I think you are correct, and that may explain why I don't recall seeing twin groove pulleys on these cars back in the day. It looks like the photo by ENG40 is just as you described, in which case, I'm home free. In any event, everything is aligned properly, and that was where my concern was focused. Thanks everyone for responding; it's a good feeling when parts are working properly.

Steve