Arne

So I'm betting that these carbs with the metal damper caps have squared-off float covers, and no drain plugs in the float bowls. Am I right?

I was under the impression that some of the very earliest 240Z carbs had metal damper caps. Not very many, but a first few. The low VIN of your car supports that. I suspect they are original.

I'm not sure where that 300 number came from (I've seen it too, mostly on eBay I think), but I know that I personally have encountered 4 of them in the past 9 months. So I suspect there were far more than 300 Series 1 automatics. I can guarantee that whatever the number was, it is one fewer now, as my car has a Type A 4 speed in it now (which is the proper type 4 speed for an early car).

Yes, but...Some cars that were built as automatics did have one noticeable difference - some of the automatic cars did not have the spot-welded bracket on the right frame rail for the clutch line. This would be a fairly easy thing to look for to see if a car had been converted from automatic to manual (as my car has been). I've found no rhyme or reason to which automatic cars had the bracket and which didn't. Mine (12745, 10/70) did not. At the Canby show I noticed that a very similar car belonging to funz1z did have the tab. Her car is only a few numbers earlier than mine (12403, also 10/70). The automatic cars have a bracket spot-welded to the firewall for the kickdown switch as well. I don't know for certain (as I don't have a true Series 1 manual car to compare to), but I suspect that there differences to the tunnel as well. The automatic selector mechanism bolts to the top of the tunnel - I doubt those holes and captive nuts exist on the true manual cars. And having done this conversion myself, another thing that is different that seldom gets changed is the wiring harnesses. Both the dash and engine harnesses for automatic cars are different than for manual cars. So if you are really concerned about originality, be aware that converting to a manual in such a way that no one could possibly know is harder than it sounds. On the other hand, if you are not planning to restore it to concours original quality, converting an early car to a manual transmission is not hard. I wrote a tech article on the process after I did mine - Series 1 240Z auto to 4 speed swap

The "official" build date should be stamped on the door jamb data plate. That said, if you look at the rergistry at zhome.com it looks to me as though that car would most likely have a date of 9/70. As to whether you call it early or not, depends on your definition of early. It is definitely a Series 1 car, about mid-way through the Series 1 production run, number-wise. Whether or not you consider it a '70 or '71 model year is also open to debate. In many states, the dealers had a bit of leeway back then as to what year they titled a car as. For the early 240Z, the more important part seems to be whether it is Series 1 or not.

Bob, when I read your story in the e-mail, I wondered about the Heli-coil route. Personally, I'd feel better with it drilled for a separate bolt and nut. That's assuming that both surfaces that the nut and bolt-head seat against are machined and parallel. I can't recall off-hand if the other surface of the threaded part is machined or not. Just out of curiousity - were/are you running bump-steer spacers?

Oh! Regarding the freeze plugs - I've always put them in dry.

I too have used Form-a-gasket. Seals well, holds gaskets in place while you get things in place, and cleans up nicely down the road. I HATE silicone/RTV sealant!

Sounds stock to me. Intake ports on these cars were always round, and square exhaust ports were used through '76 or so.

Well, we probably need more info. Is it a 240Z, 260Z or 280Z? If it's a 240Z, you could try looking through the registry at ZHome.com. In fact, since you didn't fill out the Location field in your profile, we don't even know if you are in the US, or wherever. Or whether your car is a US-market car or not. Or you could simply post the VIN here and maybe we could help some.

I had my flywheel resurfaced a couple of months back, it was $38. Highly recommended if you're installing a new disc.

Agreed. Un-burnt fuel is almost always the cause of explosions like this. Don't fiddle with the timing until you know the carbs are right.

Looks like an aftermarket switch someone has added. You'll need to trace the wires to see where it goes, but my guess is that someone has tried to add a manual switch for the cold-start injector. Exactly how they've wired it is anyone's guess.

I can't believe that you type slower than I do, Will! I didn't think that was possible!

The condenser on the alternator is there to eliminate alternator whine in the radio.

Welcome. Lots of help available here. So much so, that it's worth learning to use the search feature to find answers to common topics like this. Best buy on floor pans is at Zedd Findings in Canada.

Also, early 240Zs (built through sometime in Jan. 71) had wheels indents in the spokes instead of holes. From then on, all 240Zs had holes in the spokes. I may have a spare later one (with holes) in a week or two. As Carl mentioned, they are not that difficult to restore, I just cleaned mine up a few weeks ago. Mine - http://classiczcars.com/forums/showpost.php?p=178322 One of the threads on restoring them - http://classiczcars.com/forums/showthread.php?t=21485

No, you're right - electronic ignition has nothing to do with it. When I researched this for my own diode, as well as for the plug-in adapter, I found several sources which indicated the diode was necessary only for 240Zs. Some put it the other way, that it wasn't needed for 280Zs. I don't recall any off-hand that actually mentioned 260s, so I'm not certain about them.As to the reason it's needed - all cars with alternators need a diode. In the old days, generators make DC, which is what our cars use. Alternators on the other hand, make AC, which cycles back and forth. The diode is necessary as part of what converts the AC to DC. Sometimes the diode is within the alternator itself, sometimes it is somewhere else in the electrical system. As best I can determine, in the 240Z system, the diode was inside the alternator. But the ZX alternator doesn't have one in it (ZX's must have had one in the wiring somewhere), so one has to be added.

Lots of things I don't know. But I tend to go overboard on things that I'm interested in...

You do have to by-pass the external regulator, but I'm under the impression that you might not need the diode on a 260Z, only 240Zs. Could be wrong though...

I don't know much about flat-tops, but I'm wondering if the float level is too high, or the float is stuck, sending fuel out of the float bowl vent hose? (Do flat-tops even have float bowl vents?)

The lower red section (amber in the rest of the world) should be a turn signal/hazard only. The upper/outer red bulb is brake and tail. I can't recall if the upper/inner section is also brake/tail, or tail only. I've seen wiring diagrams that show them both ways. So if the three bulbs back there are a pair of dual filament bulbs and one single filament bulb, the single filament goes in the lower, and the two duals go in the upper. If you have one dual filament bulb and two singles, the dual goes in the upper/outer, the dimmer of the singles goes in the upper inner, and the bright single goes in the lower. On a related note, the taillight bulbs and wiring are another way that the US Series 1 240Zs differ from the later 240s. Series 1 cars have tail lights in the upper two bulbs, and all three red areas serve as brake/blinkers. The later 240s are almost the same, but the upper inner bulb is tail light only, and does not server as a brake/blinker.

Chances are that the explosion damaged some of the baffles in the muffler. Check the muffler shell to see if it looks swelled, also. My best guess is that other than damage to the muffler, the car is probably safe to drive.

Seems to me that the maintenance schedule called for the diff lube to be changed every so often, regardless of mileage. So the presence of an RTV sealant wouldn't be all that surprising to me, even on a low mileage car. Assuming, of course, that the previous owner followed the maintenance schedule. As for the markings, it wouldn't surprise me to find that the gears were marked somehow during assembly and setup.

On my P79 head the extra holes are not drilled through. I left them empty and all is fine.