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  •  » One issue sort of solved - now have another - alternator

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    4/21/2020 4:09 PM  #1

    John Ha
    I FYI 24-7

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    From: Mitchell, SD
    Registered: 4/02/2013
    Posts: 935

    One issue sort of solved - now have another - alternator

    I found the bolt that attaches the clutch dust cover to the bell housing.  The head has a weird marking JD 8.8.  The threaded part is about 6.5 mm in diameter and threads in.  It's a very odd size (not metric and not SAE) and I can only assume that the person who owned the bellhousing tapped it for this bolt.  



    New issue with my alternator.  My existing unit, a GM one-wire 10SI, is working well but the bearings are grumbling.  So I bought an equivalent replacement and installed it.  

    All I see at the battery with the engine running (and after revving it to get the alternator to kick in) is battery voltage - about 12V.  I took it to a local Autozone to have it checked and they tell me it's good.  Back in the car, same issue.  

    I have confirmed that it's getting a good 12V at the BAT terminal and that it also has an excellent ground path - it's exactly the same hookup as the one I removed.  But all I see is 12V at the battery.

    I am very confused and would welcome any sage inputs.

    TIA

    Founding Member of the Perpetually Bewildered Society
     

    4/21/2020 4:30 PM  #2

    Rufus68
    I FYI 24-7

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    From: Knoxville, TN
    Registered: 4/26/2017
    Posts: 893

    Re: One issue sort of solved - now have another - alternator

    ...looking on the Internet, the "8.8" is an ISO Metric bolt grade designation.  A metric 8.8 bolt is about equivalent to a grade 5 SAE bolt.  Since your bolt has a metric grade marking, it is most likely a metric thread.  I would check it again.

    Reference: https://www.hunker.com/13415083/what-are-the-different-grades-of-bolts

    1968 T-code Coupe with a 302.  Nice car, no show stopper for sure, but I like it.
     

    4/21/2020 5:06 PM  #3

    Nos681
    Senior 24-7 FYI Addict

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    From: Atlantic Mine, Michigan
    Registered: 7/14/2016
    Posts: 3,337

    Re: One issue sort of solved - now have another - alternator

    John

    It is a metric graded bolt.

    What does the bolt threads look like?
    Are the threads straight, tapered, self cutting threads ( looks like a tap), tapered to a point?

    10SI...

    The single wire has only one wire to battery and no other connection (I personally add a case ground to block).

    Regular 10SI has three wire connections. Small white, small red and Battery.
    Where is your red connected?
    Most people just jumper to Battery...it works but not really correct.
    Red “should” be connected to/near your fuse box.
    Red is used to compensate for voltage drop from your battery to fuse box.

    When you turn ignition switch to “on”, do you have 12v on White wire?
    Is there an inline fuse or fusible link in that White wire?
    The White wire energizes the alternator...either from ignition switch or via a light bulb.
    The light bulb could be bad and alternator doesn’t charge.
    “Newer” cars had a resistor in parallel to light bulb.

    Last edited by Nos681 (4/21/2020 5:08 PM)

     

    4/22/2020 6:44 AM  #4

    John Ha
    I FYI 24-7

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    From: Mitchell, SD
    Registered: 4/02/2013
    Posts: 935

    Re: One issue sort of solved - now have another - alternator

    Nos681 wrote:

    John
    It is a metric graded bolt.  What does the bolt threads look like?  Are the threads straight, tapered, self cutting threads ( looks like a tap), tapered to a point?

    10SI...
    The single wire has only one wire to battery and no other connection (I personally add a case ground to block).
    Regular 10SI has three wire connections. Small white, small red and Battery.  Where is your red connected?
    Most people just jumper to Battery...it works but not really correct.
    Red “should” be connected to/near your fuse box.
    Red is used to compensate for voltage drop from your battery to fuse box.

    When you turn ignition switch to “on”, do you have 12v on White wire?
    Is there an inline fuse or fusible link in that White wire?
    The White wire energizes the alternator...either from ignition switch or via a light bulb.
    The light bulb could be bad and alternator doesn’t charge.
    “Newer” cars had a resistor in parallel to light bulb.

    The bolt - just fine bolt threads - not self cutting.  I've tried putting different taps in the hole to determine the size but none fit.  The thing measures 6.5 mm across the threaded diameter.  I dunno - next time I have it out I'll tap it for a 5/16 sae bolt.

    The alternator - just have the Bat terminal on the back and the two terminals for the plug on the side.  I was only using the Bat terminal (connected to the battery side of the solenoid) for the old one and it worked fine.  Maybe this one is different somehow and I need to use the side terminals as well.  I'll have to get a plug for it and mess around with it.

    Thanks for the input!!

    Founding Member of the Perpetually Bewildered Society
       •Thread Starter
     

    4/22/2020 7:52 AM  #5

    BobE
    Senior 24-7 FYI Addict

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    From: White Plains, NY
    Registered: 4/04/2013
    Posts: 2,665

    Re: One issue sort of solved - now have another - alternator

    I have the GM 10SI w/internal regulator installed in my Mustang.  I have wired as below, I have the #2 sensing wire connected to the battery side terminal on the starter solenoid.  The #1 terminal is connected to the ignition switch in series with a diode and warning (idiot) light.

    65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
     

    4/22/2020 8:18 AM  #6

    John Ha
    I FYI 24-7

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    From: Mitchell, SD
    Registered: 4/02/2013
    Posts: 935

    Re: One issue sort of solved - now have another - alternator

    I have tumbled to the fact that the alternator I had on the car and replaced is a self-exciting alternator, and the new one I replaced it with isn't self-exciting - apples and baseball bats.

    I learned a lot so it's not a bad thing.  

    I'll just have to wire up the new one so it works like it's supposed to.  

    I guess we can stamp this one "RESOLVED"

    Thank you all for your help!!  

    Last edited by John Ha (4/22/2020 8:53 AM)

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    4/23/2020 7:35 AM  #7

    antuxd
    Active Member

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    Registered: 4/23/2020
    Posts: 1

    Re: One issue sort of solved - now have another - alternator

    Nos681 wrote:

    John

    It is a metric graded bolt.

    What does the bolt threads look like?
    Are the threads straight, tapered, self cutting threads ( looks like a tap), tapered to a point?

    10SI...

    The single wire has only one wire to battery and no other connection (I personally add a case ground to block).

    Regular 10SI has three wire connections. Small white, small red and Battery.
    Where is your red connected?
    Most people just jumper to Battery kmspico...it works but not really correct.
    Red “should” be connected to/near your fuse box.
    Red is used to compensate for voltage drop from your battery to fuse box.

    When you turn ignition switch to “on”, do you have 12v on White wire?
    Is there an inline fuse or fusible link in that White wire?
    The White wire energizes the alternator...either from ignition switch or via a light bulb.
    The light bulb could be bad and alternator doesn’t charge.
    “Newer” cars had a resistor in parallel to light bulb.

    Yes, you are right. Red is used to compensate for voltage drop from battery. I've did it numerous times. 
     

     

     

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