Mark Maras

Any change in the engine performance when it was tapping?

I agree, IF the drum brakes are well maintained.

I think I see some poor, lumpy bodywork in the right quarter panel. The raised body line that runs the length of the car disappears at the wheel well and appears again towards the rear. The left q. panel appears to be more original. The hatch seems to fit well. Same for the right door. The left door fitment is off. The uncracked dash is rare. Probably means that it was covered well over the years. Looks to be a good buy, IMO. I'd take it back to the orig. color.

A vacuum leak would add more air to the mixture. The normal symptom of a vacuum leak is a higher RPM at idle. Remember, anytime you suspect a lean condition, you can ease the choke on and see if performance improves.

Still looks too lean. The white porcelain should be a tan color. Does it still run rich at idle and load up (turn them black) the plugs? I'm assuming the pictured plug had little idling time. Please confirm.

@jalexquijano Sitting here thinking back to what I believe was the original problem, which was the plugs loading up and getting sooty at idle, I visited the "WayBack Machine" and remembered something from long ago that I ran into. Another possibility that would cause that condition is a barely leaking needle(s) and seats and or excessive fuel pressure. Theoretically, a less than perfect (but not belching fuel terrible) seal can allow excess fuel to bypass the needle and seat and raise the float level at idle when the engine is using the least fuel, causing a rich mixture. The longer it idles the higher the fuel rises in the float chamber. As the engine rpm's and load increase the excess fuel in the float chamber is used and the fuel level returns to normal. Did you ever notice plugs 1, 2, and 3 being lighter or darker than 4, 5 or 6? A possible sign of one carb leaking. Kind of a shot in the dark but your symptoms seem to relate to this. It 's not that uncommon in carbs. Thoughts?

According to ZTherapy's Spotters Guide, the flat tops started in June 1972 and lasted through the 260. 1974.

Check out Craig's List, Portland Or. There's a couple of Z's that may be what you're looking for.

In the overhead pic of the engine, note the discoloration around the battery compared to the opposite side by the brake master cylinder. Discoloration doesn't look too bad until you pull the battery and find the fender well, firewall and the frame are all severely compromised by rust. If they are still there, that is. Z's have some areas that are prone to rust. When looking for a Z, find the best "rust free" chassis that you can afford. Period. Mechanical bits on the Z's are well built and easy to repair. Can't say the same for the bodies.

You don't avoid it, it's part of the tuning process. I would suggest that while you're idling in traffic, keep the RPM's up at a happy idle, maybe around 1500 RPM's or a little more. Or, if the engine starts easily when warm, shut it off when you have to sit and idle. See if that will keep the plugs from fouling. The needles, springs, float level, could cause the sooty plugs at idle. I think you had SM needles, what color springs are you running? I know you set the floats but you wouldn't be the first person to have to go back in and tweak them a bit. I won't be convinced that they're right until you pull the domes and pistons and tell me what the fuel height in the jet is at 2 1/2 turns down.

No

@Redwing

Go to 2.75 and check the plugs again after a few days. Small incremental changes. Try to keep the drive the same between plug checks. In other words, if the plug readings have been with, say, 1/4 traffic and 3/4 highway miles, try to keep the percentages the same. Don't read the plugs after idling in traffic one time and after highway miles the next. Try heavier wt. oil in the carbs and see if it helps throttle response. Heavier oil shouldn't affect the idle.

Yeah, too lean. The color should be light to medium tan, not white.

Many members have reported using 1993 - 2002 Kia Sportage weather strip. Some of the Z weather strip is a bit too hard or over sized and prevents the door from closing easily. Occasionally requiring a door adjustment.

Some years ago I read about owners of Oregon vehicles with branded titles, registering them in Washington and then back to Oregon. Seems in the transition back to Oregon, the "brand" on the title would get dropped. The car then had a clean title.

I had the same problem with paint on my 260. I used a HF wood chisel to scrape it off. I was amazed how well it worked. Using light pressure, the paint flew off in a cloud of fine chips. Use eye protection. Paint chips are sharp.

If it is a 71, I have the harnesses out of a late 71.

What an amazing ball of worms. Looking on the bright side, if all the fuses are good, at least there are no short circuits to worry about. A replacement harness might be the best way to return everything to original. You'll also need a multi meter and a good wiring diagram. Don't let the magnitude of the project overwhelm you. Take it one circuit at a time, then move on to the next. Tips; Always check and start at the power source and follow it. A length of wire with alligator clips is useful for grounding and completing circuits. Poor grounds are a frequent gremlin. What year is your Z? Better yet the VIN #. Maybe a member has the harness(s) that would make the job easier and possibly give you a starting point.

What a great pic. Jim II, I absolutely love those wheels.

If the 3 in 1 is thicker than the ATF, try that. Personally, I'd throw some 30 wt into them just to see what difference it makes, then I'd try 20 wt. I suspect one of the reasons that there isn't one wt. oil that works for everyone is wear (increased clearances) in the carbs. In the many posts I've read on the subject of SU oil, The opinions run from A to Zed. Racers that run no oil to a gentleman that used 80w-90w gear oil and swore it was best. Don't be afraid to experiment.

Those look lean for 2.65 turns. Richen them up a bit. Perhaps 2.75, drive it and check the plugs again. Also try the thicker oil. Perhaps that will help with the low RPM stumble. That said, I suspect that your floats may be set a little low. I know you don't want to hear that but we've all struggled with getting the floats right. Have you pulled the domes and pistons to see if the fuel is about 1/16" below the top of the nozzle when the mixture screws are at 2 1/2 turns? That's where the fuel should be when the floats are set correctly.

You would think so because the needle is moving up allowing more fuel but in fact the piston rising too rapidly causes a lean condition. Piston goes up increasing the venturi size, at the same time air speed past the fuel supply slows down and doesn't pick up as much fuel because the engine is at low RPM and isn't pulling as much air. At least that's the way I understand it. There are undoubtedly better ways to explain it. How do your plugs look and what wt. oil have you been using?

More thoughts on oil wt. If you're using thinner oil than 20 wt., you may want to try 20 wt. or even thicker oil in the SU's. The higher viscosity oil will prevent the piston and jet from rising too fast, preventing a low RPM stumble. That seems to be the opinion of most clubs. Personally, I always used Dexron ATF and never had a low RPM stumble but the higher temps in Panama could add to the problem too. Anyway, It sounds like a fun, cheap and easy, but valuable, afternoon project. Try 3 or 4 different weight oils in the SU's. Take it for a drive on the same route and let your butt dyno tell you what she likes. Oh, and be sure to share the results.

No clog. If pulling the choke instantly gives you more power, (the engine is warm, right?) Increase the mixture from 2 .65 turns to 2.75 turns and try the same route again. I still want to see the plug colors. You could still have one carb lean and the other rich. Also what weight oil are you now using in the carbs?