Alternator output cable sparkles...

[deblen]

Originally Posted by scherzoja

Thanks for all your replies and advice.

It looks like I'm in the market for a new alternator.
I didn't get the alt. tested, but the local mechanic identified the alternator, which has no markings, as a GM alternator, like one would find in a pickup truck or down at the chevy dealer. Also, the terminal on the alternator labeled BAT is lose; wen I tighten the nut to hold the pos cable on , the stud begins to spin.
Third, after examining the engine rotation (didn't actually look at rotation because engine is not running, no oil, no coolant, no fuel, but I know it rotates CW), I realized that the alternator is being rotated backwards! Not sure for how long the PO ran with that alternator rotating backwards, but I'll guess it might have been pushed to or over it's thermal limits because the cooling fins are directional!

I'm not one to take too many chances and, since the boat's pretty much torn apart for remodel anyway, I'm going to toss this POS and get one that is appropriate for my engine's rotation, appropriate or the 464AH house bank capacity, and one that actually has a manual!.

Again, thanks or all your help and time.

Good to hear!
Normally,engines turn CW looking at front. Dual engine boats have one CW & other CCW (special rev. camshaft) PO got the "odd" alternator I guess.
Though a regular GM 10si or the 100+ amp version one wire alt. will work,suggest you get the "marinized" version,as it has "spark/explosion" shielding & possibly heavier duty components for running in hot eng. compartments @ higher avg output than a motor vehicle.
Lots of new & rebuilts on ebay-rebuilts for <$100-buy 2 & have a spare aboard.
Cheers/ Len

[hellosailor]

Explosion proof [sic] screens and whatnot are more important for a gasoline engine than for a diesel. There's a lot more to be found in "automotive" alternators than in marinized explosion-resistant ones.


The Delco companies (AC Delco and Delco Remy now) make a great variety of alternators. They're not the only ones but they are very generous about publishing technical specs so you can pick one with good output at the intended operating speeds.

In the trade, apparently a "rebuilt" alternator means "we replaced what was broken" while a remanufactured alternator has been stripped down to the frame, and reassembled with each and every part including the bearings and brushes tested and confirmed to be within the spec for new parts. So to me, "rebuilt" means basically junk yard parts that had to be fixed. And oddly enough I've had a junkyard alternator last many years longer than a number of rebuilt ones.

[deblen]

Originally Posted by hellosailor

Explosion proof [sic] screens and whatnot are more important for a gasoline engine than for a diesel. There's a lot more to be found in "automotive" alternators than in marinized explosion-resistant ones.


The Delco companies (AC Delco and Delco Remy now) make a great variety of alternators. They're not the only ones but they are very generous about publishing technical specs so you can pick one with good output at the intended operating speeds.

In the trade, apparently a "rebuilt" alternator means "we replaced what was broken" while a remanufactured alternator has been stripped down to the frame, and reassembled with each and every part including the bearings and brushes tested and confirmed to be within the spec for new parts. So to me, "rebuilt" means basically junk yard parts that had to be fixed. And oddly enough I've had a junkyard alternator last many years longer than a number of rebuilt ones.

Ha Ha-guess I never knew the difference in terminology. I will have to start using "remanufactured".
Agree 100% on Delco. A dime a dozen anywhere in N.America. Inexpensive enough to carry a spare.
Cheers/ Len

[hellosailor]

I still wouldn't know but for some generous education from JCI (who remanufactured alternators under contract to a large auto parts chain) and the Delcos. Letting those pesky customers actually SPEAK with engineers...a radical concept that bumps any vendor onto my shorter list.(G)

[deblen]

Originally Posted by hellosailor

I still wouldn't know but for some generous education from JCI (who remanufactured alternators under contract to a large auto parts chain) and the Delcos. Letting those pesky customers actually SPEAK with engineers...a radical concept that bumps any vendor onto my shorter list.(G)

(1) What is your own opinion on a new Delco v/s a remanufactured one.

(2) Marine Delco v/s Auto Delco on a diesel (same model 10SI,etc)

/Len

[hellosailor]

Len-
If I forget correctly...You won't be buying a Delco alternator new. ACDelco, or DelcoRemy, but plain old "Delco"...Alas poor Yorick, I knew him well. They're gone. And brand new they are all incredibly expensive. Varying with the model, mainly top quality. (Some few had reputations for problems, like built-in spike protection that killed the alternator as it wore out.)
Remanufactured...well, that varies with how good a job they do. In theory they can be as good as new but my luck with alternators is on a par with some celebrity marriages.


The 10SI has a good rep and should be easy to find spares or replacements all over. Since diesel CAN and WILL explode in the right circumstances (a fine fuel/air mist in the wrong combination makes a fuel/air BOMB) I kinda like the idea of going marine and all--if it doesn't break the budget. Of course on a boat you're better off with an external regulator in all cases, and that means modifying (removing the internal) from an integral unit like the 10SI.
The ACDelco CS130D-100 (100A model) is also worth taking a look at, a car/light truck product. Not as common but if you look online for the output curves and the speed range, a very impressive unit.
The Leece-Neville large frame alternators also make sense if you have the room to mount one, since the larger frame means better cooling from the start.


With any of them, bear in mind that if you idle at the dock at 800rpm, but run a 3400rpm into a headwind because Ed McMann is waiting at your house with that Big Prize Check (G)...that's more than a 4:1 rpm ratio, and some alternators can supply substantial power at the low end, while running all day without damage at the high end. Others? Not nearly so much, they may put out 1/2 as much at the low end and risk overheating their bearings at the high end.


I guess that's one advantage to Balmar: They've got a fairly limited product range and they usually KNOW what each piece is better at doing. And of course, a nice paint job.(G)
Maybe you can get a 10SI with a lifetime warranty from Autozone, who may still be using JCI as a remanufacturer (I don't know) for ~$150, but their clerks won't know either. You'd have to ask them for "a 1980 Cadillac 350cu.in." or whatever that alternator actually shipped on. Preferably at a slow time of day when you can open boxes and look for the model number stamped on it, to be sure. Obviously, that's just one less expensive option--not necessarily the best way to go.

[deblen]

Originally Posted by hellosailor

Len-
If I forget correctly...You won't be buying a Delco alternator new. ACDelco, or DelcoRemy, but plain old "Delco"...Alas poor Yorick, I knew him well. They're gone. And brand new they are all incredibly expensive. Varying with the model, mainly top quality. (Some few had reputations for problems, like built-in spike protection that killed the alternator as it wore out.)
Remanufactured...well, that varies with how good a job they do. In theory they can be as good as new but my luck with alternators is on a par with some celebrity marriages.


The 10SI has a good rep and should be easy to find spares or replacements all over. Since diesel CAN and WILL explode in the right circumstances (a fine fuel/air mist in the wrong combination makes a fuel/air BOMB) I kinda like the idea of going marine and all--if it doesn't break the budget. Of course on a boat you're better off with an external regulator in all cases, and that means modifying (removing the internal) from an integral unit like the 10SI.
The ACDelco CS130D-100 (100A model) is also worth taking a look at, a car/light truck product. Not as common but if you look online for the output curves and the speed range, a very impressive unit.
The Leece-Neville large frame alternators also make sense if you have the room to mount one, since the larger frame means better cooling from the start.


With any of them, bear in mind that if you idle at the dock at 800rpm, but run a 3400rpm into a headwind because Ed McMann is waiting at your house with that Big Prize Check (G)...that's more than a 4:1 rpm ratio, and some alternators can supply substantial power at the low end, while running all day without damage at the high end. Others? Not nearly so much, they may put out 1/2 as much at the low end and risk overheating their bearings at the high end.


I guess that's one advantage to Balmar: They've got a fairly limited product range and they usually KNOW what each piece is better at doing. And of course, a nice paint job.(G)
Maybe you can get a 10SI with a lifetime warranty from Autozone, who may still be using JCI as a remanufacturer (I don't know) for ~$150, but their clerks won't know either. You'd have to ask them for "a 1980 Cadillac 350cu.in." or whatever that alternator actually shipped on. Preferably at a slow time of day when you can open boxes and look for the model number stamped on it, to be sure. Obviously, that's just one less expensive option--not necessarily the best way to go.

AS usual-any good product gets discontinued-
Seems to be lots of 10SI type & a 100amp version available on ebay.
My VP2003 has very limited space & will only accept a 10SI size frame.Currently it has a Paris Rhone? 55amp which is adequate for my use,& I can upgrade to a 100amp version-either a P-R or what awfully looks like a Delco.
100amp is the limit for single belt IMHO,& a double groove VP crank pulley from VP cost$$$$.
If I was long term cruising,I certainly would be looking to upgrade eveything-probably won't happen now-health & age .

Cheers/ Len

[Eclipsed]

Alternators make AC and the diode pack changes this to DC. The alternator doesn't know if it's turning clockwise or counter clockwise, and it doesn't matter to the function of the unit.

[donradcliffe]

As the OP noted, some alternator fans work better turning one direction than the other, so direction matters to these units.

[DeepFrz]

Alternator fan draws air in from the rear and exhausts it out front. If you spin it backwards the diodes don't get cooled the way they should and that just may be the reason for this thread.

[hellosailor]

"Alternator fan draws air in from the rear and exhausts it out front"
Nope. Some alternators have one fan, some have dual fans in both front and rear. And if they were designed for modern automotive use, the fans are designed to boost cold air, flowing in from the front, past the alternator and towards the rear of the car.
In a modern car, everything under the hood is designed for laminar air flow to cool the engine compartment and reduce air drag. Everything. Trying to make the airflow in the alternator fight that, would be like, ah, *issing in the ocean to stop the tide.
It would also be pointless to take the HOT air from the diode frame, which is normally at the back of the alternator, and the push it over the rest of the components, overheating the regulator, windings, and frame.

Although I'm sure someone somewhere somehow has installed the entire alternator backwards, and then reversed the fan to match.(G)

[Eclipsed]

My Bad; the fans on most alternators are directional. Other than that it doesn't matter which direction it turns. The alternator on my Universal gas engine faces the rear, or is it the front, as the engine
is in backwards. With no directional air flow in the engine compartment it still doesn't matter.

[colemj]

Our Valeo and Balmar alternators take air in from the rear towards the front. AFAIK, most automobile alternators are the same (they make a reverse fan for the Corvair and other rear-engine cars). The main cooling need is the diodes, so they get the air first.

Mark