Alternator Swap oddities (minor)

[mimregi]

Had a great break with the car -- installed headlight relays, tightened up my shifter, put on a new water pump (those issues documented elsewhere) and dropped in a new alternator.

I started the process with the alternator and realized I had the wrong one (one I ordered from e-bay -- I hadn't done my homework properly and ended up getting what was basically the same alternator). I went to advance and ordered a reman from an '83 280zx. It bolted in (mostly) without issue (the mounting holes were slightly too small, but I suspect my car and not the alternator was to blame there, easily remedied in any case), and wiring was pretty straightforward. I pulled the VR, snipped the plug and made the terminal for where the VR had plugged into the harness.

We were doing the relays at the same time, so after (finally) doing that, getting the water pump re-attached and whatnot, it had been hours before I started the car. It roared to life and all seemed well... until I found that I forgot to plug in the little terminal after the liquid electrical tape (my new favorite thing) dried. After having done the research I had done, I expected the car to not shut off, but it did.

That all said, I have 3 questions:

1) Do I need the terminal? It is plugged in now, but I am kind of at a loss for what it is or should be doing.

2) Any guidelines for belt tension adjusting? I read somewhere about .5 inch of slack, but "slack' isn't an exact science, and that felt pretty tight to me, so I loosened it up a bit more. Any tips there?

3) I'm not an electrician -- is there anything I should be watching out for to make sure that the install went well (besides the obvious battery not recharging stuff)?

[Zs-ondabrain]

What type of relay set up did you use for the headlights?

[Arne]

It is my understanding that some of the later '73 240Zs do not require a diode. Sounds like your car is one of them. In that case, the diode will do no harm, it is redundant.

But you do need the rest of the functions that the jumper wires provide to complete the charging circuit. So plug it in.

[=Enigma=]

Keep in mind that this is not Z specific, but rather something I remember from auto shop or something I read, and that is that the the deflection at the longest span between pullies should be approximately 1/2" when 20lbs of force is applied. It's a game of estimates really.

[mimregi]

Thanks all!

Dave: We followed your plans for the harness (we being me and a friend of mine with a lot more knowledge about electrical stuff than me -- he did pretty much all the wiring while i did the alternator and water pump). We only did the headlight one so far, but got it working. We ended up doing it ourselves because someone has messed with the wiring in my car and, as expected, we had to go "off script" a few times. I'm afraid I cannot intelligently describe exactly what from your diagram/instructions we had to change, but if you are real curious, I can try to get him to jot down a quick explanation.

Arne: Thanks =) Sounds like the first time I started up the car there was no recharging going on then (it wasnt on very long). I will definitely be leaving well enough alone.

Adam: That sounds familiar... I'm pretty sure my belt is a bit loose right now, I'll have to get in there this weekend and tighten it up (pretty sure I am going to need to pull the water pump again anyway =/ ). Thanks.

Today will be my first real driving day with her again, so fingers crossed, battery will stay charged, lights will all work as expected, temp will stay down and all will be happy.

-m

[bears240]

Had a great break with the car -- installed headlight relays, tightened up my shifter, put on a new water pump (those issues documented elsewhere) and dropped in a new alternator.

I started the process with the alternator and realized I had the wrong one (one I ordered from e-bay -- I hadn't done my homework properly and ended up getting what was basically the same alternator). I went to advance and ordered a reman from an '83 280zx. It bolted in (mostly) without issue (the mounting holes were slightly too small, but I suspect my car and not the alternator was to blame there, easily remedied in any case), and wiring was pretty straightforward. I pulled the VR, snipped the plug and made the terminal for where the VR had plugged into the harness.

We were doing the relays at the same time, so after (finally) doing that, getting the water pump re-attached and whatnot, it had been hours before I started the car. It roared to life and all seemed well... until I found that I forgot to plug in the little terminal after the liquid electrical tape (my new favorite thing) dried. After having done the research I had done, I expected the car to not shut off, but it did.

That all said, I have 3 questions:

1) Do I need the terminal? It is plugged in now, but I am kind of at a loss for what it is or should be doing.

2) Any guidelines for belt tension adjusting? I read somewhere about .5 inch of slack, but "slack' isn't an exact science, and that felt pretty tight to me, so I loosened it up a bit more. Any tips there?

3) I'm not an electrician -- is there anything I should be watching out for to make sure that the install went well (besides the obvious battery not recharging stuff)?

I have done the same alt. conversion you speak of the reason you have jumped the wires at the regulator location is one wire senses the batt voltage at all times and regulates accordingly, while the othe provides 12v while you start the car so it produces a generating field from the get go, and you dont have to rev the car to like 2000 rpm to start making charging voltage. a good test for your alt. is a basic volt test at your batt. with a multimeter. Start by testing with the car off, you should be at around 11.5-12.5 volts. now start the car and repeat test, now voltage at the batt. should be around 13-14.4 or really close. this is a good charging voltage the only time you really can't pin point an alt problem with the correct voltage is if the diodes go bad, you still will sometimes get the proper voltage, however the bridge could be bad and you diode ripple vill be wrong. your local auto parts store should be able to rund a quick free charging system test for you. hope this answers at least one of your questions.

[mimregi]

Funny epilogue here:

The car wasn't getting a charge at all. I almost jumped right to the boards, but decided to show a little self-reliance first and troubleshoot the damn thing myself =)

It didn't take long looking at things to realize that one of the wires I jumped was connected to nothing (I had followed the directions at zcarcreations and worked exclusively with the plug I snipped, never really looked at the harness -- one of the wires I jumped was connected to the 6th, empty female on the harness). A bit more research (the post by Dave240z in this thread did the trick for me), a bit more jumpering and all appears to be a-ok now (my dash meter is showing at roughly +20 now -- I assume that is good, seems logical). I left the diode in just because and the belt still seems just a hair a bit on the loose side, but I need an extra pair of hands to get it any tighter.

Thanks as always to all on these boards =) I always try to put a closing chapter on my stories.