Technical Department - Ignition Problems - Grounding Datsun's Breakerless L-Series Distributors

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

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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Last updated on Monday, 04-Oct-2004 09:39:51 PDT

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