'72 240Z Rebuild

[Zed Head]

If those two were sitting in front of me I'd measure resistance to ground through F and N on both. If they're both the same and they both worked with the external regulator that would tell something.  Alternators do short internally sometimes.  Still need the right alternator though, in the long run.

[siteunseen]

Yes it's a reman. I guess I could take both and have them tested?

I'll compare part numbers tonight from rockauto and some other stores. 

[siteunseen]

Blue has a tech tip about using the zx on his 77 with the same connections. No plug from Dave. 

I have some reading to do tonight.

[Zed Head]

Hey, I'm not sure I'm writing right.  It is clear that the 77 alternator IS NOT the alternator to use with Dave Irwin's ZXP plug, right?

Or are you still using the external regulator?  If so, that 77 alternator should function the same way, just put out more amps at full output.

When you mentioned Dave Irwin's pug, I assumed that you were using one.  Maybe not.

[siteunseen]

I was thinking this was external regulator, under my glove box.

[siteunseen]

The ground wire from the harness goes to the F on the old 240 one.

[Zed Head]

I don't think that's right.  Resistance between F and ground (E) should be 5 ohms, according to FSM.  If you have F connected to ground that might be your problem.  F is for Field and is a wire that gets power when the key is On.

 

[siteunseen]

But I didn't have a problem before putting the new alt. on. 

The old one that was grounded to F worked fine.

I'm getting confused. Let me do some more researching tonight.

Thank you Zed Head for helping. We'll figure it out one way or another. Pack of fuses is only three bucks.

 

[siteunseen]

I found a pre tear down picture and it really is connected to the F post.  Maybe @Zs-ondabrain can tell me why.  You can see it's to the left of the horizontal part of the T connection.

[Captain Obvious]

That's not ground on the F connection. That's ground on one of the bolts that hold the two halves of the alternator together. The "F" label refers to the connection in the T connector, not that bolt head. They just put the label very close to the bolt head so you're thinking it' related. It' not.

That bolt head is ground, but ground should really be connected to the "E" screw though.

[Zed Head]

We have a Cool Hand Luke situation here.

F and N are the T plug terminals.  You circled what could be used as E, for ground (the whole case is grounded).  So that would be right.  I would take the T plug off and measure resistance to ground from each female pin.  Maybe you pinched a wire or have a short in your regulator.  Then you could also measure power there with your meter, and the key On.

Edit - added an F and N picture.

Edited April 30, 2016 by Zed Head

[siteunseen]

4 hours ago, S30Driver said:

Possibly the newer one has a serious problem.  Is it a rebuilt from a parts store?

What we have here is failure to rebuild.

The new alternator is a piece of junk. Put the old one back on, turn the key and everything is fine. Hopefully they'll give me another one?

Goodnight John BoyZ!