Okay, the battery thing must be settled. WHO on this board has/knows how to use/can take some measurements of alternator ripple at various points?

Factual real time data, NOT theory. reality.

I think this can be a great thread, or a nightmare, I also imagine VB will be watching close.

 

What kind of data were you looking for? My multi-meter will read both DC and AC voltage and frequency at the same time.
Another think to remember is that what is running and the condition of some parts are likely to effect the results.

 

I put a scope on my car many years ago when I bothered having a stereo in it....alt whine was the issue.....

I read 700 mv of ripple on the output stud, and much less at the battery, of course....but it was still there, and of course I forget the numbers.....but I was surprised at the 700 mv level being so lo....

If you want, I can get out my old Techtronics 453 scope, and look around again.....my Fluke meter is kinda old, but still werks….. lemme know watt you want measured and where.....

 

Dig it out. Lets play.

 

See if you can get screen shots of battery neg to alternator post, battery neg to starter post, and battery neg to battery pos post.

Maybe alt post to frame ground for giggles.

 

Great timing, just got finished measuring the alt out stud to engine ground.....only measure I did so far....guess WATT!!!

200 mv ripple is all I see, and I even slowed the sweep down to a ten second rate....no lite on the screen except for the 200 mv peaks seen when I speed it up..... 17SI fresh alt, all fans and a/c running...dual spals, computer injection, C4 blower, properly grounded, all my 'lecTRICKery connections are solid/soldered, cleaned and sealed funny about that alt, the really old 17SI crapped out after many years, so about a year ago, I got another under lifetime warr from AutoZone.....and wooden I know it a very short time later it crapped out AGAIN after just 10 months....and the thing went to super high voltage pegging the meter at 18 volts and the HVAC motor was raising HELL, witch is watt alerted me to it....I about ****....I let it cool down and tried it again the next day....same ****.....HELLO AZ, I need another one.....so far so good for a couple weeks now.....Kan't win......

Hey Jeff, you happen to know anything about ONAN commercial 6500 GenSets?? 6.5 kw 27 amps at 220?? we bought an old ATT service van chebby 3500 series for a work truck it was an ATT wagon....and so I trying to figger out how to get the Genset outta there, and it won't start, I want to sell it, apparently they going for like near 2 grand here.....while others are less than 1/2 that price....go figger.....

 

If I had that experience with an alternator from AutoZone, I'd just eat the cost and go to a reputable shop that only rebuilds alternators and starters. Those guys use way better rebuild kits and they (usually) do good quality work. The HD alternator I got off the 87-91 Caprice, got checked out and redone by such a shop close to me. Zero problems, three years later. Just an opinion, as despite the lifetime warranty and 'free replacement', your time isn't free!

Just an afterthought, if you have a Carquest Auto Parts or NAPA, they usually sell a better line of parts, than the Autozones, PepBoys, etc.

 

Hated to see him shut down, but the ex.mil guy with a GREAT auto electric shop not but 3 miles away retarred entirely and so no more.....honestly if I knew where to get the AMERICAN made parts in a timely fashion, I"d do it myself, like I have done many time in the distant decades of the past.....

 

Gene, NAPA has all the parts. I have bought all Delco parts from Rock Auto. I still have some NOS starter brushes laying around.

Used to be $25 for all new bearings, brushes, diode trio, blah blah,.

 

When I installed the Spals, I installed this Powermaster unit. High amperage at idle. Dual internal fans. Diodes mounted externally with air blowing thru the heat sink. DIRECT fit on brackets with SI dimensions.
Been on there 8,000 miles, and runs very cool.

AND, its a few pounds lighter.

 

 

Your on.
I just have to do a few chores here first. In the spring, I'm jambing a two post in the garage. Lots of stuff to do to get ready.

 

 

Gene, let us know when you can measure the ripple at the solenoid stud and the battery posts.

 

Oh boy...can't wait to hear or see the real data!

Redvette2

 

I have access to a good scope, but can't measure anything on the old cars until the spring.

Trying to do a measurement from the battery negative post to the alternator with a scope or meter can be troublesome just due to the effect the long test leads can have. You can lay out a negative test lead long enough to make that run with the far end connected back to the positive probe and still read a fair bit of electrical noise. Typically, it seems to 60Hz AC that gets induced. A 3-phase rectifier has a ripple voltage that is 4%, so around 0.6V of ripple would be expected at the alternator output and it's not hard to make long test leads with the ends shorted together that read similar levels of noise voltage.

 

I suggested the same ground for all 3 tests to keep some control over the readings to be accurate.

Whatever you "EE" compadres agree is accurate is perfect.

Inquiring minds just want to know. Some decisions about these cars, probably most, are subjective.

I like facts, and what ever we find is real data, no different than all the dyno sheets we see.

I "thinkl" I read some of the later units like the one I use has less ripple. (Maybe Boones Farm).

 

So many variables to try to get a really accurate measurement...probe compensation, probe lead length, probe ground lead orientation, scope band width/frequency response, scope calibration, scope internal ground circuit, etc. Likely the best you could hope for is relative measurements by keeping the measurement hardware standardized as much as possible using a fixed shortest lead possible setup.

Redvette2

 

 

And we can put your C3 on the Dyno when you get here as well and see what that bitch puts down at the pavement:-)

im at 525rwhp:-)