Some of you saw my post a couple days ago asking about swapping an auto to a manual on a 78 280z. Welp, I got to see the car in person today, and I decided to roll the dice on it. I've been on the hunt for a couple years and this one checked almost all the boxes. Time will tell if it was the right call...

PROS:

1. It runs and drives and stops. The gas is definitely varnished, I could smell it bad. But it still ran, with a little miss here and there. Moved around just fine and went through all the gears.

2. The price was fair. I knew getting an AUTO car would help keep the price down.

3. Car appears to be a lifelong California desert car. Rough on the paint, but great for rust prevention. Doglegs and lower fenders are in great shape. Floorboards and subframe all appear very dry. Battery tray has surface rust, but I've certainly seen worse. Rear hatch area has a few bubbles, but not rotted. The cowl has a pinhole and bubbles located right above that foam block that sits underneath it. As you all know, it's not a matter of IF a Z has rust, but rather how MUCH rust it has. Pretty pleased in the rust department.

4. No side molding! No holes in the sheet metal. I like that.

5. Could it be a 70K mile car!? No way! I'm probably dreaming. I'd be shocked, but maybe. Pedals don't appear worn down. It appears largely stock and un-modified, apart from the wheels. Take it with a grain of salt, but the owner said they bought it from a neighbor whose wife passed away, and it was her car. Who knows, but I would be thrilled if this were the case. Let me know if you have any ideas how I might know.

6. The engine sounds quiet. The usual tick tick of the EFI, but I was pleasantly surprised, even with junk gas. With the cats and the muffler, I can barely hear the exhaust note. Very quiet overall.

7. POSSIBLY 90% original paint. Radiator paint code is present (code 306) which matches the exterior. And I don't see any tell-tale signs of a repaint (overspray onto rubber molding, gas tank, door jamb placard, etc. This makes me happy because I know you can hide a lot of bondo with a respray. I can visibly see all the right "seams" and joints where body panels come together (rear valance, dog legs), telling me they haven't been smoothed over with filler. I say 90% because the drivers rear quarter definitely had some work done at some point. I see evidence of bondo on the bottom lip of the rear quarter. Can't have it all, I suppose.

CONS

1. No smog certificate. Seller wasn't willing to hassle with it. Having met the husband/wife sellers, I don't suspect any mal-intent, they just didn't want to hassle with it, and knew it likely wouldn't pass. They've had it on non-op for 5 years, never actually drove it, other than around the block. They had several other people lined up willing to buy it as-is, no questions asked, so I knew it'd be a dealbreaker if I put up a fight. I knew if I didn't buy it, it'd be gone within hours. So I'm rolling the dice here, because I'm in CA and it's a 78, which means I'm going to have to smog it. I know, dumb.

2. It's an automatic. Positive spin, the autos weren't as abused as the manuals:) I'm planning on converting to a 5-speed eventually, so this isn't too big of a deal.

3. Paint is clearly shot, but I'll be leaning into the "patina" look anyways.

4. Drivers door hinge lost its detent stopper, overextended the door, and bent the corner. I think I can work it back into place.

   Anyways, here's a few pics! I'll keep y'all posted on progress, I'm sure I'll have questions...😄

https://share.icloud.com/photos/057GXCdBmlMhz6-XjN5ifnOGQ

Edited May 31May 31 by kcpope

4 hours ago, kcpope said:

but the owner said they bought it from a neighbor whose wife passed away, and it was her car. Who knows, but I would be thrilled if this were the case. Let me know if you have any ideas how I might know.

Congrates on your car, it could well be a 70 k miles car as it was a wife shopping car for xx years? Find out how many years she used the car.

Another clue is the worn pedals.. they are not? That's a good sign.

I got myself a 119000 km car in 2013 and i took a look at the original "scratches" in the cylinders and they were still perfect. I KNOW the car has only 119000km or 73968 miles on it. How i know, the last owner before me was a RDW (see www.rdw.nl) employee! And they register every year the milage (Or in this case the km on the car)

If the scratches (hohning?) in the cylinders are very nice looking it can be a 70k miles car!

I have some pics in my topic: restauration of a datsun 280zx slick roof 2+2 1979, here on the site..

4 hours ago, kcpope said:

I'm planning on converting to a 5-speed eventually,

When converting to 5 speed (or 4 speed) you will need also a differential with the right gear.. A auto-diff has 3.3:1 and the manual has a higher number 3,7 or 3,9:1

That's pretty clean. Looks like a good base

Service manual says that auto and manual were both 3.54 in 1978. The difference is R180 versus R200.

I was thinking about this the other day - I wasted money on getting my engine to run right because I didn't check injector flows. When I finally did I found that they were unbalanced, some flowing what looked like 10 - 20% less than others. If I was starting where you're at I'd do that and replace the injector seals. Vacuum leaks and low injector rates can cause misfires.

Nice, congratulations on your purchase. I like the automatic hadn't been driven to hard, totally agree.

Get some covers for the fusible link block. They're cheap on ebay, https://zcardepot.com/products/fusible-link-cover-oem-260z-280z-74-78?_pos=1&_sid=dafc32314&_ss=r

Might want to get the right links too. White is not an option. Looks like someone cobbled up a DIY link.

Here's a fairly quick task that helps a lot. Cleaning the electrical connections makes them run, idle much better.

https://www.atlanticz.ca/zclub/techtips/electricalconnections/index.html

Thanks everyone for the input👍

Yes, as much as I want to dive into other things on this car, first order of business has to be getting it tuned up enough to pass smog.

I'll research how to check injector flows and clean up the electrical connections as mentioned on Atlantic Z. The gas is clearly varnished so I'm going to start by draining that, then maybe dropping the tank and taking a peek inside.

Small victory though, I couldn't resist doing something about that bent door corner. Massaged it back into place. Much better.

Edited June 1Jun 1 by kcpope

On 5/31/2026 at 10:13 AM, siteunseen said:

Nice, congratulations on your purchase. I like the automatic hadn't been driven to hard, totally agree.

Get some covers for the fusible link block. They're cheap on ebay, https://zcardepot.com/products/fusible-link-cover-oem-260z-280z-74-78?_pos=1&_sid=dafc32314&_ss=r

Save on shipping and get them from your nearest Nissan dealer! I bought a cover for $11 and some fusible links a couple weeks ago.

Ok, would appreciate input on my “tune up” plan for the engine in order to give me the best chance of passing the smog test.

As a reminder, this engine runs. But based off the paperwork, it has struggled to pass smog in the past. Last time it passed was 2008, after several attempts. It actually idles ok despite obviously varnished gas. Maybe a little stumble here and there at idle, which could just be the rotten gas. We drove it around and it went through the RPM range just fine.

I’m putting these in order of perceived importance. Feel free to re-organize if you disagree.

1. Drain all gas from the tank. Then backflush the fuel line from the engine compartment to the tank to clear any lingering old gas.

2. Remove all injectors and clean them by actuating them them with a power supply while pressuring them with carb cleaner. Check flow rates as Zed Head mentioned?

3. Check for potential vacuum leaks

4. Clean up electrical connections as mentioned earlier re Atlantic Z link

5. Inspect spark plugs. Replace as needed.

6. Check distributor? I’ve rebuilt a 280zx distributor in the past, including those little steel balls that like to vanish. Is that a must here too?

7. Replace fuel filter

8. Replace air filter

9. Change oil with 10-40 VR1

10. Install correct fusible links

Anything I’m missing?

Edited June 2Jun 2 by kcpope

What's the test procedure? Idle only or 2500 RPM under load? Does it have a catalytic converter?

Since the system was designed to pass emissions I would set everything to factory specs.

Ideally you'll be able to take it out for a good Italian tuneup or two before the test.

Test procedure:

The car runs on a dyno at two steady but loaded conditions while a probe in the tailpipe samples the exhaust. The two sequences are the 50/15 test, 50% load at 15 mph, and the 25/25 test, 25% load at 25 mph. At each mode the probe reads HC (ppm), CO (%), and NOx (ppm). Higher-load mode tends to surface NOx issues, lighter mode surfaces HC/CO issues.

Yes, full factory exhaust system is in place, including the cat.