Alternator: clutched or not?

[Joe Walsh]

Alrighty, here is where we are agreeing and disagreeing:

We all agree that the clutched alternator was deleted at some point, whether it was during production or on replacement units is irrelevant because the clutch is not important. If there is a black cover on the pulley, it has the one-way clutch.

Mac, we disagree about how the alternator is turned off with programming. The alternator can be turned off at WOT with the PCM but it has nothing to do with the clutch. The PCM turns off the alternator by way of the regulator. The only purpose of the mechanical one-way clutch is to reduce belt noise by allowing the alternator to freewheel on engine deceleration.

Mac, I disagree with your comment that "worse hazards" such as a blown engine could occur if the clutch is removed, both because of the fact it is not used at all on the Trilogy cars and because my car has not had the clutch for approximately 40 k miles. It was removed when I installed the 8-rib pulley system. After the clutch was removed, my program still turned off the alternator at WOT until I had that feature changed with the supercharger installation.

Hope this clears it up a bit.

FORDNUT IS EXACTLY RIGHT.....I don't know why this misconception of the one way clutch's function continues to persist. We've talked about this in at least a half dozen threads.
The clutch's ONLY purpose is to allow the alternator to 'freewheel' during high rpm upshifts and thus eliminate belt chirping and squealing.
It is kinda like a bicycle's rear hub which can drive the rear tire when pedaled one direction, but cannot drive the rear tire when pedaled the opposite direction.
The clutch CANNOT be 'turned on and off' at WOT. It IS NOT an electromechanical clutch (like your AC compressor has).
The alternator's charging function CAN be shut off, by the PCM, at WOT.

BTW: As has already been stated in previous posts, the Trilogy S/C kit eliminates the clutched alternator because the S/C kit mounts the alternator 'backwards'.
Using a clutched alternator backwards will get you dead battery in a hurry.

[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?

[David Morton]

BTW: As has already been stated in previous posts, the Trilogy S/C kit eliminates the clutched alternator because the S/C kit mounts the alternator 'backwards'.
Using a clutched alternator backwards will get you dead battery in a hurry.

True, but it seems a bit of misunderstanding could be taken from your statement. To be clearer...

An alternator doesn't care which way you spin it. Clockwise or counter-clockwise the diodes are still gonna flip the voltage swings to the correct polarity and charge the battery. The reason the clutched pulley has to be removed on the Trilogy setup is because if you don't, the belt won't turn the alternator at all. All Trilogy alternators are spinning in the opposite direction from the factory, and they charge just fine.

[Blackened300a]

OK to Sum it up

Clutch on Alternator = Does nothing to shut the alternator off under WOT, Just prevents belt chirp

PCM = Shuts alternator off under WOT

Gotcha!

Jeeze you guys didnt have to type out such long paragraphs, It could have been summed up in 2 sentences!

[Tallboy]

Let's not be so quick to jump on Mac about what he meant by "worse hazzards". He never said a word about the clutch mechanism damaging anything. Re-read his post. He said "when you get up off the throttle suddenly at high RPM", and on this fact he is exactly correct. Abruptly lifting at very high RPM can be quite fatal, indeed. That's why I gently roll out of the throttle at the end of my 1/4 mile runs.

Many, if not most engines, blow up on decel, not accel. I was told this by a friend who builds Nascar and Porsche race engines, FWIW.

[JMan]

Let's not be so quick to jump on Mac about what he meant by "worse hazzards". He never said a word about the clutch mechanism damaging anything. Re-read his post. He said "when you get up off the throttle suddenly at high RPM", and on this fact he is exactly correct. Abruptly lifting at very high RPM can be quite fatal, indeed. That's why I gently roll out of the throttle at the end of my 1/4 mile runs.

Many, if not most engines, blow up on decel, not accel. I was told this by a friend who builds Nascar and Porsche race engines, FWIW.

That is quite true. When accelerating or even maintaining speed, the force is linear: that is in line with the connecting rods. When decelerating, there is no longer any linear force on to the piston/rod assemblies. At that point the force becomes mostly centifugal (Outward) and no longer is in the direction of normal movement or crankshaft rotation. This is also true of valve train and transmission assemblies as well to some extent.

A bad analog would be driving down an off-ramp. If you maintain or increase the speed in the direction your front wheels are turned, the car doesn't lean as much. If you let off during the decent, the car tends to "push" outboard. That's directional force versus centrifugal force. Of course there's a limit and balance to everything [Insert disclaimer here!]. Like I stated, a bad analog yet one you have experienced first hand.

J

[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.