Datsun 320 COIL WIRING

1962-1965 Datsun L320 and NL320 forums - The truck that started it all in the US. All 320-specific topics and discussion can be found here.
charliej13
Posts: 11
Joined: Mon Jan 13, 2014 9:02 pm
Car: 1965 nl320
1964 l320
Location: lebanon oregon
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With positive ground system does the - or + side of the coil go to the distributor?


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Li'l Truckie
Posts: 555
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

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Let me go check to make sure.....be back...

It's NEGATIVE (-) from the Distributor terminal to the Negative pole on the coil.

I know confusing with the positive ground because you hook the black ground wires from the fuse box to the positive (+) of the coil.

Andy

Gemmer
Posts: 96
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

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Truckie,
I went out and checked my positive ground truck and the positive (marked) side of the coil is connected to the distributor. The negative (marked) side of the coil is connected to a small capacitor located next to the coil, it then runs over to the fuse block and is connected to the fuse terminal that is the most forward.

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Li'l Truckie
Posts: 555
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

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Well shoot. All of my 320 are wired this way. Let me check the wiring diagram.

Gemmer
Posts: 96
Joined: Mon Jan 27, 2014 5:38 pm
Car: 1964 Datsun PU 320
Location: Roseville,Ca

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If that's right, how come mine runs great hooked up backwards? This is going to keep me up nights.

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Li'l Truckie
Posts: 555
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

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or better yet, why do mine run correctly..........

It's raining here and I'm trying to studying Statistics, calculating equations for Effect Size (ES) with this in the back of my mind....ugh....

I looked at my 3 x 320, one from Nebraska, Washington, and Montana, and they are all wired negative. I've never looked at this hard until this morning and just left it the way I got it.

Andy

charliej13
Posts: 11
Joined: Mon Jan 13, 2014 9:02 pm
Car: 1965 nl320
1964 l320
Location: lebanon oregon
Contact:

Post

when i got this truck the battery was hooked up - ground the generator was not working i put a good generator on it and hooked it up + ground generator charged great but engine ran bad miss firing and popping.

went to auto electric shop who did generator he had me change coil to + to dist. still ran bad checked points they were burnt.

he had me put a new coil on it runs great now but strange part is it ran great with gen. not working and wired - coil to dist.and battery hooked up - ground.

drove it that way for month just charging battery at night.

would not get spark at all with condensor hooked up like gemmer has his on - side(power into coil) moved it to dist. side of coil fired right up.

I also found the wire in dist. was bare and grounding out, must not have mattered when hooked up neg. ground but when hooked up pos. ground it must have burnt points.

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Li'l Truckie
Posts: 555
Joined: Thu Jan 02, 2014 9:28 am
Car: 3 x '65 PL 320
1 x '64 PL 320
1 x '63 PL 320
1 x '62 PL 320 - parts :(
1 x '60 PLG-222
and many more Datsuns from 48hp to over 500hp
Location: Leavenworth, KS

Post

Okay 320 fans let's resolve this (-) or (+) coil pole to the distributor or at least try to shed some light on this confusing topic.

But first, regardless of what is mention here,
1- If you system works like it is, I'd recommend just leaving it alone for now.
2- If you decide to delve into this yourself, do not forget to disconnect the battery first
3- Find a local shop/mechanic that knows the charging/ignition system for a POSITIVE ground / Generator auto/truck/tractor that can help you out along the way.

Okay, per the wiring diagrams and manual the 320 is a POSITIVE ground system with a generator to produce the electric current.

What we are most concerned with is the ignition system is specifically the Coil (1), the Distributor (2), the Fuse Box (3) and the page 2/not pictured ignition switch.

Let's follow the electrical current and start at the battery. The POSITIVE terminal is grounded and the NEGATIVE terminal connects to the starter solenoid. From the solenoid the current goes to two locations - the starter and over to the Voltage Regulator (8). From the Voltage Regulator (8) the current goes to three locations - the ignition light on the dash, Generator (7) and the Fuse Box (3).

Okay, let's focus on the fuse box (3) for a second. Note that the current from the Voltage Regulator (8) only goes to the two positions number (4) across the two fuses and onto the headlights, brake switch and brake lights. This is why these accessories come on with no key - there is a constant/continuous current.

Note the one BLACK wire coming from "power in" side of the fuse box by the two fuse position (4) - this is the power/current to the ignition switch and it does not have an interrupt/fuse. This black wire goes to the ignition switch and when the key is turned power/current returns to the fuse box to the other two fuse positions number (5).

You will notice that this power/current meets at the bottom of the fuse box, again with no interrupt/fuse, and is joined by the BLACK-WHITE wire going to the coil (1). Therefore the wire from the fuse box position number (5) is a NEGATIVE current taking power to the coil. This leads to only one conclusion - the wire from the coil (1) down to the distributor (2) is POSITIVE.

My one '64 was incorrectly wired - It had the NEGATIVE power/current wire from fuse box position (5) to the POSITIVE terminal on the coil (1). As a result I had no power going across the fuse to the other accessories, namely Turn Indicators, Temp and Fuel Gauge, and Wiper motor. None of these worked. But after changing over as previously explained the '64's turn indicators work, fuel gauge jumps around, and the temp gauge now reads overheating (hey, can't win them all).

I know what your thinking - But, but, the wire from the distributor to the coil on my 320 attaches to the POSTIVE terminal and everything still works, still runs and runs smoothly, and I have indicators. Congrats! You are not alone. After burning up the internet, email, and making a couple of phone calls, I can assure you that you are not alone. My one '65 is wired exactly like this, works fine and starts up quicker than an $85K Nissan :rolleyes:

So the question is why does my 320 work if this is the wrong. Well at this time I can't say and don't know. I would suspect that there might be some additional wiring at the fuse box. So I will look at my one '65, take a few pics and post them tomorrow night and let you know what I find out.

So till then, go luck with your 320 wiring and let me know if you have any questions or need anything.

Wiring harnesses are here -
https://www.flickr.com/photos/113742723 ... 591544806/


Image

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Az_L320
Posts: 26
Joined: Wed Mar 03, 2010 9:46 am
Car: 1965 L320,
1972 1200 coupe,
1970 SPL311 Roadster

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I went through this drill years ago with my 320. I believe the "proper" way is with the positive (+) side of the coil to the distributor. A long long time ago I had it hooked up the other way and it also ran fine. But my points do seem to last longer with it hooked up correctly.

I also talked to several old timers in the model t group and they confirmed that in a positive ground system, the pos (+) side of the coil goes to the dist.

Dale - AZ

deerio
Posts: 92
Joined: Wed Oct 22, 2014 11:43 pm
Car: '63 L320
Location: Seattle, WA

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So in my attempt to convert my 320 to NEG ground, I did a bunch of reading (most MG related) and decided to finally tackle it. Unfortunately, I've hit a wall and now I'm more confused than before.


-------------------------------------------------------------------
-My truck has been wired from the day I bought it: black wire from the body to the NEG battery post and the red wire from the starter solenoid to the POS battery post.

-The coil has been wired: NEG coil post to the distributor and the POS coil post to the ignition side of the fuse block.
-------------------------------------------------------------------


With that being said, it SEEMS as if it was wired NEG ground and already been converted right? Well I decided to try out a couple things. Now be aware, I have NO electrical knowledge whatsoever.

So I read about doing a pencil test that involved using a #2 lead pencil and sticking it in the path of spark between the plug wire and spark plug. In theory, I should get a flare between the pencil and the spark plug if the coil was wired correctly. Well it was way too difficult for me to tell what I was seeing.

So I tried using an analog voltmeter. However I checked readings with the engine running instead of during cranking (would this make a difference?) With the truck wired as I bought it, the needle was swinging downward to the negative side of the range. This means the spark was not as strong as it could be right? Well when I switched the coil wiring (so now POS coil post to the distributor instead) the voltmeter jumped up and bounced to the positive side of the range. So this is good right?

Well my question is: Why is the spark better when wired with POS side of the coil to the distributor but the battery is still wired as NEG ground? Has my 320 been converted before or not?

FYI most of what I've been doing has been based off of this site: http://cny.mgcarclub.com/electrical_systems.htm

deerio
Posts: 92
Joined: Wed Oct 22, 2014 11:43 pm
Car: '63 L320
Location: Seattle, WA

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By the way, when the battery is wired as POS ground, the spark is better when the NEG side of the coil is connected to the distributor :gotme


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