Alternator clutch

[smokepole]

I picked up an extra 78 amp alternator at the local pick-a-part and have been searching / checking prices to rebuild and upgrade to 100 amps. While looking at replacing the pulley, I noticed most new vehicles use a slip or one way clutch to drive the alternator with the serpentine belt. My truck has a Muncie PTO pump drive on it and squeals for a minute after starting.
Does anybody use a newer alternator with a pulley clutch or would it be possible to retrofit one to my 12SI ?

[DieselSJ]

I have never seen a clutch on an alternator. Pics?

[TrailerTrash]

I have no idea what you are talking about. never seen that

unless you are attempting to talk about the difference between a ribbed pulley for a flat belt and a grooved pulley for a Vbelt

[70K10Hunter]

Been a mechanic for over 30yrs never seen or heard of one.... show us a pic of what your talking about.

[smokepole]

http://www.daycoproducts.com/stuff/c...ransparent.gif

Relatively new tech but it seems to make sense

[smokepole]

http://www.daycoproducts.com/stuff/c...388_oap091.gif

This one looks to be the most likely to fit a delco 12SI.

[nonstop]

Just looked it up. Sounds interesting, but it sounds more like a dampening mechanism . Would it be any benefit on your truck?

[v30crewcab]

they were designed for diesel engines so the belt doesn't make noise when you shut it down. not sure why you'd want one on a gas engine.

[toomany2yz]

I think I read somewhere that the new Corvettes have clutch driven accessories. Something to do with the high Rpm or how fast they rev, could be wrong though.

That being said. An alternator won't cause any drag until it starts producing a charge.

To the OP, your problem might be bad belt alignment or a worn belt that is making noise when you engage it. Or even not enough tension on it.

[andyh1956]

Oh yeah ALL the military vehicles we have now have an OVER RUNNING Clutch pulley on them. All the MRAPs, the LM & FMTVs, HMMWVs. They gave there fair share of trouble in Afghanistan, the rollers would stick & not drive the alternator.
The thinking was that this being a 500 amp alternator that sudden de-celleration would cause the heavy armature to over travel the belt & break it. On a pickup it's just another toy. Remember when it come to a truck SIMPLE is BETTER!

[homemade87]

Originally Posted by toomany2yz

I think I read somewhere that the new Corvettes have clutch driven accessories. Something to do with the high Rpm or how fast they rev, could be wrong though.

That being said. An alternator won't cause any drag until it starts producing a charge.

To the OP, your problem might be bad belt alignment or a worn belt that is making noise when you engage it. Or even not enough tension on it.

This is correct . They used them in performance engines to compensate for the quick decell of the engine from quick rpm changes . I think what they were trying to do was take some of the drag off the belt to keep the belt from over coming the belt tensioner and loosening at quick rpm changes . It does not slip under load , just under quick rpm changes .

Smoke , This will not help your problem . Most likely you are dragging more than what your belt can handle when it is cold . May look into a better belt system or a better belt and tighten it up and see what happens . Also after it is warm and no longer hear the squeal does not mean it is not slipping some . It may still have some slip after warm .

May look into a bigger pulley on the pump if possible . This will slow it down some and give more gripping surface for the belt .

Just food for thought .

[smokepole]

Thanks for the input. I will rebuild the 78 amp and have been looking at the larger under drive pulleys for it. The truck has a cluth driven PTO pump for the boom that runs off the serpentine also. Guess I need to get the straight edge out and check the pulleys.

[TrailerTrash]

sounds neato. id like to see a pic of that setup

[truckin 79]

Originally Posted by smokepole

I picked up an extra 78 amp alternator at the local pick-a-part and have been searching / checking prices to rebuild and upgrade to 100 amps. While looking at replacing the pulley, I noticed most new vehicles use a slip or one way clutch to drive the alternator with the serpentine belt. My truck has a Muncie PTO pump drive on it and squeals for a minute after starting.
Does anybody use a newer alternator with a pulley clutch or would it be possible to retrofit one to my 12SI ?

I was thinking of a 10si to a 12si conversion myself for a 79 Trans Am. When I have the ac on, I have to run fan on high because blower motors in 79 have a lower output so that sucks a lot of juice at idle. I have been reading up and it looks like a cs130 is the better way to go. You just have to switch out pulleys and change wiring harness. The key is having a alternator that puts out more amps at low rpm range and it seems like the cs130 fits that bill
https://www.hemmings.com/magazine/hm...s/3728021.html