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Pedastal = distributor mount with the tang that has the 10mm hold down bolt. also known as dizzy mount.


ground the case of dizzy to the dizzy mount(pedastal)



I wonder if you go to Radio shack and buy a bottle of quick freeze and spray the module whn this happens if it goes away.


maybe take module off and clean the 2 connections there. the grn red wire.


where does the other end of the ground to the pedestal go?


so the distributor affects coil spark?


i would try the quick freeze, but it usually starts after it dies.

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Quick Tech Tip: Ignition Problems - Grounding Datsun's Breakerless L-Series Distributors

By Kelvin Dietz


If you haven't already done it already, make sure you have your breakerless distributor grounded to the chassis. Datsun originally provided a .250 male spade connector under the vacuum can screw for grounding. Use it. Yes, I know it's an aluminum case bolted to an aluminum pedestal, which is all firmly attached to other metal bits. Why would you have to add a ground wire from the distributor to the chassis? I'm guessing Datsun did it for a reason and I've fixed three cars with odd electrical problems, including one of mine that got by with no ground wire for 3 years.

A few days ago that car was running badly again. It sure felt like the same problem - tach was jumpy... missing all thru the rev range - but we'd just added a ground wire a few weeks earlier!


We pulled the dizzy and swapped black boxes. I've honestly never had a black box go bad. Dozens of these distributors have gone thru my garage. It seemed I finally had a bad one. Swapping the black box fixed the problem.


I took a look at the old box sitting on my bench. The back of it was very dirty and the aluminum quite oxidized - about what you would expect after 25 years. We decided to pull the distributor back out of the car and clean the mounting area on the distributor as well as the back of the original black box with a wire brush. We then reinstalled the old black box and buttoned the whole thing back up. And guess what? The cleaning worked like a charm! The car ran great with all of the original parts.


My guess is most of those "dead" black boxes aren't. That box needs a good ground and after all those years there is enough corrosion to lose that.


Tach jumping? Car running like crap? Give it a try. It just might be the answer.

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Not to thread hijack but My rigs always make it home. But all are L motors. They havent really broke hard in a LONG LONG TIME. Dome a headgasket maybe ayear or year and a half. but that is not a hard break for me. 3.5- 4 hrs I was rolling again.



I swear the top part of the T on a matchbox was the B side


really? i read here: http://datsun1200.com/modules/mediawiki/index.php?title=Matchbox_Testing

that its the stem of the T.


how can i b certain?

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ugh. still doing it. :hmm:


but, when it wouldn't start for 10 minutes i turned the ignition off and took the key out. Then put the key back in, cranked it, and it started up no problem and made it home.


i'm sure you guys are tired of hearing about this. it's so frustrating cause when its running it runs excellent. but then the spark just decides to take a break. wtf...

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The bottom of the tee is where my positive side of the coil wire is on both my trucks, the top of the tee is the negitive side of the coil, and both my engines are L20b blocks with w53 heads or at least going to be as soon as I get the other head back from the shop, thanks Skib, had it ported for the dual SU intake, and had to get rid of the brass valve seats as my foot is to deep into the pedal all the time. :lol: wayno

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  • 1 month later...

hey guys. so i have an update.


I replaced the Ignition Control Module on my distributor 5 days ago and she hasn't given me any trouble since. I'm pretty sure that was the problem.


and now on to other things.


thanks for everyone's help.:thumbup:

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I just thought of this in case you have trouble in the future again with the starting, I found out there is an extra wire that goes directly to the coil in the 71 521 wiring harness, this wire is to supply the coil with power in the starter engaged mode(while you turn the engine over), I had trouble starting my truck in the morning because this wire had somehow been disconnected, so I found out if I jumped the positive side of the coil directly to the battery, the truck would start right away. Then one day I seen this wire, I think it was a black wire with a red line, I looked it up in the wiring diagram, seen it belonged on the positive side of the coil(it bypassed the ballist), I reconnected it and all my starting problems went away, I also have the matchbox distibuter. wayno

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  • 1 month later...

They are, but boxboy has a source in Singapore that he shared with me and I ordered 2. they took about 2 weeks by air mail which i thought wasn't too bad.

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  • 2 weeks later...

small update. replaced oil pan with correct 521 pan cause it was leaking oil.



and here's the old(wrong)510 pan. worst pan i've ever seen. motor was sitting on crossmember. it was all f'ed up. how does that even happen?





was totally stoked to stop the leak, but then found out the motor is leaking form timing cover too. :no:



good thing timing gasket kits are dirt cheap. On the upside, she runs soo much smoother from the engine not sitting on the frame.smile.gif



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  • 3 weeks later...

I've been having problem after problem with my 521. When I read your ignition problem, I'm curious if when it shuts down on you, is the coil HOT to the touch. We've had this problem with British cars at my fathers shop. They start back up again a few minutes later when the coil has cooled. I have a hunch that's what it may be, but you have the right resistance in your coil so I'm not sure anymore...

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