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upgrading distributor on '74 automatic 260Z


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Hello, Everyone: I did a search, but I guess having an "oddball" has its disadvantages. For those that don't know, the '74 automatic uses a rather unique dual magnetic pick-up distributor which allows for "advanced" timing when the engine is warming up and "retarded" timing when at operating temperature.

 

I have attempted to run a manual distributor using an MSD 6A and its magnetic pick-up (purple and green wires) system, but the car only ran once and died (engine worn). LSS, I don't know if the car never ran again because I did something incorrectly or if the worn engine (timing set) was the cause of the vehicle never restarting until after the repair.

 

Does anyone know how to reliably bypass the stock ignition module?? The one I refer to is the one mounted in the passenger footwell in the car. Does anyone have experience a Mallory Unilite/Stock Manual Distributor/MSD box using this configuration as your "starting point?"

 

When the engine goes back in the car this time (after its current rebuild), I won't be running the thermal relay or temp. switch, so the module may never get the information necessary to trigger the "retarded" pick-up.

 

Sorry for the rambling, but there's a lot of background information here to cover in order to get the most accurate responses. Any information would be greatly appreciated. Thanks for your time.

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I would try running a zx e12-80 equiped distributor. You'd have a self contained ignition system. You'd only need the distributor, coil, and a 12v power source. I ran this setup in my 74z, but it was a manual trans. As far as bypassing the module in the footwell, I would remove it and test the wires for a "hot" 12v source and cap them off to prevent any shorts.

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Hi, I am in the same boat as you and all I did was unplug the 2 wire plug that feeds the temp switch. I am only using one pickup coil now and the car runs fine. I was going to put in a 260z manual distributor but it only has 2 main wires and the auto distributor has 3 main wires. The 2nd pickup coil in the auto distributor comes on when the car is cold to retard timing by 7 degrees and supposidly turns off when car is warmed up. I ran my car with it still hooked up after my 4 speed conversion and everything seemed to run well with the factory 2 pickup coil unit too.

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Thanks for the information. I actually got the thermostat housing (brand new) from an earlier car ('71 or '72 I believe) and it doesn't even have the threaded hole for the temp. switch, anyway, so I was planning to run without the switch altogether. That was another thing I was curious about, coincidentally, so you actually answered two of my questions!!

 

I know that switch sends temp. information to the emissions control system also (I believe to run the EGR system), so I was wondering if that might cause any issues after warm-up, but I doubted it would....it just helps to have someone who has "blazed the trail" before me confirm my suspicions.

 

I probably will do exactly what you're doing now, as that represents the easiest option in the short term. Sounds good. Thanks again.

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I too asked your very same question not to long ago and got no responce so I had to take matters into my own hands. I only unplugged the 2 wire lead coming off of the temp switch and car runs fine cold or hot with no issues. I ran into a different problem that you might want to act apon. My starter would not always engage. Every once in awhile I would just get a click. I replaced the electrical piece behind the ignition switch and had the same problem so yesterday tracked the problem down the the ignition relay. I called the Nissan dealer and there are only 4 igniton relays in the country for the 260z and now there is only 3 as I bought one and would recommend you buy one as well. It was only 40 dollars. If you are going to use the wiring system I would recommend this. Good luck on your project.

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Thanks, zedsn:

 

The issue of parts "disappearing" from stockpiles is the sad reality for all of us. That's something that I hadn't actually considered in this case, so your tip is very timely. Also of general interest is that I have found in the past that prices will often show up on dealer computers for parts that no longer are available, and only until a request from the dealer comes to a warehouse for a non-existent (no longer available part) part does the inquiry reveal the situation. Of course, that just multiplies the disappointment, as up until the time the "word" comes in, the customer is under the impression that he/she "dodged a bullet" and found remaining stock. I wish Nissan (or at least my local dealer) would fix that.

 

Anyway, thanks very much for the tip. It looks like I'm headed to my local dealer to buy one of the last few.

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