Delco 10SI, how much noise? and other questions

Just curious, is it normal for a Delco 10SI to make an audible noise while running? I have tried two different units in my '55 Stude and both are somewhat noisy. One is the one that was in the car when I bought it. The other is a reman that I believe to be of dubious heritage, as when I attempted to reclock it one of the NEW case bolts snapped merely by trying to tighten it with a nutdriver. So I think it was thrown together with cheap parts. I did drop the "old" one off to a local auto electric shop to have it rebuilt properly, as I was unable to find the parts to do it myself locally and I know that they do a good job. (even though it will probably cost me more than another "reman" from Pep Boys, it's worth it to me.)

other questions...

- Both alternators are "one wire" units. I have added the wiring to use a 3-wire connection as there's about 12 feet or more of 8AWG between the alternator output terminal and the starter solenoid (where the battery +ive cable connects.) Will it damage anything to leave this connector connected to a 1-wire type regulator? Will it accomplish anything? (i.e. will remote voltage sensing even work?) Should be academic as soon as I get my good unit back anyway. The yellow exciter wire, does that need to see a full 12V or can I connect it to the far side of the ballast resistor? (i.e. does it just need to see voltage) It would make my wiring a lot neater if I could connect it to the starter solenoid bypass terminal rather than having to run it all the way back to the firewall where I have the ballast mounted. Just for reference I am using the cheap little harness from Speedway with the diode in the exciter wire, so I can use the 3-wire 10SI without an idiot light. I did cut the red wire and extend it to the solenoid; they intended to sense the voltage at the back of the alt. but I don't like that plan.

- What's the standard pulley size for a 10SI, and what size crank pulley is generally used on the engines it is installed on (SBC?) What's a typical idle RPM? Reason I ask is I can see that in my installation, using a stock Stude crank pulley, it looks like I need a smaller alt. pulley to keep charging at idle. Idle speed is in the neighborhood of 600 RPM. With lights, defrost, and heat all on (only accessories installed at the moment) I'm showing a discharge. What's the maximum RPM that I can safely turn a 10SI before the windings start flying apart? Max engine RPM right now is probably around 5200 but a cam change is planned, so that may increase to around 6000 or so.

thanks,

nate

Reply to
N8N
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It's normal for any alternator to make a whirring noise while it's under load. It's not normal for any alternator to produce clearly audible mechanical noises while spinning.

Yeah, but didn't we figure out that these aren't Delco units, but rather Chinese crap? Or they started out as Delco units but were 'remanufactured' with low-quality Chinese replacement parts?

Can't comment on your question here, as I've always viewed these "1-wire" conversions as a halfassed way of putting together a charging system.

DS

Reply to
Daniel J. Stern

With the engine running, and the only load being the ignition and whatever small current is keeping the battery topped off, it sounds louder than I imagine it should be. I would describe it as a "whirring" but it's loud enough that I can distinctly hear it in the car, even over the exhaust and open-element air cleaner (although I don't have any carpet installed, so that doesn't help)

Quite possibly. Not sure about the first one, but both were definitely rebuilt/reman as the old one had the amp rating ground off the case, and the second one was clearly a cheap reman.

I agree, and I'll rectify (heh) the situation. Actually after I posted the last message the shop called me to tell me my "new" alternator is ready, even though I just dropped it off yesterday afternoon. So next weekend we will see. I guess my only remaining question is given the above, should I be concerned if I can still hear the allternator inside the car or just drive it and be happy? Also would like some input on allowable RPM in case I still have an issue with low output at idle. My goal here is when I'm done with the car I would like it to be usable as daily transportation if required, even if I don't necessarily use it as such. Basically I want a "turn the key and go" car, even if it has a '55 Stude body.

nate

Reply to
N8N

I have the 12SI in my Jeep and at 600 rpm with everything on it does not charge. Mine needs about 700 rpm to be on. At 650 rpm it just holds even.

The excite is hooked in before the ballast but if I had a 4 banger the schematic says the excite is a 15 ohm ballast wire. Your diode will eat about .8 volts. I guess that means you can try it after the ballast....

Mine is a bit noisy too.

I believe I already gave you my pulley sizes didn't I?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

Hmmm.... I don't know enough about what the average current draw is of my coil or the alternator to handwave whether that would work or not.

You may have, but I was having news server issues a while back so I may have missed it... (teranews is now Tango Uniform, BTW...)

nate

Reply to
N8N

never mind, I just searched for it in google groups, 7" crank pulley and 2-3/4" on the alt. right?

thanks

nate

(yes, this project is taking a lot longer to finish than I anticipated. But I anticipated that )

Reply to
N8N

N8N, is it quieter when the output wire is disconnected, i.e. when it is not charging? Agreeing w/you & Dan about the 1-wire system being questionable, it may be trying to charge all the time, needed or not!? s

Reply to
sdlomi2

Haven't tried that, but I have an ammeter not a voltmeter and it does not appear to be overcharging. As it is I just need to find the time to pick up my "new" unit and hopefully problems will disappear...

nate

Reply to
N8N

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