Zed Head

This guy from Atlanta posted on the Portland Craigslist. 1978 Datsun 280z, 28,534 miles

Without a machine you either have to do some detective work on the parts and part numbers, or test advance while it's on the engine, with a timing light. The weights for the centrifugal advance have numbers stamped on them which indicate full advance level. But the springs determine rate of advance. The vacuum can is hard to to identify. The parts place distributors have mild curves I believe, so that no engine damage will occur from too much advance. but if you get a factory distributor from about an 81-83 distributor you might get some pretty high advance numbers. It's one of those dilemmas. One small advantage of the HEI module swap, in that you keep your stock curves. Some of the members have recently installed programmable electronic distributors from a new supplier, 123ignition. You're in that zone of time, money, and complexity decisions.

That would be the stronger Borg Warner T-5 transmission, FS5R90A. You can see it in the FSM, MT chapter. It's not a direct swap in to a 240Z, like the Nissan 5 speed is. It will need some transmission mount work and a shortened driveshaft, I believe.

Thanks for all the feedback. I went with Windows 7 Home Premium (Amzon ~$99), a newer version of Microsoft Office (Craigslist from a local IT guy who gets paid in software occasionally, $40) and ~$21 worth of newer faster memory from an Amazon source (2GB total). Windows 7 is about like an improved version of XP if you turn off the Aero stuff. The increased, faster memory made a big difference. Good for another 5 1/2 years, for about $160. Barring old component failure (my CPU cooling fan is attached with a long zip tie).

I think that sscanf is right, the technology of the system was improved by 1979. The ballast resistor is gone, for example, so more current through the coil for a better spark. Plus, the cost of just the old technology module is more than the newer module and distributor combined. Same topic though - you could keep your old distributor and wire in a GM HEI module and GM HEI coil for less money (~$25 total) than either for probably equivalent technology. But if you need a distributor, you might as well go with the ZX system. The ZX way is easier to wire in also. Don't forget to check the advance curves on a new distributor.

It worked for me on a bigger leak at the back of the head. Mine actually dripped down the back of the engine while warming up. If you just have seepage, the odds are good. Bar's seems to be the popular one.

Just to be clear, you might need to seal the bottom tube also, to be sure. There are two passages in the manifold itself, the valve on top controls the flow between them. The plate will seal the passage but if the wall between has holes, it won't matter. You'll see how it works when you take the valve off the top. Look inside and you might see some damage. Just an improbable possibility.

Hook everything back up, remove a vacuum line from the top of the intake manifold and squirt some in that way. The easiest is the tiny one that supplies the heater valve control bottle. That way you'll have fluid in the intake manifold plenum so any air passing by will have to pick some up. Be aware also, that all openings to the engine have to be sealed. Oil filler cap, dip stick tube, all vacuum hoses, valve cover bolted down, etc. The intake system is connected to the PCV system so any leaks in to the engine will be a leak in to the air intake.

How did the spark look? Blue or orange and weak? And when you say starter fluid do you actually mean starter fluid or something similar like WD-40 or brake cleaner (people do things...)? Read the Engine Fuel chapter in the FSM. Those overgrown o-rings and other stuff will make more sense. It should run with starter fluid if you have spark and nothing major went wrong. How did the plug that you pulled look? You might have just re-fouled it with bad gas when you re-installed it.

Size comparison. Edit - Normalized in the post, resized to original when clicked. Handy.

I think that he wants to go directly to electronic with the least amount of fuss. The MSD option would be great if the tachometer problem didn't exist. No load on the points to wear them out, reliable points trigger with a reliable electronic ignition. Pertronix modules have their own issues, like burning out if you leave the key on. If he switches to an electronic distributor then he has to get in to advance curves. It's surprising that MSD doesn't put a little effort in to clearing up the tach issue. I'd guess though, that people that developed the product are long gone and those that are thee now just repeat what the instructions say. What's wrong with your tach operation that you need to develop a circuit board?

The reading on the vacuum gauge tells about the state of the various engine components - valve timing, valve condition, ignition timing, valve seals, rings, power balance between cylinders, etc. If the engine is running, it doesn't tell you anything about vacuum leaks in to the manifold. With a vacuum leak, the engine RPM can increase, actually increasing the intake vacuum or keeping it the same.

To siteunseen's point on the EGR- there have been cases where the internal passages of the EGR have rotted out. If the tube at the intake manifold from the exhaust manifold is open, and the EGR passage in the manifold is rotten, it would be a vacuum leak, even if the vacuum nipple is blocked or even if the top of the EGR has a plate sealing it. In the same vein but a bigger stretch, the internal-hex head nuts in to the EGR passage could be loose. Very unlikely though since they're really hard to loosen.

I saw the word "booster" earlier in the thread and assumed it had been covered, but does the problem happen when your foot is on the brake pedal? A bad booster diaphragm will cause a vacuum leak. Foot-on-brake might be coincidental with high RPM.

Throttle blade hanging due to PCV gunk was an issue documented by Nissan. Addressed with a factory published remedy in a Nissan Technical Bulletin. Just to more clearly restate what I posted before. Easy to test. Stick toe under throttle pedal and pull up when RPM are hanging high. Takes a little finesse but you can actually get skilled at it while diagnosing. If RPM drop the problem is between your toe and the throttle blade/throttle bore interface.

Do you still have the throttle linkage dash-pot? They get worn and sticky. The throttle blades get sticky in the bore also due to PCV backwash. Carb cleaner around the blade will clean it up.

It seems like the tests show that the injectors are okay but the connections aren't. There are two sides to the connection - power supply, and grounding at the ECU. You can check the connector pins with a voltmeter. We just had a big discussion about in another thread. You really need to switch from a phone to a computer to get the good direction on what to do. It's all in the Engine Fuel chapter of the FSM. http://www.classiczcars.com/forums/fuel-injection-s30/52066-no-start-fuel-injectors-not-firing-1978-280z.html Datsun Service Manuals - NICOclub

What were the results of your tests? And where is ZUPPAN?

What year was it? The early S30's (up to mid-74) are known to be more flexible than later.

Beware that outside of the relay may not represent the condition of the inside. They're easy to take apart, just bend the little metal tabs.

What is the idle speed before it starts to stall?

You should consider your skills, relative to what the car needs. Everyone has their own specialties and areas that they like to work in. Some people do body work, some paint, motor-heads, electrical, etc. Do you know much about small block chevys? Cold start behavior is way down the list of things to worry about. It's a 77 so you might need to pass emissions standards. Find out what's allowed in your area. Make sure the title is clear and correct. Since summer in your state is only about 3 weeks, you should have lots of time to fix any problems. Make sure the problems are ones you'll enjoy working on.

beerman, since you know the Mastech, can't he just get the probes where he wants to measure and turn the knob until he gets an in-range reading? Then re-zero, if he needs to. I've been spoiled by my auto-ranging meter which also reads negative. But I bought it because my old Micronta meter wouldn't calibrate to zero anymore.

I don't think that you want a coil with a ballast resistor. With the MSD you can use one of their high performance coils, with no ballast. The points are only used to trigger the MSD so the ballast isn't needed anymore, if you get a better coil. Many people have problems with getting the tach to work. I looked at the instructions though and see something I haven't seen before that might explain why some get it to work and some don't. Copied it below, from Page 7 of the 6201 PDF file. I think that the original ballast should work, I don't know why you'd need the Chrysler dual ballast. If I understand what they're trying to say, that reducing current through the points will keep the tach working. As I read the instructions I realized that they're not very well-written, and give poor explanations of why the wires are connected where they are. Good luck. BALLAST RESISTOR If you have a current trigger tach (originally coil positive) and use the White wire of the MSD, you can purchase a Chrysler Dual Ballast Resistor (used from 1973 - 1976) and wire it as shown in Figure 5.

Not sure that you understand what resistance is. When you disconnect the gauges you wouldn't get rid of resistance, you would create infinite resistance (ignoring the conductivity of air). "No resistance" would be a very very small number or a zero on your meter. High resistance, or "some" resistance would be a number from typically 60 to 1,000's of ohms for most of the tings you'll measure on your car. Infinite resistance would be what you get with the meter probes touching nothing at all, just air. You really need a meter that you understand to get good measurements. The cheaper, or older, meters have an adjustment knob on the face. After you pick the range, you touch the probes together and move the knob until it shows zero. Then you know what "no resistance" looks like. If you have a small light bulb, like a dash bulb, handy you can take a measurement on it to see what "some" resistance looks like on your meter, with one probe on the center electrode on the bottom and the other probe on the shiny metal side of the bulb. A typical bulb will measure about 4 ohms. You need to get good resistance numbers, and know what the proper range of resistance is for what you're measuring. Some resistance is good, it's how things work.