Alternator: clutched or not?

[TripleTransAm]

My 1st MM was assembled in mid Feb 2003. I dug out this photo of the front of the motor when I'd had it about a month, tops.



Is this the clutched alternator that early 2003 cars got? I understand the PCM calibrations from factory (all four?) never took advantage of this function?

My 2nd MM's alternator looks 100% the same. BUT... when I got my alternator replaced last month on the 1st MM, the alternator that was put on there appears to look the same except for that black 'disk' up front (the one with the white dab of paint pointing down to the crankshaft hub). There is no such disk on the replacement alternator... I can see the big nut holding on the pulley.

Question: did they replace my clutched alternator with a non-clutched unit or is that black disk simply a plastic cover?

[grampaws]

Plastic cover!! You can pop it off and see the bearin assembly
behind it..

[bugsys03]

My 03A had the clutch alternator. When I had it replaced under warranty about June 04 they put on a standard alternator. If you have the clutch alternator, watch your amp gauge under WOT, it will go down.

[SergntMac]

Question: did they replace my clutched alternator with a non-clutched unit or is that black disk simply a plastic cover?

Answer: Yes, somewhere in time, the clutched altenator was removed from the production line. I can't say if it was part of the 300B decontenting, or, at the start of '04 production, but it left us. Replacement altenators do not have the clutch units. And, yes, it's a plastic cap covering the bearing nut.

Anyone with a clutched altenator and SCT tuning, can have the clutch function turned off, and the altenator will produce power under WOT. Anyone with a Trilogy kit, got a non-clutched replacement pulley with the kit.

Some will say that removing the clutch function (either method) will result in belt noise (or worse hazzards) when you get up off the throttle suddenly at high RPM. I agree with the "or worse hazzards", this is an easy way to blow an engine.

[FordNut]

Well, my understanding of the whole thing is a little different so here goes:
The '03 300A and possibly the 300B had the one-way clutch on the alternator. The black cover on the pulley in the picture is commonly in place on the ones with a clutch. The function of the alternator shutoff at WOT is totally thru the PCM and the clutch has absolutely nothing to do with it. The function of the one way clutch is to reduce belt bouncing, slipping, squealing in sudden engine deceleration by allowing the alternator to freewheel. The reason for the Trilogy kit replacing the pulley with a non-clutched one is that the alternator rotates in the reverse direction with the Trilogy kit so the one way clutch would essentially always slip. Bottom line, the clutch is not important.

[Paul T. Casey]

Does this mean that perhaps someone out there would like to have my never been used alternator u/d pulley?

[carfixer]

FordNut's description is exactly correct.

All Marauders that came from the factory had the clutched alternator pulley. No replacement alternators came with the clutched pulley. So, if you see the black cap, it is clutched. If you see a big nut, it is a replacement alternator.

[SergntMac]

Wait one damn second...

I posted this...

Answer: Yes, somewhere in time, the clutched altenator was removed from the production line. I can't say if it was part of the 300B decontenting, or, at the start of '04 production, but it left us. Replacement altenators do not have the clutch. And, yes, it's a plastic cap covering the bearing nut.

Anyone with a clutched altenator and SCT tuning, can have the clutch function turned off, and the altenator will produce power under WOT.

Anyone with a Trilogy kit, got a non-clutched replacement pulley with the kit.

Some will say that removing the clutch function (either method) will result in belt noise (or worse hazzards) when you get up off the throttle suddenly at high RPM. I agree with this "or worse hazzards", this is an easy way to blow an engine.

Then Brian posts this...

Well, my understanding of the whole thing is a little different so here goes:
The '03 300A and possibly the 300B had the one-way clutch on the alternator. The black cover on the pulley in the picture is commonly in place on the ones with a clutch. The function of the alternator shutoff at WOT is totally thru the PCM and the clutch has absolutely nothing to do with it. The function of the one way clutch is to reduce belt bouncing, slipping, squealing in sudden engine deceleration by allowing the alternator to freewheel. The reason for the Trilogy kit replacing the pulley with a non-clutched one is that the alternator rotates in the reverse direction with the Trilogy kit so the one way clutch would essentially always slip. Bottom line, the clutch is not important.

So, which one of us is right? Or, wrong? Are we not both explaining the same thing? So...Why this post?

FordNut's description is exactly correct. All Marauders that came from the factory had the clutched alternator pulley. No replacement alternators came with the clutched pulley. So, if you see the black cap, it is clutched. If you see a big nut, it is a replacement alternator.

Y'all tell me...If I did not post a correct answer to the question as posed, show me why?

[SergntMac]

Anyone with a clutched altenator and SCT tuning, can have the clutch function turned off, and the altenator will produce power under WOT. Anyone with a Trilogy kit, got a non-clutched replacement pulley with the kit.

Most of this confusion is my fault, this paragraph is very poorly worded, and it's thrown folks off in their replys. Everything I said is true, but I said it all wrong. My apologies to all.

There is no relationship between the clutch action of the altenator pulley and EEC programming. My bad. Moreover, there once was a clutch, now there isn't, and I know very little more about all that. Not knowing more, I should not have made the comment. My bad again. BTW, I still have my OEM clutched altenator.

It's also true you can turn your altenator on full time via EEC software, and I strongly recommend this to anyone who races, or, drives hard on a routine basis. With the altenator shut off under WOT, the whole car and all of it's devices and accessories are driven by the battery. A "brown out" is possible, and the device furthest away from the battery will suffer first. That device is the electric fuel pump, and when voltage drops, pump speed drops and fuel flow to the front of the car is affected. The end result is a lean condition at high RPM, and just when you're begging for more power to win the race, you run out of fuel. This is the rationale for adding a Kenne Bell Boost-a-Pump, which boosts the voltage to the fuel pump under WOT. However, with out a BAP in place, one is asking for trouble. BTW, don't race with less than 1/4 tank of fuel, baffles inside the fuel tank can cause the pumps to run dry during WOT.

Now, there is a device in the trunk called a "fuel pressure delivery module" that monitors the fuel system. When it senses a disruption in expected behavior, it reacts, and that reaction is to shut down the fuel system. This, of course, is potentially harmful to the engine. Sudden loss of fuel and spark at high RPM will twist a con rod and window the block, usually #4 or #8, but all are at risk. This is the same as jumping off the throttle at high RPM. Bad, very hard on stock con rods, forged rods are not immune, but that's another thread.

So, you see how I fu*ked this up, don't you? Right train, wrong set of track, or, something like that? Ya know, I never should have brought it up in the first place.

Oh...One other thing. I've got a Helms book, actually two, dated 7/2002, just a few weeks after my MM came off the production line. This is what the techs at my dealership use, that why I bought it. Anyway, I peeked at it briefly this morning before leaving for work, wanting to see how close FordNut was to the actual text of the book, i.e. exactly.

If I am to trust in, and believe everything I read in this tech manual, we all have a problem, folks. According to Helm, as of 7/2002, Marauders do not have an altenator. That's right, no altenator, nope.

We have generators, and regulators, and the sketches look just like what's under my hood, but no altenators. The word's not even listed in the index. So much for exactly out of the book, eh?

In the words of John Bon Jovi...have a nice day...

[metroplex]

Can the clutch be retrofitted to Crown Vics?

I have a 4G alternator that is used on the Mark VIII / Cobra (6G is used on CVPIs and Stangs) which looks just like the MM alternator.

[DEFYANT]

My company car, an 04 CVPI, also has a clutched altenator. FYI.

Mac, can you elaborate on this comment?

Some will say that removing the clutch function (either method) will result in belt noise (or worse hazzards) when you get up off the throttle suddenly at high RPM. I agree with the "or worse hazzards", this is an easy way to blow an engine.

Thanks

[Donny Carlson]

Knowing that my Marauder had a clutched alternator, I was surprised to find that the alternator in my new SSR didn't have one. Unpleasantly surprised, because there was a loud belt chirp/squeel on the 1-2 shift under WOT, a shorter chirp at the 2-3. Chevrolet had issued a TSB, the fix was to replace the alternator with a clutched alternator. My truck is an early '05 model year build, there were a set of running changes made the month after mine left the plant. Apparently the belt chirp wasn't an issue with the 5.3, but more powerful 6.0 LS2 it was.

The visial difference between the two is a black cover on the pully of the clutched alternator, just like the Marauder.

Interestingly, according to Chevy engineers, the belt squeel (which happens only at WOT) is not a durability issue, though they certainly don't hesitate to pay the dealer to change it out for free under warranty.

[TripleTransAm]

By the way, the factory wiring diagrams support the fact that the alternator clutch is not electro-mechanically controlled by the PCM, in fact it is the alternator's charging function that is controlled by the PCM. No other wiring to the alternator as indicated in the diagrams.

So I'm okay with sticking with the mechanically clutched unit, then?