Zed Head

I think that thing in the valve cover hose (edit - left out the "hose" earlier) is called a flame arrestor. It is kind of odd how Nissan decided to put that port on the very top of the valve cover. Seems like they could have shot it out the side and saved an inch or two of engine height. I wonder if the valve cover is designed to distribute the fresh air over the rocker arms, purging the area evenly, leaving no dead zones for sludge buildup. You could get fancy inside the cover and seal up the air supply area, creating a type of manifold, then place the fresh air inlet at the back or front of the cover to feed the new manifold. Run the air supply hose next to the fuel rail, or underneath the intake, to streamline things. Edit 2 - looking at JSM's picture I realize that the filler cap is also high. So the PCV elbow height isn't that significant.

Manifold vacuum has little to do with determining if you have a vacuum leak. What it measures is how well, and how, the engine is pulling air. You might have a vacuum leak but that's not what the vacuum gauge is used for. And you'd be better off to block the brake booster line and use a small port on the manifold for the gauge. Plus, when you give a vacuum gauge reading you should also include RPM. Might be worthwhile to reset and re-describe what the problem is. You've probably changed some things, and verified others, and have more numbers to report, since the last post almost three weeks ago. And you might be better at describing what's going on. We're on Page 2 now and I don't remember what the issue is beside rough-running. It almost always helps to review work done.

Maybe not magical, but practical? That large chunk of mesh at the PCV hose port in the block acts as an oil most separator, I think. We used to build them from pipe and steel wool to separate oil on vacuum pump exhausts. If we didn't have them they'd spray a substantial quantity of misted pump oil. You could add mesh at the valve cover entrance/exit probably. Or do a catch can. Seems like both top and bottom see the same thing, exhaust gases from blowby, either rings or valve seals, and oil mist from moving parts.

Looks like it's priced for the turbo. Front end looks bad, bumpers gone, only showing one door panel and one seat (makes you wonder). No idea where you're looking or where you are, or where the car is, so advice will be limited, re rust. I got a complete 1976 car with minimal rust, non-running, for $1000. Got 20,000 miles out of the engine once I got it going. If you're just looking for a sound body, there might be better options out there. Also notice that that's a 280Z fuel rail, not a 280ZX fuel rail. Could be that all it really has is a TURBO valve cover. Beware.

You could swap n a 1980+ 280ZX engine with a P79 head and CHTS. Run the wire around the back of the cylinder head. Or you could pair an AD and DA converter, with wireless technology.

Does it close? That's the important part because it's the only thing that makes it different from the idle speed air bypass screw, which also does what CO described for the AAR. You should be able to raise your idle speed by turning the idle speed screw. But it will stay high after the engine warms up. The AAR doesn't stay open very long, it has its own internal heater that closes it well before the engine gets to operating temperature. If you connect a battery to the terminals you can watch it close if it's working correctly. Some people remove them and just hold the throttle open for a short while. As Captain impled, it has very little affect on how the engine runs. It's just a convenience.

You haven't said if it was full of coolant. And hose pressure is really only a test of the radiator cap. Pressure comes from heat and expansion, and the pressure is distributed evenly through the whole system. Didn't say either if you drove 10 minutes on the highway or ten minutes through the traffic lights. Just making the point that it's the little details that will tell the story. If you've been hitting 240 and you had a steaming engine, you might have a blown head gasket. You might never know if it happened before or after the belt change. But it might be the cause.

If you're sure that you're measuring resistance through the pickup coil itself then that $30 Autozone coil is the way to go. They don't fail often but they do fail. Didn't even know that you could get those at Autozone. http://www.autozone.com/ignition-tune-up-and-routine-maintenance/pick-up-coil/duralast-pick-up-coil/80242_0_0

The overheating could be coincidental to the belt swap. No cause and effect. Belt and fan problems would show up at idle, like at stop lights, or slow driving. Radiator problems show up at highway speed. Thermostats affect both. The "haha I only saw steam" comment sounds like you don't have any coolant in the system. You didn't' really explain what you meant. Are you saying that the radiator is not full? That could be the whole problem right there.

It does look that way. From here he could go through the 1978 Engine Electrical chapter tests. Your documents might be a bit much for the OP at this point in time. Just saying, it took a few days to get to the pickup coil. No offense. To the OP - the rotor pulls right off the top of the shaft, in that picture, it's a press-fit. That will give you a good look at the other parts. The wires to the pickup coil look fairly weathered, they could be broken where they enter. Also, there are other things you should check while you're n there, but it might be best to focus on one at a time.

Darn it. Just realized I was looking at your terminal block wrong. It's actually right for 78. Ignore all comments about two pickup coils, yours looks right, a block for a single pickup. But the resistance you measured isn't right, it's way too high, essentially open Triple check those wire ends, it looks like somebody put new ends on, and might not have got them right.

Looks like you have a mish-mash parts. A single pickup distributor, which is right for 78, but a two pickup terminal block. If I read your meter right, you're in the Mega-ohm range. Not the spec. you're looking for. The test shown in the FSM, for that distributor, is from the TIU plug but it ends up on the same wires you're testing. Spend some time making sure you're getting good contact with your probes and that the ring connectors haven't broken loose from the wire ends. The test and spec. is shown on page EE-32.

If you have a 280Z igniton system you want one of these manuals - http://www.classiczcars.com/files/category/13-280z/

We might all be getting distracted. Maybe you should check for spark. Could be a fuel supply issue. An easy test is to squirt starting fluid in to an intake manifold port then try to start it. If it starts for a second, you've been on the wrong track.

That would be good to know but it won't tell anything about the ignition system. There are a green and red wire coming from the direction of the distributor to the terminal block, in his picture. So odds are decent that it actually is a 280Z type system. But, there's no confirmation. Beside seeing the trigger system, if he removes the cap, it will be easier to explain about the air gap and the pickup coils. Notice also how dirty the terminal block and wires are. Could be a simple shorting out of the trigger pulse. What's kind of funny is that back in the days of points, removing the cap would probably be the very first thing a person would do if they had a spark problem.

The intake manifold and parts look like an 80-83 280ZX engine. I was serious when I said to remove the distributor cap, take a picture, and post it. Half of the ignition system questions will answered.

Other oddness - his picture shows the terminal block and wires for a dual pickup. But 78 supposedly doesn't have that option. And the module that EuroDat showed is for a single pickup, with a 78 plug connection instead of the earlier screw-terminal type. I've used a single pickup 78 module in my 76 dual pickup car though, so that swap is doable. Proposed next action - remove distributor cap and take pictures. Many questions will be answered. Edit - there seems to be an extra ground wire (although it looks red) on that terminal block also. Maybe a clue?

You haven't really described the "noise", beyond noise. Just saying...

The mustache bar bushings are known for transmitting gear noise from the diff in to the body and cabin. Usually noticed on the highway when cruising along. Or they're noted for being loose and letting the diff move when shifting, causing a thump. Not really known for bump noises. You might be looking at the wrong area.

Is it sure that the distributor is the 280Z unit? I can't tell from just looking at the cap in the picture, but the idle speed screw is ZX style so it looks like somebody stuck a complete engine in. Could be a ZX distributor. And they have their own set of problems, with loose bushings, broken reluctor magnet rings, and modules that experience sudden death. Which it is changes the thought processes. Would be worthwhile to take a close look at it. Look for the "black box" on the side of the unit. Here's a picture from atl Z. And a link showing the problems and parts. http://atlanticz.ca/zclub/techtips/distributorrebuild/index.html

These engines are prone to detonation and detonation is a very powerful force in the combustion chamber that can cause damage. When you advanced the timing you made detonation more likely. Or, it's just got miles on it and it finally let go when you were hooning around enjoying the extra punch. Pretty cool though, how these guys narrowed it down to the exact cylinder and details of what you would see, huh? Wizards. Now you can start a new thread soon, titled "how do I remove this broken bolt/stud fragment from my head/block/whatever". It will be fun.

Nice detective work. I've heard of the pickup coils dying and actually have a bad one in the garage. That's a simple meter test. He could also trigger a spark through the coil discharge wire, and watch it with his timing light, by grounding the negative post quickly (tapping to ground with a lead wire) with the key on. Make and break. At least he'd know that the coil can produce a spark and the path to the discharge wire is intact. Just need to get through the basics before suggesting a ZX distributor or HEI module.

There are several tests you can run described in the FSM. Not sure what "book" you're referring to, but it seems like the wrong one, considering the next-to-the-battery module location. You didn't say what year 280Z either. Use the Factory book from the Downloads area. You have power to the coil. It's not likely a loose wire on the input side. It's probably the module itself or the pickup coil in the distributor. Do the simple meter tests shown in the Engine Electrical chapter.

If it's coolant then it would be a head gasket, probably. There are other possibilities. Hope for a blown head gasket.

Don't get crazy swapping parts. You're a little off on how the system works. There's not supposed to be voltage from the coil to the cap until spark happens. Then it's one giant blast of voltage that would blow up your meter if you tried to measure it. The fact that you have power to the coil implies that it's a module or triggering problem. The pickup coil inside the distributor does the triggering.