Zed Head

Do you have a picture of the exploded coil? I've never seen one or heard of it happening. An internal short could pass enough current through to heat it up rapidly but even then the negative terminal wire and positive terminal wire would have to pass the current, and the negative terminal would have to supply a ground path. If the ignition module was shorted or the negative post wire shorted to ground, the coil could heat up more slowly and maybe get hot enough to smoke or something. Either way, the coil itself would only be the cause of the "explosion" if it was internally shorted, and there was a path to ground on the negative post side.. More likely that the source of the failure is somewhere else. Better check the other components before you get carried away with new parts. Heat comes from current and current only happens when the circuit to and from the battery is complete.

Sorry for stirring things up folks. I got carried away with what seemed funny about the first post. "Spend $14,000...you're welcome." Funny.

What year Z and is the ignition system the factory stock parts or has it been modified? Primary resistance is your main concern. Welcome. Most people don't get exploding parts to help them diagnose a problem.

Edited/ The video was pretty funny, I thought, but doesn't help anything.

Edit - I should not have replied to the post. Should have let it fade away. Sorry. (Removed some stuff here). I only posted the graphic to show the physical distance. I did a Google on the name and zip code (weird that zip codes are global).

Edit - I wrote the below while you posted. Another simple check of just the lines and system up to the calipers would be to disconnect both calipers and place the ends of the lines in two containers. Sit in the drivers seat and pump the pedal a few times (don't bang the MC piston off the end of the bore, use short strokes). If the lines are open and pressure is fairly balanced you should get about equal volumes in each container. If you don't then you can just go backward toward the MC. Disconnect at the switch and make some stubby lines to check flow there (you have a number of old pieces laying around by now). Do the same test. Since there's only a single line for the fronts to the switch there's no reason to go above the switch. There's no left-right up there. That will break the system up in to three parts - the calipers, the lines, and the switch.

Don't they use the same calendar in Neuvecelle as the rest of the world? This thread is 13 years old. mikewags hasn't visited the site since 2010. Welcome to the forum.

Maybe this will help, below. I see flow and pressure and force being used all in the same train of thought. Flow is what starts things happening, but once flow stops you're left with pressure. And pressure is what creates the force on the rotor that stops rotation, via friction from the pad on the face of the piston. If you know that you have flow when you press the brake pedal, when the brake pedal stops moving you can stop thinking about flow and focus on pressure. Once flow stops you have to have equal pressure throughout the system. It's a law. https://en.wikipedia.org/wiki/Pascal's_law

I'm not saying that blocking the holes is your problem. I'm just focused on your testing methods. You haven't isolated the source of the problem to a smaller area. Everything after, and including, the switch is still in play.

I'm just saying try the same things on both sides. You have one side that works and one side that doesn't. See if you can blow air through the inlet to the bleed screw on the right like you tried to do on the left. And yes, I am saying that the piston might be able to press far enough in to block the holes. The calipers are designed for a known thickness of pad and rotor. So, whatever works on the right, match it exactly on the left. And, vice-versa.

You didn't describe the same action on the right side. Since you have a symmetric system you're in a good place to compare one side to the other. Might be that the piston will retract in to the bore far enough to block passage from the inlet to the bleed screw. With two sides that should be equal you can compare identical actions until you find the one that's different.

Hydraulic principles say that if the system is connected correctly that you will get equal pressure on left and right. It's not possible to have one side pressurized and the other not. So, air leaks are not an option if the right side works correctly. If you are getting fluid from both sides by pressing the pedal then what might be happening is that the piston is bound up in the caliper. There's pressure but no movement. Assuming that the hydraulic lines are correctly installed. Or, there's a blockage inside the switch. You might disconnect both lines at the switch and see if you get good flow from each port. I sure hope that I don't start seeing a bunch of pharma ads about flow or stream... p.s. I wrote this while others were posting. But, "first principles" apply here, as far as problem solving. The end of the warning switch has an inlet and two outlets, and hydraulics apply. The only other variable might be time, but if somebody is sitting in the driver's seat with their foot on the pedal the fluid pressure will equilibrate.

Blow some air through them.

Left and right use the same chamber in the warning switch. The pressure should equalize between left and right. Hydraulics.

With the newer slave cylinder that is what is supposed to happen. The internal spring pushes the slave piston forward, taking up the play. Self-adjustment. Can you push the rod back in to the slave cylinder with everything connected and ready to use? If you can't then you might have a problem.

Check the seat in the switch itself. A bright light and a good look will usually show you the seating/sealing surfaces and if you're getting full contact around the circumference. Looks like you found your air leak though. Air has much lower viscosity than fluid (of course), you can suck a lot of air in where just a few drops of fluid come out.

Your problem sounds a lot like mine when I had the bleed screws on the bottom. But yours are on top. What method are you using for bleeding? The MC's can leak internally, the seal for the fronts can blow and the fluid just washes back and forth over the seal as the piston moves. And quality of aftermarket parts is poor, in general. Parts from the same manufacturer might have had the same unskilled person building many MCs in a row, repeating the same error. If you decide to try another MC try a different brand. I'm going to bet on bleed technique though.

Does the pedal go to the floor or does it stay high and firm? If it goes to the floor can it be pumped up? The pistons don't move far at all under normal operation Are you saying the the wheels still turn with the pedal down? Not really clear...

Red on(in?) white 72. A "survivor" by my standards. Looks pretty good. Very little salt used over here and when it is it gets washed away by gallons of roadspray pretty quickly. https://bringatrailer.com/listing/1972-datsun-240z-205/

You might squirt some oil in the cylinders too. Your low pressure numbers might be because the pistons aren't drawing in the air. Could also be that your carbs aren't working right. You don't know that the float bowls are full. Starting fluid answers a lot of questions. Big time saver.

Use something more flammable. Starting fluid, carb cleaner, hydrocarbon brake cleaner. Or gasoline. And make sure it gets past the pistons in the carbs in to the runners.

What fluid did you use?

The compression number range is not terrible. 12.5% on #4, the worst one (actually 15% - 25/165). The equipment used will affect the readings. And the lash readings do show lash so the valves should be closing. Maybe the engine spins fast because you have a powerful battery. You have reasonable cylinder pressures and the engine is spinning. The engine should start. So, spark is left as the unknown. With the engine spinning that fast you should be able to get a nice stable ignition timing reading with a timing light. If you can do that, it will tell a lot. And, there are no pictures of your spark plug wiring. Might be that they are incorrect. 1 5 3 6 2 4 counterclockwise. Spark and ignition timing seem like the main unknowns at this point. They have not been confirmed.

That is the opposite of how it's done. First or second thing I would do is remove the valve cover, take a.006" or thinner feeler, find a lobe that has the point pointing up, and see if you can slip the gauge between the round part of the cam shaft (no lobe or ramp) and the rocker arm. Do that on all of the lobes that are one the base circle. Won't be a surprise if you can't get the gauge in. Or, get a cylinder pressure gauge ( I think that you can borrow them from a local auto store) and measure cylinder pressure. It's easy to do. If you get low numbers, then you can get under the valve cover. If lash is correct it might be that you have bent valves. There is an odd noise about every rotation in your video. Doesn't sound good.

Sakura Garage is @cgsheen1 and his son, I believe. No surprise that they figured things out. Might be that the problem was an opening and closing issue. The flow test was probably just wide open. The rig for pulsed testing is kind of spendy and more complex. I wonder if the "bad" injectors were original or aftermarket.