Mark Maras

While the fuse block is out, look for corrosion and heat damage at the wire connections. It's not uncommon to find melted plastic due to poor conductivity. Caig DeoxIT is a good product to use on old elec. connections.

A four bolt, splined hub and nut adapter, spacer? Bolt on Rudge hub would be my guess. Never heard of one but it looks like there could be room for the four lug nuts behind the wheel center.

Along with the float bowls and intake (I don't think the problem is with the intake temp), measure all the fuel line temps (every foot or so, return lines too) under the hood, including the mech. f. pump if it's still there, and go as far into the tunnel as possible. Remember, the boiling point of fuel is lower than water. The results should be interesting.

Don't remember what temp your thermostat is rated at but I wouldn't be a bit surprised if your temp gauge ran at 3/4 and the coolant temp was fine. Good thing to know. You could double check the actual coolant temp using a cooking thermometer in the top of the radiator. Pull the rad cap before it warms up. VOE I haven't measured the temp on various engine compartment components but 400` seems a bit on the toasty side for an intake manifold. It was the intake manifold temp you measured, right? Just want to be sure. Have you measured the temp on fuel related components yet? I'd start with the float bowls and work my way upstream. One reading of fuel related components at operating temperature and another reading when the gremlin shows up could pin point the problem area, based on your findings. I do think it may be time to start looking for a method of venting under hood heat. Late 280 louvered hood would undoubtedly help or one could louver the access hatches on either side of the hood. I seem to remember in the past you tried pulling the hood latch and it did make a difference.

The temp difference may not be as great as one might think. My yellow Z with a black interior no AC and no louvers was an oven in the summer time. A lot of the heat came from the tunnel.

What! No Cheech and Chong?

@Zed Head Damn, I just have to know. How much of the shed? is still standing and have the blackberries taken over yet? I hope someone (not me, according to Kathy and the Clackamas County) gets it before it's too far gone. Yellow Z's have always been my favorite. That previous thought brings to mind a very underhanded way to get the owner to let it go. Not that I would suggest anyone do it, but, (hypothetical scenario) if he had too many inoperable vehicles on his property, (he did when I was there) one could call Washington County and point out the fact to them. Voila! Motivation to sell. Back at ya ZH. The ball is now in your Washington County side of the court. Are you beginning to hear THE VOICEZ? They're calling to you.

Type 1. I like the way the stripe follows the hood contour.

Cap'n, should you want to give it a try, www.circletrack.com has a write up on the subject of alignment using strings. Looked quite interesting when I read it a few years ago.

IM(not so humble)O, That's how "They" start out ruining great cars. "They" (pick any manufacturer) start adding extraneous B.S. instead of quality and design tweaks to improve the car. Eventually "They" end up pushing a bloated "Jabba the Hut" on the masses and wonder why the appeal is dwindling. Thanks, I'm feeling a little better now.

Vinyl tops and sun roofs on Z's fall into that category of, "Just because you can, doesn't mean you should."

Not a dumb question at all. Add me to the list of people who don't understand why. Some Z owners have used the early Mazda RX7 electric pumps. It reportedly is quite good, inexpensive and much quieter than most.

I believe he replaced the needles.

Welds look like the wire speed was too fast and or the tip was too far from the weld. I have to get really close to the weld with the gun on my Eastwood 135.

Define, "stopped working." Won't engage? Won't disengage? Did the throw out bearing slide on the collar easily when you replaced it? Worn collar causing the bearing to bind?

Sounds like the float level is too low in the rear carb. Fuel level should be 1/16" below the jet at 2 1/2 turns down.

Stick your finger in the tail pipe and collect a sample on your fingertip. That and a sniff test will indicate what's coming out of the engine. I think I'd take a look at the plugs and do a compression test too.

You may want to consider pulling the engine. It really is quite easy. The oil pan can be removed (my experience is 240Z) in the car but it can be a BIG PITA to break loose. As I recall, when removing the pan, the crankshaft has to be turned.

Thanks for sharing. Fascinating. looks kind of fragile although it probably isn't. 14:1 compression is impressive. I'd like to see the Harmonic Drive internals. Kinda reminds me of the auto articles from the early 1900's. Inventors were everywhere and tried almost everything they could lay their hands on. To control engine speed, the cam lobes were cut on a compound angle. They would slide the cam endways to control engine speed. Variable valve lift and duration. This was prior to butterflies in the carbs to control the intake flow.

Are the carbs flat tops or round tops? If round tops, 4 (early) or 3 screw (late)? The car, as described, shouldn't exist. Unicorn?

What leads you to believe it's a 260? EFI or carbs?

Yup, it's worth a try. I've seen ones with a couple of rusty lobes that were cleaned up and worked fine. That one would be a challenge but you'd know after cleaning a lobe or two if it was worth the trouble to finish it.

Finish tuning it and drive it. I've heard of a lot worse things than this and everything turned out fine. I had one old engine that ran fine when I fired it up after years of sitting but was a little low on compression on two cylinders. A bit of blue smoke in the exhaust, slightly oily plugs in those two cylinders. After a few hundred miles, everything cleared up. I think those two cylinders had stuck rings and or rusty cylinder walls. Marvel Mystery oil in the cylinders prior to starting may have prevented more problems. Evidently the rings became unstuck or the rings re-seated. The engine lasted for years with good power and no problems. Enjoy it.

Hopefully, no damage. A compression test might ease your mind a bit. Other than that, watch for symptoms like blue smoke from the exhaust, oily plugs, gas in the oil, etc. Install a new set of plugs so you can get a good color reading and dial in the carbs. I think the engine will be fine. Good luck and keep us posted.

Eyeballing the fuel level is close enough. I don't recall how many turns of adjustment the mixture screws have. My original 4 screws had adjustable stops below the mixture screws. The stops you're referring to were probably adjusted down farther or removed to allow more mixture screw adjustment. 2 1/2 turns down and the fuel level (floats) set 1/16" below the jets is what you're shooting for.