'75 280Z - Starts and Runs, Shuts Off after 30-60 minutes

[Bigz Zee]

1975 280Z, I bought it two months ago and I just starting to sort it out.
The car appears to be fairly stock, in other words, not heavily modified.
The previous owner does not have a lot info about the car, it seems he bought the car from someone in Mississippi who did the rebuild and body work.

The car starts and runs fine, but it has konked out on me twice.
After the car is warmed up, and having driven it for 30 plus minutes, if I drive the car hard, it's starts to stumble, and then it will turn off as I shift gears.
When I put it back in gear it runs again. I can keep it going that way for 10 minutes or so before I have to pull over and park it.
So I pull over, let it cool down for 15 minutes, then it starts right up and runs fine.

The engine temperature is nominal during operation.
The points were replaced with electronic ignition. Pertronix ?
The coil is an Accel Super Stock.
Spark plugs and wires appear new and in good condition.

Here is a photo album of the car, with pics of the engine bay and close ups of the distributor and coil.
https://photos.app.goo.gl/mPAoGeADxL8qoH3U7

Edited June 14, 2020 by Bigz Zee
Posted before finishing

[siteunseen]

I've had crud inside my fuel tank that would let them run intermittently like that, it's a real pisser. Put a clear filter coming out of the tank and see what you have.

Good write up here, http://www.atlanticz.ca/zclub/techtips/fuel/g3filter/index.htm

[Bigz Zee]

A very good suggestion. See attached photos.
There is crud in the filter and it also appears to be leaking fuel.
The previous owner said the person who redid the car coated the inside of the tank, and suspects that coating is a weak point in the fuel system.
Maybe replacing the tank is the way to go. What do you think?
And how would I know if the crud made its way to the injectors? 

Thanks

[siteunseen]

They used to cost about $10 so for maybe $15 I'd buy a new metal filter that goes up front before the fuel rail, passenger's side fender. Hacksaw it in half and see what you find. I very much doubt any crud would get past that filter and make it to your injectors. 

The tank liner I used was Red-Kote and you would see red slivers in that rear clear filter. That looks more like trash to me? Anyhow it shouldn't leak if you have it right out of the tank, before the high pressure fuel pump. You wouldn't want that after the fuel pump's 35-ish psi output in my opinion.

Others will chime in later about your ignition overheating. That's the 2nd issue you could have off the top of my head. Good luck. 

[Dave WM]

Next time it will not start, have a spare spark plug handy, plug the center lead of the coil to the spare plug, lay it on the strut tower so you can see it, and crank to see if there is a spark. You need to diagnose the issue to spark or fuel before going deeper.

[Bigz Zee]

Thanks Dave. I was thinking along the same lines, is it fuel or spark. I like your idea, I'll try it later today.

[zclocks]

This is a little piece of data , but are you sure this is a 75? It would appear that you have a 77 or 78 280z. Check the drivers door jam for production date. 

This will make a difference if your looking for data or parts/ location. BTW very nice car.

 

[Zed Head]

7 hours ago, Bigz Zee said:

 if I drive the car hard, it's starts to stumble, and then it will turn off as I shift gears.

The points were replaced with electronic ignition. Pertronix ?

In case anyone missed it.  It has a Pertronix under the cap, apparently.

Another sign of ignition problems is the tachometer needle behavior.  Watch the tach needle when the problem happens and see if it's following engine RPM or if it's acting crazy.  If the engine dies and you're in gear the needle should still follow RPM as you coast down in gear.  If it does you have spark, but no fuel.

[Bigz Zee]

The VIN in windshield matches data on the door jam and the data on the plate on the strut. Engine number is not a match.

I'd like to find the person who redid this car, so I can get the details on what it is and what was done.

Zclocks, what are the pieces that make it look like 77 or 78?

[Bigz Zee]

Is this a stock transistor distributor or Pertronix? I'm new to this car and may have provided some incorrect info about the dizzy

[Zed Head]

4 minutes ago, Bigz Zee said:

The VIN in windshield matches data on the door jam

What is the Build Date?  It's on the door jamb plate.

I think that 75 only had one fusible link block, not two.  Your car might be a 76.  

[Bigz Zee]