So, just to add to my misery...

[datsunaholic]

I was headed to a party (more of a gathering, but I never made it in any case) Saturday night. Only 50 miles away. Had been driving the '74 all day running errands. When the sun set I noticed the dash lights were dimmer than usual; teh headlights still seemed strong and I didn't have a multimeter with me so I figured I was having issues with the light fuse (again) and pulled over near Southcenter to check it out. Well, I headed down Orillia road and shut the engine off at 40MPH, then tried to restart it with the key... lights went almost out and no start. Uh, oh. Used the clutch to refire it and found a parking lot to check to make sure the alternator wires hadn't fallen off while the engine was still running. They were all attached, I figured I wouldn't make Bellevue but I might make it to my folks house in West Seattle.

 

Nope. Made it to Burien and the lights went completely out between exits on 509, and I was able to barely keep it running long enough to exit at 128th. Dead, not enough power to maintain ignition.

 

Called my Folks who came out with a battery from my Mom's Ranger. While trying to pull the battery cables took half the skin off a knuckle and got blood all over the battery, plus the battery cable bolts were rusted solid. Had to pry the terminals off (better than breaking the bolts and not being able to get them back on at all). That got the truck back to my folk's house.

 

Test showed no output from the alternator. The truck had a 200SX IR alternator, but the external regulator was still in the truck to provide signal to the choke relay. The bad part of that setup was that the Charge light was always on when running, and it's been that way since I bought the thing 8 1/2 years ago (when I tried "bypassing" the regulator the battery drained out overnight. Should have been a warning.) Plus the regulator I had in there was a known bad regulator out of my Mom's truck, but the one that was in the truck when I got it made the engine impossible to shut off normally. The "bad" regulator just provided power to the choke relay, cut power to the alternator field when the truck was off, and the alternator did it's own regulating. 2 broken components combined to make a quasi-functional setup. My own damn fault for leaving the cobbled-together charging system in place, but it'd worked for 8 1/2 years and I tend not to fix it if it works.

 

Anyhow, the IR alternator had died, and the nearest replacement is 50 miles away in Tacoma. However I did have a couple old stock 35A alts from trucks... the one that got replaced in my Mom's '73 when the battery exploded, and one that was still attached to an old L18 I got out of a parts truck 14 years ago (and is still in my folks garage).

 

Tried the one from my Mom's truck... was a mid-90s Schucks MSA rebuild (crap) that had a bad bearing, but spun. Well, nada. No charge.

 

Tried the old one off the parts engine. Also nothing. Then remembered the regulator was bad... so yanked the one out of my Mom's truck. Power! The alternator light even goes out. It charged! Great! Just owe my Mom another regulator... grab the battery (had it on a charger the whole time) put it in... *CLICK* no start. Check battery voltage... 12.3V. Turn on the key... voltage 8.6V and dropping (and the engine won't start). Turn off key, back up to 12.3V. Leave charger on a couple more hours, it's not midnight... Nope. Nada.

 

Crap, probably killed the battery running it low like that. Well, not gonna get a battery at midnight so I drive my Mom's Ranger back home and come back the next day (Sunday).

 

Nope, the battery still didn't take a charge even overnight, and now even through it reads 12.3V at rest turning the key drops it to 4V. It's gotten WORSE. Try to roll start it down the hill, it coughs a couple times but refuses to actually run. Now the truck is 2 blocks away halfway across someone's driveway. My Mom goes and brings her Ranger down, maybe it'll jump... it does, and I get it back up to the driveway. But if I try and turn on the lights teh engine quits. No alternator output (again?) Well, maybe the battery is just too dead. Go to the store to get another battery. Put it in. Truck starts, that's good... check charging. Nothing. And the Charge light is on again. Well, it's still daylight so run through the Hayned manual alternator diag procedures. Disconnect BATT terminal on alternator and use test leads... Alternator has zero voltage at the output when the engine is not running with the key on (supposed to be battery voltage), and with the engine running voltage is 1.2V (basically reduced field voltage from the regulator). Not good. Pull alternator agaon.

 

When I turn the alternator face up half the rectifier assembly falls out the back of the alternator. It's rusted to crumbling. Didn't notice that at 10:30 at night. Must have held up enough for one gobefore disintegrating. Damn. Should have brought a small pile of alternators with me, well, too late now. Well, never tried the other alternator (the one with the sloppy bearing) with this regulator. Bolt that one in.

 

Start truck... alt light goes out, my Mom says it has 13.2V at the battery. Well, that's good... until I revved the engine a bit. She says it peaked at 15.7V and rising until I got off the gas. Oh, dear. Well, this IS the alternator that was in my Mom's truck when the battery blew up... I bet that the battery blew up due to overcharging. I try it with the headlights ON. It stays around 13.2-13.5V. Acceptable. Good enough to drive home, just leave the lights on. Which I did tonight, and it made it home.

 

So, tomorrow I have the day off so it'll be another alternator change. I think I'll try another regulator first (I think the one in my '72 510 is electrically compatible) to ensure the regulator isn't causing the voltage spike, but I have to replace the alternator again anyway because of that bad bearing. I guess for now it's back to the old 35A ones as I have quite a pile of them off of 510/521/620 engines.

 

At least the King Cab is running again... new cap, rotor, and wires seem to have fixed the starting problem. Guess I'll know next time it rains.

 

Any more of this and I might push these things straight to Pull A Part. I haven't had a trouble-free stretch since a week before Christmas. The longest I've gone is I think 3 days without a problem in the last month.

[Icehouse]

You know what they say Doug, when it rains it pours :D

 

Why don't you upgrade to a new alternator? you live so close to Pull A Part you could run back and forth getting all kinds of alternators :D I like the 90's nissan ones because the bolt on the L series but there are all kinds of options. It just seems like getting rid of the VR in theory you improve the reliability by 50% . Unless is a rebuilt Schucks alt. then you might as well throw it away :D We have all had one of those :D

[banzai510(hainz)]

Buy Nissan alternators /starters & solid state volt reg.

 

throw away the rest or recyle them

[datsunaholic]

Well, finding Solid State regs is getting a bit difficult if you don't know that's what they are. A lot of them aren't externally any different. The one that blew out was a solid state one.

 

So I swapped out the bad bearing alt this afternoon. I picked the cleanest stock alt out of the pile (while not a "Nissan Original" the build tag has Made In Japan on it vs a rebuild tag). When I bought my '72 510 it came with 2 alts behind the seat, both of which bench tested OK, this is one of those.

 

Save high voltage, so must be the regulator (which was brand freaking new when installed in my Mom's truck and never used). About 13V loaded and well over 15V unloaded. I had a new (mechanical) one in a box, so went to install it and it's a 240Z one... same plug/wiring but a different mounting. Oh well it'll work to test. Now it's 14.3V LOADED and 13.8V unloaded. Backwards, and still kind of high. Though I think my meter is off cal because it reads a "cold" battery at 12.5V.

[banzai510(hainz)]

I notice also on mostly mechanical regualtor Ill get different readings. some on the edge of cooking the battery.

 

So I went to the solid state ones.WeLLs Brand or from Carquest at the time I bought 2. back then was 22$ apc

[Lozer]

ive always been under the impression that 15.5 v is top of the "safe" charging level. the internal regulated 280z i have will slam out 15.5 when unloaded

[datsunaholic]

Since I now owe my Mom a voltage regulator I'll probably try and see if the local Carquest can get them (they have Wells components). The Carquest by me seem to know their stuff, even the "kid" behind the counter.