Alternative Alternator

[BDA]

I'm done with the alternator for my TCS. I was getting strange activity on my ammeter, I put a new voltage regulator in it (I put in the US version since the Brit part is NLA - installing it only required bending the lugs 90 degrees so they aligned with the holes in the case). The ammeter seemed to be better behaved. Rather than bouncing around wildly or pegging at +30, it spent more time at the +15 mark, occasionally pegging at +30, but spending some time at 0. My battery discharged completely twice in the last week or so - the last time, after being on a trickle charger for a few days and driving with it for only 20 - 30 minutes. The battery is only a few months old.

So I've been looking for a new alternator and I think I found one that looks good (http://www.ebay.com/itm/IAPCO-14199-Rebuilt-45Amp-Alternator-for-1971-78-Colt-Arrow-Challenger-Sapporo-/231338371111?hash=item35dcd76827:g:dsIAAOSwfcVUHMsA&vxp=mtr). I thought I'd see what you guys think.  It looks like it would mount mechanically pretty easily, I assume the electrical connections would be straightforward, and it's really inexpensive!

So... Does anybody have any comments? If you think my alternator is salvageable, I'd like to hear about that too.

[Grumblebuns]

The only major issue I can think of is the width of the ears to fit over the twin cam bell housing bracket for the swivel mount, can't tell from the photo. Electrically the only issue is if the OEM pigtail will fit the new alternator. If you have to swap out the pigtail, these guys may have what you need.

http://www.repairconnector.com/categories/ALTERNATOR-CHARGING-SYSTEMS/   

[BDA]

Thanks for the link for the pig tails, Joji. I'll ask the vendor for the width of the ears. My mounting lug is a bit shorter than stock so it would fit the BDA head so if it's close, it should work.

[EuropaTC]

Now that's an incredibly cheap alternator ! 

I'm with you, at that price I'd swop it out even if it meant making an intermediate bracket to get it on the car. At least with a complete new alternator you can tick that box on the charging issues and I'd say you're going to solve the problem.

amazingly cheap......

[BDA]

Thanks Joji and Brian. After I find out if it has an international VR, I'll get it. Wish me luck!

[jbcollier]

Sounds like you have a draw on the battery that it running it down, and, possibly damaging it.  Batteries do appreciate being run right down.  If you can test the cells individually, that will give you a good idea as to its health.

Do you have an ammeter?.  With everything off and doors closed, disconnect one battery post and put the ammeter in series between the cable and the battery.  Anything over 40 milliamps is not good.

What's the voltage across the battery at idle?  At 2000 rpm?

[BDA]

Thanks, John. I don't have an ammeter (other than the one in the dash). I tested the voltage a while ago and it was in the mid 14 but erratic, generally increasing with rpm. I've put in a new VR - using the US version and bending the lugs to point out of the back of the case rather than the side.

I've been looking at a lot of alternators and I'm liking one for a Miata. I've heard a lot of good things about them. They are at least 65 amp and I'm wondering if that's too much.

[Grumblebuns]

An alternator will only output as much as the load requires. If load is greater than the alternator output, then the battery starts discharging. You should be fine with the Miata alternator.

[BDA]

That's kind of what I figured, but I wasn't sure if there might be a problem - it seems I had heard something like that in the past. Now I know why I should have taken my EE classes more seriously!

[EuropaTC]

To add to Joji's comment, the A127 alternator on mine is a 75 amp one and even if the car has taken a few turns to wake it up, it rarely passes 15 amps on the dial. Maybe a quick surge to 20amps but I've not seen it go full scale yet.

You'll be fine my friend.....

Brian

[BDA]

Thanks, Brian & Joji. I'll probably order one soon. Then all I'll have to do is figure how to wire it up!

[Grumblebuns]

BDA, I don't know who makes the Miata alternator but if it's Nippondenso, look at this website on the hook up.

http://westfield-world.com/daihatsu_alternator.html

[BDA]

Thanks, Joji! It could be. It's at least similar so maybe there will be enough information on that site to help me figure it out if it's not the same.