Hitachi LR150 50A alternator

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

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asavage
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Hitachi LR150 50A alternator

#1

Post by asavage »

Getting around to writing a post I've been meaning to do for nine months . . .

I did not take as many pictures as I should have, nor could I get really good close-ups, and I seem to have misplaced some of my notes on this one (like all the part nos. and prices).

(Click on any picture for larger)

From the 1982 720 FSM, page EL-25:
Image

1982 720 SD22
Hitachi LR150-133E 17V
Nissan part No. 23099-36W04
12V - 50A

Image

My symptom was the all-too-common one: low alternator output. Not no output, so the idiot light doesn't come on. Max output of around 10A.

Remove vacuum pump, split the case. When you unbolt the vacuum pump, black oil will run all over, so prepare accordingly.
Image Image Image Image
Image

Diode Assy.:
Image Image

When the OEM diodes break, they physically pull apart, anode from cathode:
Image


With the white silicone potting removed, you can see this better:
Image

The replacement diode assy I chose is a Transpo IHR604HD-1. This is a "heavy duty" version (35a diodes rather than 25a diodes) of the std Transpo IHR604.

Supposedly, other mfgr's part nos. for this diode assy. are:
Hitachi L150-13204
Isuzu 8-94237-729-0
Nissan 23232-W1700
New Era D-051
Standard D-32
Wai 31-8106
Wells DR307
Renard 11152
Unipoint REC-661
Echlin AC70

Image

As you can see, the diode trio lead is bare, so I had to transfer the ring terminal over. Soldering every connection is imperative, you cannot get away with crimp connections only.

I used a spacer (carpentry pencil, in this case) to support the new diode assy. to the stator whilst I soldered the delta leads to it:
Image

Voltage Regulator:
According to my local guru, the broken diodes' connections cause wild voltage spikes that weaken or destroy the integrated voltage regulator. For that reason, he always replaces the VR.

I chose a Standard VR175, mainly because I could source it in a reasonable timeframe.

Image Image

In case you missed it, there's six low-heat solder connections to the VR terminals.

Bearings and seal:
I replaced the bearings:

Rear = NTN 6202LB, I used Federal-Mogul 303-CC
Front = Koyo 6303RD, I used Federal-Mogul 202-FF

They are commonly stocked part nos., no problem buying them "anywhere", but avoid the cheapest ones for long service life. I did not buy this special brg with the outer dual seal silicone strips. Instead, I bought the generic-style brg, and mounted it with silicone/RTV. Its purpose is to direct the majority of oil that might leak past a faulty shaft seal, through a drain hole in the bottom of the housing between the seal and brg, trying to keep the mess outside of the electrics.

Image

The rotor shaft to vacuum pump seal is a mandatory replacement item, any time you disassemble this kind of alternator that has an integral oil-lubed vacuum pump on the back. It's common for the OEM seal's lip to wear a groove in the rotor, which can make sealing this area problematic. There are three approaches to overcoming this. One is to replace the rotor (expensive!), another is to drop a spacer washer in the rear housing bore that moves the seal in the housing slightly, which places the seal's lip on an unworn location on the shaft. The third approach is to use a double-lip seal (in combination with the spacer washer, if desired), which is what I do. [EDIT 03May2014: See further in thread about SKF Speedi-Sleeve repair of grooved rotors.]

Image

Those slip rings shown are in exceptionally good condition: they've been replaced, sometime before I got to it. Don't expect yours to look this good.

The seal that I removed was an NOK AE8407G, which IIRC didn't interchange to nuthin'.:
Image

I have not found a wide source for this seal. I get mine from my local guru: PHLE 15x32x7.5/8mm, 41-81700-1, about $6 [edit 03May2014: member Corky reports he was sold a 15 x 32 x 7 TC double-lip seal. They seem to be fairly common, armed with that info]:
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Brushes:
They wear out.
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But they're easy to replace, even without removing the alternator (unless you have A/C, which hides the brushes' access cover). Some soldering is required.
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I think I used Standard JX118 brushes. They are 1.125" long when new.

The end of the brushes (in the Hitachi design) are angled. It matters which way they insert into the holder. I found that if installed backward, there is not enough surface area touching the rotor's slip rings for the VR to be able to put enough current in the field to start the alternator, so pay attention to the way the brushes are installed into the brush holder.

The slip rings get grooves worn into them from the brushes. Anecdotally, this wear is worst when the brushes reach their end-of-life: the spring tension is reduced and arcing can remove material. So far (as in brake rotors and drums), I've been able to get away with merely replacing the brushes in almost all cases. The new brushes take some time to wear in (grind in) to the old slip ring grooves but will eventually work fairly well, if at reduced output. Most slip rings have little material available for lathe work. Rotor rebuilders can install new slip rings, and I've had that done too in one case. Now you know why I never throw out the old alternator: core parts are valuable.

Testing:
With most alternators, I don't bench test, because well, I didn't have a setup. However, the alternator whose parts are pictured above gave me a great deal of trouble, so I spend a little time and built a crude alternator test bench -- sorta. I spent all of about two hours for this monstrosity:

Image Image Image

The motor is off my antique Craftsman 10" table saw (the old ones have the motor swinging off one end, which makes for one-bolt + one e-clip removal.). So is the belt :) . Two pieces of angle iron and a long bolt form the motor's pivot, as does the alternator's. A bit of flatbar for the for the belt tension spring anchor, and the rest is merely clip leads and wood screws. The base is a bit of 2x12 salvage. The battery is from the scrap pile: a "good" battery isn't needed, all you need is about 6v to start the VR regulating, and to provide a big enough load to "charge into"; I never advocate buying this brand of battery, but it was laying around, so I used it.

Not shown is the "idiot light" I plumbed in later. Faster indication of when the alternator comes on-line than watching the voltmeters.

A 1HP motor is nowhere near large enough to adequately load-test a 50a alternator, but it was good enough for what I wanted to do.

Don't run the alternator with the vacuum pump installed, unless you provide lubrication for it.

I don't recall what I did about the o-ring between the vacuum pump and the rear housing; probably re-used it. If someone finds a part number or size for it, let me know and I'll amend this post.
Last edited by asavage 16 years ago, edited 3 times in total.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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philip
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Re: Hitachi LR150 50A alternator

#2

Post by philip »

asavage wrote:Getting around to writing a post I've been meaning to do for nine months . . .
Worth waiting for! 4.0
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"
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Zoltan
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Location: Honolulu, HI

#3

Post by Zoltan »

I have a "Rebuilt for Nissan" Hitachi LR150-403-R

Most probably I have a shot IC-RG. In one month I had to recharge the battery 3 times, when key is ON the charge warning light is OFF and shortly after it comes ON, and I measure 20.6V between B terminal and the ground (EL-24 in FSM)

Instead of spending $40-50 on a new IC-RG, I can buy a rebuilt BOSCH alternator AL238X for $70.

Any comments? My only trepidation is that according to boschautoparts.com and rockauto, this alternator fits both gas and diesel. According to my FSM, the connector is different for the gas.
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
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asavage
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#4

Post by asavage »

Zoltan wrote:. . . according to boschautoparts.com and rockauto, this alternator fits both gas and diesel.
The diesel alternator is completely different: the rear housing is fitted for an oil seal and has a hole for the extended rotor that drives the vacuum pump.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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Zoltan
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Joined: 18 years ago
Location: Honolulu, HI

#5

Post by Zoltan »

I called Bosch and they have an error on their web site. They DO NOT make/rebuild alternators for our truck. AL238x and AL241X is for the gasser only. Unfortunately this error has been replicated on a lot of other web sites that sell Bosch.
- Zoltan -
________________________________
'82 Datsun 720 SD22 California model
'86 Ford Escort 2.0L Diesel
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asavage
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#6

Post by asavage »

NAPA:
Raylock Premium rebuilt = RAY 138241, $154 + $28 core
Beck-Arnley rebuilt = BA 1860416 , $219 + $40

Occasionally you'll see cheap rebuilt units on eBay, well under $100.

Now you know why I spend the time to do my own. My local guy will happily rebuild mine for me -- he gets about $190 and does a very nice job; I had him do the first one I had bad. It cost me about $120 (IIRC) of parts to repair the one at the begining of this thread, and that was brushes, diode assy, brgs, seal, VR, and that's it. I didn't have to replace the rotor, thank goodness.

It is not a Delco -- it's quite a bit more finicky work to rebuild than a (vintage) Delco. But that pretty much describes a lot of things in life, eh?
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
moose60
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Joined: 17 years ago
Location: Seattle WA

#7

Post by moose60 »

I wonder if there are any other alternators that could be adapted to these SD22 engines. I realize that the number of candidates is small due to the need to have a vacuum pump, but some may interchange(with a bit of work).

What about an electric vacuum pump and a normal alternator? Are electric vac. pumps made?


Not trying to hijack. If this goes anywhere, I'll ask Philip to move it.
Byron

82 Datsun 720 KC SD22

MPG Machine
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asavage
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#8

Post by asavage »

The electric vacuum pumps that can supply enough volume to operate the brake booster run at and above $200. I was just looking into this for my father for an unrelated project, and I was able to use an Audi PDL vac. pump instead, but those don't have enough volume.

The electric vehicle conversion folks are tapped in to this stuff.

The Toyotas and Isuzus that use an alternator-driven vac pump aren't any cheaper than the Hitachi we use.

A belt-driven vac pump can be had pretty cheaply. Even brand-new ones for the Ford diesels go for about $80-110 on eBay, but you have to fab some brackets etc to make it work, and seems more work than just fixing the existing (reliable) OEM alternator. There was a gasser Buick RWD car (1981, for certain) that used a belt-drive vac. pump. Some Peugeot diesels use the same pump, different brackets. And others. They used to be fairly easily available in JYs, but all those are getting pretty old and rare now.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
bacho
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Joined: 17 years ago
Location: Greenville South Carolina

#9

Post by bacho »

guess this is the best thread to ask, where is the output power on this alternator and how would I wire it in to a custom battery. I was working on an old ford and it was as simple as one wire got power when ignition was on, one wire was grounded and the other went to the battery. Anything you can tell me like that on this one?
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
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asavage
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#10

Post by asavage »

bacho wrote:guess this is the best thread to ask, where is the output power on this alternator . . .
Click on this pic, and follow the red wire from the battery to the alternator.
Image

Also shown in this pic (click on it for details):
Image
. . . and how would I wire it in to a custom battery. I was working on an old ford and it was as simple as one wire got power when ignition was on, one wire was grounded and the other went to the battery. Anything you can tell me like that on this one?
Can't do it that way on an old GM or this Hitachi. As shown in this diagram, you have to wire a resistance from a switched hot (say, the ignition switch or similar) through a resistance, to terminal 'L'. That's the signal to the internal regulator to start providing field current, IIRC. You can probably get away with two std 168 bulbs wired in parallel, or you could experiment with resistors, or you could measure the OEM one in your truck . . .

You also need an unswitched hot to terminal 'S'. I assume that's the reference voltage for the regulator. On GM/Delco alternators that were set up that way, I just ran a jumper across from the alternator output terminal and called it a day.

Again, do not wire a switched hot to any terminal on the alternator, you will fry the regulator and/or the diode trio.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
glenlloyd
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Location: Des Moines, Iowa

#11

Post by glenlloyd »

asavage wrote:There was a gasser Buick RWD car (1981, for certain) that used a belt-drive vac. pump.
Some Cadillac models did too, they used the familiar Saginaw vacuum pumps.
asavage wrote:Some Peugeot diesels use the same pump, different brackets. And others. They used to be fairly easily available in JYs, but all those are getting pretty old and rare now.
Early Peugeot diesels used Pierburg pumps (like some VW's) which can be rebuilt inside but require checking oil level. After 1984 Peugeot started to use Saginaw vacuum pumps which are not servicable.
Image
Image

Incorporating either of these pumps into the Nissan system seems like it would be more work than it's worth

steve a
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!
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asavage
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#12

Post by asavage »

Excellent illustrations. I recognize them both. The Saginaw one is used with different bracketry and casting in both Ford and GM diesels and the aforementioned Buick.

I ran into an SD22 in a JY last year with the OEM alternator still installed to provide vacuum, and a Delco hung above the IP for actual charging. Wish I'd had a camera.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
glenlloyd
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Joined: 18 years ago
Location: Des Moines, Iowa

#13

Post by glenlloyd »

The different models currently availble can be found here marketed by Delphi. There's a pdf catalog with images of the different models and probably a list of the dimensions too.

Sorry for the OT drift.

steve a
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!
bacho
Posts: 121
Joined: 17 years ago
Location: Greenville South Carolina

#14

Post by bacho »

So I need to run a wire from the plug in the pic to the battery, and power onto terminal L that runs through some form of resistance. And lastly jump the wire going to the onto terminal S?
1992 nissan pathfinder 4x4
1985 KC 720 4x4
1982 KC 720
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asavage
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#15

Post by asavage »

bacho wrote:So I need to run a wire from the plug in the pic to the battery, and power onto terminal L that runs through some form of resistance. And lastly jump the wire going to the onto terminal S?
Output: no plug, but a 5mm stud I think.

If I'm reading the diagram right, yes: unswitched power to 'S', switched resistance to 'L'.

The 'L' terminal is directly to the field. If you don't have some juice there at startup, the alt can't jump start itself.

You know, looking at the schematic of the regulator, it's possible that I was wrong: connecting 12v to 'L' might work OK. It's not the way Nissan did it, but it looks as if the diode trio's output is there too.

But I'm not trying it on mine :wink:
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
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