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metalmonkey47

NO SPARK on '76 620

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Your wireing what I see looks correct.

Get a 1.6 ohm or close it ballast reisitor as that what the specs are.

However:

You could substitute the .8 ohm ballast in there just to trouble shoot and see if it runs for a few minutes.Then you know its the proplem.

But in in Therory the truck should start Running IN START as your not using the ballast resisitor while your holding the key in START

 

But like earlier you said you didnt see carb squirting also.

 

but I would fint the stock post type as you have so you dont need to put on different connectors or however you going to do it.

 

Your Avatar say Datsun mechanic?

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I'm gonna have to answer all questions in the morning. Just got home from work, and haven't had time to play with it. Nearly midnight here.

 

It kinda looks like there is a damaged wire coming out of the plug Black/Blue at the ballast resistor. Is it damaged? What is it connected to?

It was okay. I already wired in the new resistor and had to replace the ring terminals. Wasn't worried though, just soldered on new terminals and slathered it in di-electric grease and some heat shrink tubing to keep it fresh. Truck still doesn't run.e

 

Your wireing what I see looks correct.

Get a 1.6 ohm or close it ballast reisitor as that what the specs are.

However:

You could substitute the .8 ohm ballast in there just to trouble shoot and see if it runs for a few minutes.Then you know its the proplem.

But in in Therory the truck should start Running IN START as your not using the ballast resisitor while your holding the key in START

 

So in this case, the resistor is obviously not the problem. Regardless, it's got a new one on now since the old one was broken. I'll make sure to get one with the proper spec as soon as I get a chance to source one.

 

 

But like earlier you said you didnt see carb squirting also.

Got a carb kit and replaced the accelerator pump. Now that problem is solved.

 

Your Avatar say Datsun mechanic?

 

 

To an extent. I'm VERY ignorant when it comes to ignition systems. Actually, wiring in general to me. Mechanical things are my sort of 'expertise', if you want to call it that. I'm much better with handling problems I can physically see. I like to learn, so I like to ask questions.

 

The positive side to these problems, is that I learn a great deal of information that I can put forward when someone else needs help. Even if what I'm learning isn't relevant to my problems or doesn't solve it, it's still +1 knowledge on my end.

 

That's part of the reason I enjoy posting on Ratsun so much. The environment here is like no other. The support from other members in completely opposite places is without equal.

 

 

 

 

With that said, I do appreciate all the help you guys have given me, especially you(hainz) and Mike. I'm still learning OHC and L-series as well as points ignitions. It's great having some information to look back on.

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The positive side to these problems, is that I learn a great deal of information that I can put forward when someone else needs help. Even if what I'm learning isn't relevant to my problems or doesn't solve it, it's still +1 knowledge on my end.

 

That's part of the reason I enjoy posting on Ratsun so much. The environment here is like no other. The support from other members in completely opposite places is without equal.

 

 

Well put MM. Nothing goes to wast here even dead ends. Years from now someone may come across this and say. "So thats how it works. I can fix mine." It's +1 for everyone. There's nothing like a gritty problem to bring out the Sherlock in us.

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It runs! And I'm sooooo fawking happy about it. hyper.gif

 

 

 

Turns out the insulator on the points where the condenser connects was cracked, and it was shorting out on the points. Fixed and now it runs great!

 

 

 

Again, thanks for all your help guys! I think I'm gonna go enjoy my L20B now twofinger_salute.gif

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From my Oct 13 post:

Man this isnt hard at all.

This is DIZZY related proplem!!! Esp in POINT vehicles. Rarely does a coil or ballast resisitor go bad. Esp the stock spec ones. Unless soembody swapped them out with mismatchset.

 

Does it spark or not at the end of the wire comming out of coil????????

If NOT ck the point gap. gap it. Is the condensor wire isolated correctly?????? make sure that screw dont ground out the points inside.

If condensor was replaced try the old one again also. I though the l20condensore were inside the dizzy cap.BAD Condensor will run at idle what I have seen but fatster you go the more it will cut out!!

 

 

OK maybe run the old ballast resistor.

Today I thought shit just wire brush/clean the contaks of the screw in post of the ballast and I bet it will fix it.

 

Glad you got it. Most time Like I alwasy say it never the coil.

 

I helped fix a 520 anout 5 weeks ago with same proplem. Just by putting the cap on it would NOT SPARK. remove the dizzy cap the coil would spark. pretty much the same thing. Going electric will eliminate this FOREVER. then if soemthing happens it will usually be more carb related.

 

Bet alot of Datsun have been thrown away due to points!!!!!!!!

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I want to thank this thread from five years ago (and reinforcing clues from a few topics, but mostly this one) for helping fix my 620 this weekend. Great diagnostics - I used them all and ended up replacing the condenser, which was the problem all along. I now know  a lot more about how the ignition system works and why, which I would never had learned if hadn't tried to diagnose myself. Thank-you and I am on the the next challenge.

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It's Hainz... he always remembers the condenser on a points system. The condenser reduces arcing and increases point life. If it shrts internally it's like the points are not opening. Yea Hainz....

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Condensors suck.. Once one goes electric youll never miss a condenser. or the condenser wire not grounded (screwed in good).

 

be watchful of a worn bushing next.

 

I have worn out about 4 distributors so far. bushings or spring fell off or advance lock up

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On 10/16/2011 at 4:43 AM, datzenmike said:

Years from now someone may come across this and say. "So thats how it works. I can fix mine." It's +1 for everyone.

9 years later this helped my diagnose my non starting issue in 10 mins!

 

The only screw which I didnt replace was the hardest to get to and the one that had crumbled away!

 

I have this setup for reference although I think it might be from a 510?

 

https://imgur.com/gallery/7ucWsyv

Edited by frank88

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The picture? is a pre '78 KC or long box 620 truck.

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1 hour ago, datzenmike said:

The picture? is a pre '78 KC or long box 620 truck.

 

Sorry Mike, this is my truck. I'm still struggling with embedding images! Or do you mean that's what it's from?

 

I'm a bit confused with mine because I think we have discussed before how my 76 truck shouldn't have an l20b in it. And when I turned over the coil bracket, it says 510 on it.

 

It's working now anyway 🙂 

Edited by frank88

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Here it was '75 through '79 with the L20B, '74 was and L18 and '73 was an L16. Some overseas markets saw J15 engines in the 620.

 

Pretty much all points, coils and ballasts will be the same for L series engines as they all do the same thing. Why reinvent the wheel for every vehicle and engine? A points 510 coil will work on a points L20B no problem. My '76 710 (with an electronic ignition) has a coil from an '85 720 truck.

 

The truck is over 40 years old and in that time a previous owner may have needed to replace the coil.

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