plainwhiteZ

Alright my 280 just started overchraging like crazy. I did a little bit of homework and serched the site for a couple of threads. I found that this is a common problem with the 72-74's but I didn't see anything for models past that.

In a thread named overcharging a voltage regulater seemed to be the culprit. My alternator hookup should be fine. It hasn't changed sience I bought the car. So that seems like it should be out of the question. Thay also mentioned wiring isues but that went along with a tach that jumps on it's own and mine is definalty not doing that. I am getting alot of squeaking though. I am not sure if it is from my belts, they definatly need to be replaced, or a bearing. I'm going to give everything in the area a good lube and see if anything happens but I cant understand how squeaking, which usually indicates slippage, could cause over charging.

thoughts?

NismoPick

#1... Check alternator belt tension.
#2... Take the car to Autozone & have them check the alternator / voltage regulator.

jmmorriso

Then go To NAPA or Car Quest to buy the alternator. The smaller auto parts stores are more expensive on some items for a reason. Quality! You could also just get the parts you need to fix the old alternator from NAPA, if you're so inclined

chinesekid

or just go to autozone and then its life time worrenty... so you'll never need to buy one agian

turboZ87.300

Even Kragen has lifetime Alts... take it off the car and have it tested 1st.

plainwhiteZ

you guys really think I might need a whole new alternator?
belt tensionlook fine to me. why? could it be too tight or somthing?

also if it ends up just being the voltage regulator, cant I just replace that? I know I would have to take the alternator apart to do it. how big of a project would that it didn't seem too difficult, but I've never done it before. Would I have to relace the brushes too? This is just speculation I cant do anything to the car untill tomorrow afetrnoon anyway. just trying to get an idea for the time and moola this thing's going to take.

snwbrderphat540

s30's had an external voltage regulator. so idk why you all say replace the alernator cause if its charging its charging. the regulator is external! id replace the overall belt and then check the tension on it. a failing bearing in an alternator makes a wild noise. you can get the alternator checked at autozone while its still in the car. or get a multimeter and actually take it to the battery terminals while its running and get an exact voltage measurement should be over 12V but under 14V usually. the stock guage isnt a measuring instrument really so not exactly dependable.

plainwhiteZ

alright I was on my way a friends house to use his garage space an tools to get to the bottem of this thing when my alternator belt snapped off and knocked my powersteering belt off as well. So we replaced the old belts and when we test drove it, it seemed like it had stopped over charging but when I took it out again this morning my gauge once again reads +18 volts anytime I touch the gas and at idling it is in the red but not quite at 18. But the noise is gone so it was just the old belt slipping.

Guess my next stop is autozone to have it tested right?

I thought our cars had internal voltage regulators?

NismoPick

I'll refer you back to post# 2 of this thread:

S30's have external v regs.

snwbrderphat540

he is driving a S30 right? cause now he said power steering belt. ARGH!

thxone

It is easy to check the deflection of the belt...get a long flat tool like a measuring stick and lay it on the longest straight run of the belt so that it is laying flat on the belt. Now take a ruler and push on the belt in the middle and measure how much it moves...1/4" should be fine on a long span on a L28. If you have a quarter inch or slightly more your belt is probably not to tight. If it doesn't move or moves like 1/32 or 1/16" then you need to loosen that belt up!!

NismoPick

Wait a sec... I was thinking 280Z as well... but he said 280 not Z or ZX... it's in the 280zx section, so I guess he's talking about his ZX.

snwbrderphat540

yeah me to specially when he made reference to the 72-74 Z's how miss leading lol. you do have an internal regulator if your speaking of an S130 aka 280ZX that X is very important

jmmorriso

Dont listen to these guys about Auto Zone and Kragen, electrical parts from these places generally suck. A lifetime warranty means nothing if you have to keep changing the alternator until you find one that works. Nearly every electric/electronic item I have ever bought from kragen has either failed prematurely, been non functional out of the box, or so poorly built it has caused other problems. If money is tight there is a '79 at Dorris auto wreckers in Hayward and Im pretty sure the alt is still on it. The guys there will pull it for you, or you can DIY. also, I think thxone is telling you to set your belts too tight. I usually have about 3/8"-1/2" deflection, or enough tension to be able to roll the belt on its side 1/4 turn and no more.

thxone

Actually Jmmorriso, it depends on the length of the belt between pulleys, the type of belt and how much force is applied to find the deflection amount. I didn't realize which belt he was talking about until I re-read the post but if you want exact figures for the Alt belt from 1970-83 is no more than .44in (1.1cm) at the middle of the longest span or accessible span with 22lbs, (10kg) or (9Nm) of force applied with the thumb. Your Welcome

plainwhiteZ

I drive a 1980 280zx. An s130. Sorry for the confusion. The thread I found on the site when I searched "Overchrging" was part of the 240 forum, I did state however that I could not find anything for later years.

Went to auto zone and for some reason I was under the impression that somone on this thread told me they could test it without me removing it from the car. Anyway of course they cannot without a garage. their machine is not on wheels.

So, now that we know my car has an internal volt reg, if it turns out that it is bad can I just disassemble the alternator and replace the voltage regulator or is that probably too big of a job?

thank you thxone and jmmoriso for the tension info

NismoPick

Interesting... all the AutoZones (and most other parts stores) here have a portable load tester. They hook it up to your battery terminals & watch the volts / amps as they apply load.

Anyway... it's a classic sign of a worn out Alternator / voltage regulator. You can get it rebuilt or buy a new one for about the same price.

plainwhiteZ

looks like it's a new alternator then. thanks.

haha. pretty simple solution for this thread don't you think?

jmmorriso

Just please dont buy a cheapo unit. If possible, have the new one tested before putting it in the car. Looks like PITA to change the regulator yourself, if you have a soldering gun, and have electronics XP its may be fun? I paid big bucks for a lifetime warranty distributor, and after installing it and troubleshooting everything except the dist I had to take the new and old units apart to cobble one good one together. The rebuilt one had a "hitachi 1983" pickup coil in it! Thats right, the original pickup coil from when it first went in at the factory.

RodMoyes

If it threw the belt, it's most likely the bearings anyway.

Not to mention that the VR is probably toast now as well...

Just get a new alternator and be done with it already.


Rod.

plainwhiteZ

I have a soldering gun, that I've never used, which is probably older than my alternator and no electronics exp. I figure going with a new alternator is the best solution here. thanks for the advice.

thxone

Food for thought...

When I lived in Ga we had a local shop there that worked on alternators. For about the same price as a new alternator they could rebuild yours in a few days. I remember my friend taking his there and it was a 60 amp alt with an internal regulator. When he got it back it was a 100 amp alt. His lights stopped dimming when the bass hit after that and they were brighter at night. Just food for thought...you can have one rebuilt to suit your needs.

thxone

All this talk about Alts screwed up my alt. I took it around the block today and came to a stop at a light and my dash lights came on...I immediately looked at my batt gauge and sure enough it's was sitting at just above 12volts and did not move when I gave it gas. Normally when I am driving the gauge is at 14 volts even with the lights on and around 13 when I am stopped with the lights on...without the lights it stays at 14 volts. I am going to check tomorrow for loose connections (fingers crossed). This Alt was bought "new" from AutoZone...dammit.

NismoPick

GM 1 wire upgrade FTW.

thxone

Those are a dime a dozen but I would not know how to convert it.