beermanpete

The wear on the washer is allowing the washer to move too far towards the bushign and compressing it, creating friction. Replace the washers and make sure to use some grease when you assemble it. That should help.

This type of problem is common to any old car, not just the Z. Fuses and fusible links not doing thier job is not the problem. The problem is caused by corrosion which creates resistance. Resistance creates heat which increases the rate of corrosion. After a while there is enough heat to affect the temper of the metal and the spring pressure is reduced and the resistance increases even more. After a while the insulation starts to discolor, decay, and eventualy melt. This happens slowly over a long time. The solution is replacing the connectors with new ones. The large white and white/red wires are in the charging circuit, comming from the altenator, going to and from the ammeter circuit, and feeding the car. Therefor, they must carry large currents so make sure to use connectors rated for at least 60 amps. You will notice the original connectors are larger than the other connectoes in the car and larger than the standard 1/4" wide connectors commly available at the part stores.

The condenser for the points is 0.2 to 0.24 µf. The others are not shown in the service manual but 0.1 µf should work ok.

The 10 amp fuse is a suitable size for that pump. Mallory recommends 7.5 amps. The wide gap in the fuse along with the black spots indicate a short circuit type of overload. Considering this type of fuse failure you might have an intermittent short due to a bare spot on a wire somewhere or perhaps something in the pump itself. If you have a recurrence inspect the wiring.

What size is the fuse that failed? How did the break in the element look? Was it melted wide open and have black/smoky marks on the glass, or did the fuse look ok at first glance and turn out to have a small crack in the element?

Excellent!

Nice. Thanks for the pics.

Good to hear you are making progress. It is alway a good feeling to get past a tough problem with positive results.

Cool. Since you have a 3-wire tach you don't need to bother with the early tach stuff. That is only required for the 4-wire tach. Try the new tach when it arrives. That will likely solve the problem with the tach. Also, you might need the resistor as shown in the diagram for the fuel injected model.

Assuming it is not the auto-trans swap issue Zed has suggested, it sounds like the overrun clutch in the starter is bad. How does the auto part store test the overrun clutch? I suggest they can't.

Check the mechanical advance separately (remove vacuum hose) and then check the vacuum advance separately at idle by connecting the vacuum servo to a vacuum pump (Mighty-Vac) or manifold vacuum. Add the 2 together for the total. There are advance curves for each in the factory service manuals. If everything is working properly they will compare favorably to the factory data.

Hmm...your photo shows a 3-wire connector for the tach. The early 240Z used a 4-wire tach that used a current pick-up on the positive side of the coil, like the photo on HybridZ in the tach thread you are posting in. If your tach is a 3-wire tach that would explain the extra black wire on the point side of the coil. Why the tach does not work is still uncertain though. Are you sure the tach is getting power, ground, and the signal from the points?

I assume you mean the photos in post #14. Your wiring does look like there is a mistake. The black wire going from the coil - to the points (in the distributor) should not have any connections to the wire loom. The splice from the green/white to the black/white looks factory. Where did the green/white wire go in the last pic? The green/white is the starter bypass wire and should connect to the coil + or the coil side of the ballast. You need to identify the 2 black/white wires. One comes for the ignition switch and will have +12 volts with the key is on. This wire connects to the ballast. The other black/white wires comes from the tach and goes to the coil +. The green/white wire is the starter bypass and only has +12 volts when the the ignition key is in the START position. This wire also runs to the tach and completes the loop up to the tach (the return is the second black/white wire). If you reverse the 2 black/white wires the car will run but the tach won't work and the ballas is out of curcuit so the coil will overheat after a while.

Yup. Nice Z.

The blue wire is the constant power to the clock. It comes from a red/blue wire that feeds several of the other accessories that work when the key is off.

No, the aftermarket tach will work with the stock ignition system. The only modification to the igniton system will be to replace the current pick-up loop with a piece of wire to complete the primary circuit.

I can hear the noise you mention. Just to hazard a guess: Based on your description and the noise in the video it could be a problem in the ECU that is allowing an oscillator or clock signal out to the injectors and the injector coils are ringing in response to the signal. If you have the capability connect an oscilloscope to the injector wiring and look at the waveform. I know this might seem wierd and unlikely but it came to mind. FWIW.

The instrument lights get power from the dimmer rheostat via a red/blue wire. The rheostat is powered from the parking light circuit via a green/white wire.

You want to buy a tach that uses a voltage pick-up. This will have a wire that connects to the negative terminal of the coil. Most aftermarket tachs are this type. Considering that no new cars have points anymore some aftermarket tachs might not work with a points type ignition system so make sure to choose a tach that very clearly is designed to work with a points type ignition system.

3ryce, it would help if you were to provide additional info about your car. What type of ignition are you using? Points? Pertronix? Electronic module from a newer Z? Other? Anyhow, from what I can determine your car is running fine and primary goal is to get a functioning tach. So go buy an aftermarket tach already. That is your easiest and cheapest solution. As for the use of the adapter with or without the MSD ignition system, ask MSD, it's there product.

Another option: The adjustment plate has a vernier with degree marks on it. Simply note the position prior to removal. As long as you don't loosen the "hidden" adjustment it will be easy to get it set-up in the same position using the vernier. Keep in mind that you should check the timing after servicing the points. If you do not have a timing light set the timing with a buzz box or a test light.

The fuel pressure will drop after shut-down due to bleed off thorugh the return line. The increase after a few minutes could be due to heat soak heating the fuel to the boiling point and causing it to turn to gas. You seem to have made a vapor lock indicator.

Bypassing the ballast will only help if the problem is with the START position. From what I get our of comments you get one spark when you turn the key on and another when you turn the key off. This suggests you are getting power to the coil and Pertronix. Perhaps the Pertronix is bad or there is a problem with the magnetic piece you placed over the points cam. Yes, you can use a piece of speaker wire directly from the battery positive to the coil and Pertronix. That is what I would do to eliminate the primary wiring from the equation. The result will provide direction on where to focus your efforts.

Make sure the throttle linkage is adjusted properly. If one of the rods is a bit short it will hold the throttle open. The carbs should both be able to close fully with the throttle stop screws backed out all the way.

The voltage at the coil should rise to the battery voltage when the key is in the start position. If it does not the ingition switch might be bad. The ignition switch is suppose to bypass the ballast while cranking. Have you tried connecting the coil and Pertronix directly to the battery, bypassing the iginiton switch and wiring? Perhaps it will start that way.