LD28 - 1983 Maxima Dynamo/alternator question

[royBatty]

Howdy Folks;

i am a new guy on this board - came across my first Maxima LD28 today - grabbed the dynamo - no markings on this dynamo that I can see besides a re- maned sticker on it - the dash is digital
anyone know what amp dynamo do I have

Cheers ya in advance:

[asavage]

Hello, Roy:

Please take a minute to update your Profile (click on "Profile" at the top of any page) and add your geographic location. Maybe also add your vehicle or engine info to your Signature.

AFAIK, no Maxima with LD28 engines were available in the US with the digital dashboard -- only gassers. However, your usage of the word "dynamo" indicates you are not in the US, so different rules may apply.

Your alternator will likely be of Hitachi manufacture, and should include both the Nissan part number and the Hitachi series number. If it is native to the LD28 and was originally installed in a Maxima/810/910 chassis, it will have an integrated vane-style vacuum pump affixed to the rear of the housing.

(click on any image for larger)


Look for the Hitachi series number which begins with "LR1".

LR150 = 50a (generally used on the non-LD, smaller Nissan diesels, as well as other non-Nissan diesels).

LR160 = 60a (furnished on all North American Maximas with the LD28 option)

For pictures and information about the LR150 as fitted to the Nissan 720 pickup with the SD diesel engine, see this thread.

For pictures and information about the LR160 as fitted to the Nissan Maxima with the LD diesel engine, see this thread.

[royBatty]

Howdy Asavage:

Cheers ya for the reply :

I looked at the cabin but a moment - perhaps my non keen Nissan eye mistook the dash array as digital - only saw one " clock " = appeared to be speedo - was a type of graph sort of right angle
was more concerned with ancillaries

- work mostly Rover and Toyota diesels - parts come for U K -

The dynamo has no Hitachi tag as your foto attached . only a reman tag- no stamp of serial no - etc- so was not sure if Hitachi - Denso or GM as I know they supplied some parts to Nissan in early 80's - Saginaw et such....
does have the vacuum pump at rear

I was hoping the dynamo was of higher amp - -- Digital dash would mean higher amps needed - no?

Will clean up a bit and foto and post - also go back to Maxima and inspect closely to the dash clock /verify earlier submission

50- or 60 amp - bugger- really could use at least 85-90 amps - 105 would be best -

cheers

[dieseldorf]

I would like to add a question to this thread. I am in the process of installing the LD28 in an Astro van. Currently I am finishing the electrical wiring and was unsure about the alternator connections. On the alternator housing are two letters: L and S. The diagram in the book shows that L is connected to terminal 10 on the GP Module and S is the charge lamp. Whereas in other drawings (720 pickup) L is the charge lamp and S goes to B+. Which is correct or it doesn't matter.

[goglio704]

Don't answer till he provides more info about his project. Can't tease us like that.

[asavage]

On the alternator housing are two letters: L and S.

If it's an LD28 alternator, it should be (in the US) an LR160, and have three male spade terminals.





The LR150 (as used on Nissan 720 SD engines) has the same connector profile, but only has two male spade terminals within the shell:



Which alternator are you working with?

[dieseldorf]

I am sorry, it has the 3 connector terminal (LR160?) L, R, S. The label on the alternator is missing however.

There are only two wires on the connector attached. L and S. R is not attached.

[asavage]

OK, you have a Maxima LR160 alternator and a harness connector from a 720 pickup (or a Maxima harness connector that has had the 'R' terminal lobotomized out). No problem.

Here's a LR160 (Maxima) schematic (click on image for larger):




For contrast, here's the 720 LR150 alternator schematic. Notice how the 'S' and 'B' terminals are connected more explicitly (ie not much external wiring):



Both alternators' 'L' and 'S' terminals are the same.

The 'L' terminal is for external field excitation at startup. Alternators require a small amount of "jump start" current to get them going. In the 720/LR150 version, this initial field excitation is provided by the combined current from the Charge Lamp and external resistor. If the Charge Lamp burns out, there is still enough excitation current provided by the external resistor to get the alternator going. This is the same way that GM did their wiring for years on their early alternators.

In the Maxima/LR160 version, Nissan retains the Charge Lamp in the same manner, but moves the external resistor internal to the alternator, and runs a separate switched hot wire to feed it. The Maxima/LR160 has an extra terminal ('R') for this function.

In summary, for your Astro conversion you can ignore the 'R' terminal, and use the Maxima schematic for the Maxima alternator. Or, for the belt-and-suspenders approach, you can wire up the 'R' terminal too:

• Connect the 'L' terminal to the ground side of the Astro's Charge Lamp (dash idiot light).
• Connect the 'S' terminal to the 'B' terminal.
• Connect the 'R' terminal to a hot switched by the Ign. (but not by the Accy. position of the Ign. switch).

Note for 720 owners upgrading to the LR160 alternator: disconnect the external resistor. Let me know when you locate it. I suspect it may be in the instrument cluster.

[Whew! I want an award for this one, took me almost three hours!]

[dieseldorf]

Thanks for the info, Al.
So there is no connection to the GP module (pin 10) needed?

[asavage]

Two different systems . . . but, yes: if you are using the Nissan GPC for the LD28, its terminal 10 should be connected to the LR160's 'L' terminal too.

The SD22 (not SD25) GPC does not do afterglow, and does not monitor the engine's running condition, so it does not use the 'L' teminal.

The LD28's GPC does do afterglow, and it uses the voltage state on the alternator's 'L' terminal as one input to determine when to switch off GP Main Relay.

I've updated the Maxima wiring diagram above to reflect the add'l GPC connection for the Maxima's GPC.

[dieseldorf]

Charging and GP circuits work as designed.
I hooked up everything according to the schematics above. Have 14.28V at idle, nice.