Help Identifying Alternator

[HuD 91gt]

Hello,

 

Just curious if anyone can identify this alternator.  It came on my F54 block, so I assume it's a ZX alt but there is not identifier plate like i've seen online.  Can anyone tell by the connections on the back?

 

I'd like to put it on when I put in the new motor as it's clean and painted "pretty", but obviously need to identify it and maybe trouble shoot it on the current motor first.

Edited May 15, 2015 by HuD 91gt

[HuD 91gt]

I tried to get a little more light on the rear but it didn't turn out well.

 

 

Edited May 15, 2015 by HuD 91gt

[Zed Head]

My brain's not working at 100% right now but it seems to be on the wrong side of the block, and the thermostat housing looks weird and the timing tab doesn't look right.  What's going on with that engine?

 

If it bolts on, and has an S and an L, and the pulley will turn it, it will work.  Gotta be numbers on there somewhere.

[HuD 91gt]

Haha.   I never realized that.  I used the webcam off my ;laptop to take the photo's  Looks like it makes a mirror image of everything.  great observation.  Honestly the only markings I see are the "Hitachi" in the centre of the rear of the alt.

 

I'm just curious if I will have to do any wiring depending if this is internally regulated or not?  Honestly, I have no idea if this thing is or not.  How do I tell?

[Zed Head]

Look at the T plug in the back.  It will probably have an S and L molded in to the case.  That would be an internally regulated alternator, probably 60 amp.  Or look for a P terminal.  The ZX alternators had a P, I think that means internal also.

 

Externals have F's and N's, instead of S's and L's.  I think the T plug's in a different spot also maybe.  Compare RockAuto pictures, 1972 versus 1981 for example.

[HuD 91gt]

No S and L, nor F and N.  But it does have a P terminal!   Looks like I have a project for tomorrow!  

 

Thanks for the quick reply.

[Captain Obvious]

You should be able to tell if it's internally regulated or not by measuring Ohms from the two small "T" connections to the case (ground) of the alternator body.

 

If it's externally regulated, one of those two connections should read a low resistance to the body. About 5 Ohms. (Page EE-14 of the 77 manual).

 

But if it's internally regulated, neither of those connections will have a low resistance to the body.

 

In other words, if it's externally regulated, you should find that one of the small connections has a low resistance to ground, but if it's internally regulated, you won't. Note that I haven't actually tried this, but looking at the schematics of the alternators it should be an easy way to tell.

 

 

[Chickenman]

Get a magnifying glass and look for some faint stamping around the circumference of the rear shell. On the surface near the Field windings. If you see some numbers that start with " LT " it's externally regulated. If you can see " LR " it's internally regulated.

 

Re-manufactured alternators are often sand blasted, and it makes the numbering hard to see. But a Magnifying glass will usually show up some traces.

 

Edit: " P " terminal pretty much confirms an Internal regulated alt. I don't think any of the external regulated models had the " P " terminal... but I'm not 100% sure on that.

Edited May 15, 2015 by Chickenman

[HuD 91gt]

Finally got around to mounting the alternator up.  The car runs fine, although it seems the ammeter (or voltmeter?) is bouncing all over the place.  It seems to sit in the middle on idle, and when revved up I see a charge of 20-25amps, it also bounces around quite a bit.  The old alternator was very stable, and didn't bounce at all, it charged from 0-10amps.

 

One thing that may be causing this is the wire connected to the "E" on the alternator is loose.  The bolt seems to be slightly stripped and I can't tighten it down.  If it is a ground, could I ground it somewhere else on the alternator?

 

Edited June 7, 2015 by HuD 91gt

[Zed Head]

E is the ground stud (Earth).  The alternator should be grounding through the alternator case also.  You can run another wire to anywhere on the case, or the mounting brackets.  Could also be that your engine is not grounded properly since the gorund through the case and brackets is usually enough.  You could run a ground wire from a bolt on the engine block to the body or battery negative.

 

Have you converted your wiring to use an internally regulated alternator?  You can't just bolt it on and plug it in.  I think that one symptom of two regulators is no regulation.  1971 came with an external regulator.

[HuD 91gt]

Yes, I did the diode trick, and bridged the two sets of wires (one with the diode) and removed the external regulator.  I wonder if this alternator isn't internally regulated at all.  I'll have to measure the resistance at T as Captain Obvious stated.  I'll try some more grounds as well.

Edited June 7, 2015 by HuD 91gt

[Zed Head]

Here are some pictures.  Notice the 1978 is internally regulated but has no P terminal.  1981 has the P terminal.  And 1975 looks a lot different than either.

 

Did you the atlanticz wiring, or the other one?

 

One check that you can do is to measure voltage on the S wire.  It should be the top "cross" of the T.  It should show battery voltage.  That's the Sensing wire, used to regulate to.  The color will be off because it's for 1978.