Zed Head

Probably doesn't matter much. You have an L28 in your car because that's the easy way to get more power. The L24 will probably be worth something to somebody some day. The question is whether or not you want to be the keeper of the block. I'd give it away on Craigslist. Some Z head out there will probably take it and make something good from it. I sold my L28 engine for cheap after I replaced it with a better one. I knew I'd never do anything with it. Take the front cover and thermostat housing and other odds and ends that you can use on your L28 and give the rest away.

Are you sure it's an L24? How does the crankshaft look?

Weird. I did a little Googling and found what looked like an interesting "official" Nissan web site. But it has really bad information on it. Just flat wrong. https://www.nissanusa.com/experience-nissan/news-and-events/nissan-z-car.html THE NISSAN 280Z The next of the Datsun Z-Cars to launch was the 280Z in August 1978.

My learning was that 77 was the 4 speed with a 5 speed option, and 78 was the opposite. There's probably sales literature out there somewhere. Release the Google...

You might swap your rear wheels for the fronts while you have things apart. See if the wobble follows the wheels. Of course, then you won't know if it's the TC rod upgrade or the wheels. Maybe take a for a test then swap if it's still there.

Should have a thermotime switch, with an injector-type plug, and a coolant temperature sensor, also with an injector-type plug, and a temperature sender, with a single wire attachment. Later cars have a fourth switch, for the vacuum advance solenoid.

Actually, heat soak has been a big problem with the 280Z's. We've had some good discussions about it in the past. Although, it's possible that the fuel blends have changed over the last few years and it's not as bad now.

The COVID is giving people lots of free time to spend their money on the internet. That is a nice looking example of the $199 package. Odd that it came with a 4 speed though, I thought that the 5 speed was standard and the 4 speed was a requested change.

Have you checked the resistance at the ECU plug, on Pin 13? There are many possibilities, including a PO "tuning" around a problem instead of fixing it. Could be vacuum leaks. Could be something else. Another cause for popping back through the intake is a flat cam lobe. Hope that's not it. You really need to spend a little time at the ECU connector with the 1980 Guidebook and a meter. It has all years through 1980. Make sure everything is right before trying to fix things. Odds are though that the fuel tweak will still help after you get everything right. So that's not wasted time/money. You should check your fuel pressure with the engine not running also. If it can't get higher than 30 that's a problem. EFI work is just a long list of small things.

The fuel tweak was for the popping and stuttering, not the idling. Are you sure that you're disconnecting the sensor? There is also the cold start (thermotime) switch and the temperature sender in the same vicinity.

Here's 82. The easy way to check is with a meter or continuity tester. The switches close when the condition is met. Top gear, reverse, etc.

They're expensive and that might not be the problem. It's just a possibility. Some of us have found that any ECU from 75-78 will work on our cars. So if you find a cheap one at a wrecking yard it might be worth a shot. It could also be just a wire to your coolant temperature sensor. Or the sensor itself. If the connection gets open the ECU thinks you're in the Arctic. Working on these EFI systems is a process of understanding a collection of small systems and parts. Everything is old and could be failing. It's fun.

Might be running rich. That's how the ECU's die. Run rich, kill engine. If you have a spare ECU it would be worth a quick swap.

The stumbling and bumbling after letting it sit hot sounds like the heat soak problem. Your problem also sounds like a bad ECU. You should still watch your tachometer needle. It will tell you a lot if you look at it.

They're all very similar, changes were probably for emissions. If it doesn't have holes in it it's not a turbo cam. The turbos came out well after Nissan went to internal oiling. A cam with no holes in the lobes needs a spray bar. All of the L28's in the states are "E". Electronic fuel injection. Your main concern with installing a cam is to get good rocker arms on good cam lobes. You won't see much difference in performance between the variations but you can wipe out a cam lobe pretty easily.

I knew I should have looked at that picture closer. Standard Nissan variable reluctor distributor. So, probably the original 1975 ignition module which was the second year of electronic ignition. And maybe a "performance"coil, putting more strain on very old electronics. The module is close to the fuse box, in the cabin. It will have aluminum fins and look very cool and space age. The symptoms sound just like when my 76 ignition module went bad. Rev it up to 3500 RPM, the tach needle starts reading double engine speed, and bouncing all over. Let it die and cool off and it's okay.

Yes, it clamps or compresses the injector in to the hole in the intake. The big rubber ring is where the force is applied to the injector body. It's a loosey-goosey mechanism, not precision.

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.

Horrible! Drilling and tapping looks like the way to go. The shavings can be kept out of the intake easily, and the mount is not a super-precise fit. It's actually pretty loose, it's just a clamp for the injectors.

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.

You will have to run your own wires from the oil pressure switch to the relay and from the relay to the AFM plug wires. Your 77 harness only has oil pressure sender wires. The switch came out in the 1978 model year. Also, if I remember right, the oil pressure switch is normally closed (as the drawing shows). It opens when pressure is built. Your friend who knows wiring will need to know this to make the relay work correctly.

The factory AFM's have stickers with part numbers on them. The ZX and Z TB's look different. A picture or two might help identify them. If I had the car and wanted to do what you're tying to do, I would "unbridge" the AFM pins then start the engine. If it starts then dies, repeatedly, then you'll know that the pump gets power at Start. You can also disconnect the starter solenoid and turn the key to Start to see if the pump gets power. that's actually simpler, but you have to pull the correct wire. If you have Start power, then either of the two relay suggestions should work, but you'll have to learn some basic wring skills. It should be simple to do though, and cheap If you don't have Start power then you'll need to wire in another relay. Again, simple, but takes a little work..

I didn't think that Nissan used liquid sealant on the glass. Everything was preformed rubber. On the 280Z's the chrome strip fits in a groove in the preformed rubber, to help lock the rubber in place. How about a picture of the specific seal, the way that you want it to be? Not sure about what exactly the issue is...

It looks like the PO did a good job of making a variety of parts work well together. Nothing wrong with that, that's what half the people on the forum are doing. I think he just needs a way to get the fuel pump to power up only at Start and with the engine running. Like a normal 280Z. The 77 fuel pump and EFI relay might already be doing the Start function. Maybe running a relay off of the alternator charge lamp circuit could do the engine running function. Like half of the ZX system. Just brainstorming. I'd guess that he's just tired of hearing the fuel pump run when he has the key on, besides the safety issue.

Kind of looks like you're looking for affirmation of a thought. Fill the tank and see if the problem stays. These tanks are known for pinholes in the internal outlet tube. How steep is the hill, and how long is the sustenation?