Right after I put my 3G on, I started getting a slipping belt whine at startup. It would decrease with each start, and go away after about 4 tries or if the engine was warm. I assumed it was the alternator belt since that was the only thing that had changed since the noise started, but I didn't think a properly functioning alternator would have a load on it like a compressor would.

Am I correct in saying that an alternator always is essentially free-spinning and doesn't get harder to turn as the load increases?

 

The ALT is harder to turn as the load on it increases (if aligned properly with good bearings). The belt sounds too loose.

 

Must not get very cold in ole Miss. ha ha

If you've ever jumpstarted a truck with a dead battery in subzero cold weather, the first thing you'll usually hear when the engine starts is the alternator and belts groaning under the heavy load, a dead or discharged battery will present a big drag on the alternator and the engine, enough to slow the idle RPM down. It can even roast the alternator stator and diodes. That's one reason why a jumpstart is strictly just to get ya goin', the battery should be put on a charger as soon as possible to bring it up to 100% or the alternator can be damaged.

 

Right after start the battery is really "hungry" and will take a big current from the alternator (very briefly). The 3g can make something like 135 amps at full power and that really loads up the drive belt. It is a lot of load for a single belt... everything needs to be just right for it to work. Good belt (eg. Gates) and adequate tension.

A good solution was posted recently... a 2 second delay voltage regulator that can be installed in the alternator. It basically has a 2 second delay before it boosts the charge rate way up and that can fix the squealing problem.

 

And here is a link that talks of the soft start regulator.
https://www.ford-trucks.com/forums/1...onversion.html
Dave ----

 

Awesome. Thanks for the info!

 

A simple solution too (well, usually simple) would be a dual-groove pulley.
Or a larger diameter by a little bit. Go too big and you lose some charging ability especially at lower rpm, but the larger diameter gives the belt more to grab. Same as the dual belts.

Dual belts are easier on some engines than others. Depends on the orientation of the other belt grooves. But there are workarounds too.
On some engines where the adjacent groove/sheave on the water pump and crank pulleys is the same size, a second belt can be run from them to the second groove in the alternator pulley. Whatever that groove was already powering, such as the power steering pump, can often handle a slight loss of tension in the crank pulley without lowering it's efficiency.
Lots of us in the EB community are running a super long power steering belt all the way over to the alternator. The alternator no longer squeals, and the power steering pump does not seem the worse for wear.
Not sure how that scenario would play out if you're running 40" tires on that pump, but for most normal sizes up to 35's, the Ford and Saginaw canned-ham pumps don't seem to have issues.

Paul

 

I initially had a smaller chrome pulley on it because it allowed for more thread on the nut. I couldn't get it to stop squealing, so I made the original, slightly larger pulley work. It improved things, but I'm not comfortable how much tension I have to put on it to minimize the squeal.

I thought about a dual groove pulley, but I can't figure out out how to make it work. Here's my 3-belt setup, going from the engine forward:

1- crank, water pump, power steering pump
2- crank, alternator
3- crank, tensioner, AC compressor

I'm not sure how I could make it work without a lot of effort.

 

I've used a wire wheel to scuff the pulley groove if it's well polished. Don't go at it like you're wanting to reshape it but knock off the glaze.

 

That worked for me as well, but usually only temporarily. The time I scuffed it and used Chemtool carb cleaner during the process was when it lasted the longest. But the dual-groove pulley got rid of it completely and I no longer had to tighten the daylights out of the thing to get good traction.

Bulldog, if your alternator is on a standard style bracket (is it up high, or down low? Thermactor/Air pump, or none?
You might just need to use the right length spacer between the alternator and cylinder head (Ford used different lengths) to get the inner groove of the alternator pulley to line up with the inner groove on your existing pulleys.
On mine, the A/C compressor belt is way too big so the groove is not a match for the alternator anyway.

 

Got a pic of your engine compartment showing the belt layout by any chance?

Paul

 

I'm not sure I have enough room to push back my alternator to get it in line with the water pump and PS pulleys.

One thing I have working in my favor is my AC compressor had dual grooves, and they both would line up with a dual alternator pulley. I figure I could run one of these two options:

2 belts on - crank, alternator, compressor

or

1 belt on - crank, alternator, compressor
1 belt on - crank, alternator



Not sure which would be better altogether, but it seems like two of the same belts would be easier. Then, I could get rid of the tensioner.

 

Yeah, I see what you mean. The 3G is all the way up against the head (or at least as close as you'd want it) and you don't even have multiple grooves in the water pump pulley.
With the non-stock compressor things might have been worse, but the fact that it's got a second available groove that might just line up is at least some silver lining. At least until you prove it can't work.

But it might be worth trying two ways. Looks to me initially as if your inner groove is not usable because any belt trying to go all the way over is going to run afoul of the a/c idler anyway.
But that idler is maybe a gem in disguise. If your dual groove alternator pulley just happens to push the second groove out in line with the A/C belt, you might be able to use just the single longer belt over the a/c, crank, idler and alternator.
The idler actually would be able to help keep traction on the accessories.

The dilemma comes if the crank pulley groove for the existing alternator belt is a different (smaller usually) diameter than the one for the a/c. You can't drive a single diameter pulley from two different diameter drive pulleys. Just leads to slipping from another source.

You do have kind of an odd assortment there, without a multiple groove water pump pulley. But it does look from here like your pulley grooves are all different diameters at the crank. That correct?
So yeah, not going to be easy. Things would have to be re-oriented all over the place and likely it's not worth it. Or it might be if your squealing is bad enough.
I know I hated mine!

Maybe you can be the first to do a retrofit serpentine setup to one of these engines. I've got two different Ford setups in my garage but have had zero time to see what it would take to make them work. Before the folks got old (and sick) and I was spending most of my days and hours being with them, I had visions of making a setup for the 351M/400 engines using a combination of custom and factory parts.

One of those things that is going to keep getting put off until that other, way more important "job" of mine isn't as needed.

Good luck!

Paul

 

Two belts on crank, compressor and alternator is a well proven setup. OE engineered in many cases. Can you push the AC compressor forward and make it work?

 

Still has the size issue. Not a personal problem of course!
The different sizes between the crank sheaves is going to cause an issue
Not having a dual-groove idler is going to be an issue if the longer belt solution is used.
Possible alignment, but that's the easiest thing to fix usually.

If used with only one belt from the A/C and the other drive from the crank pulley, then the only thing to contend with is having a crank pulley with equal diameter grooves.

Ford probably has 200 different pulley combinations over the years. Of course, that would narrow down by hub size, pulley depth and bolt pattern, but even at that there are probably 20 applications to search through on the off-chance you could find one.
Not sure NumberDummy's database is going to include pulley specifications, but if it does, that would be a huge time saver!

If you were lucky enough to find the right crank pulley then, one belt could come straight from the crank like it does now, and the second would run around the compressor, idler and alternator and back to the crank.

But without a part number, or a big-buck aftermarket conversion option, hunting the yards and suppliers of old used pulleys could take a long time.

Man, that was a really negative post! I'm going to have to go over and sit in the corner with my legs crossed, fingers crossed, and mumbling something about peace on earth.

Paul