Zed Head

Is that with the wire connected or disconnected? Sorry, but these things make a difference. What you might be seeing is voltage from a pullup resistor in the module, that goes away when the other side of the transistor gets power (full disclosure - I don't really know about this). Transistors and the way they're used is not typical electrical stuff. I'm just trying to get you to something that makes sense. It shouldn't be that hard. If you're tired of my comments, I can bow out. I asked about the positive terminal on the coil because it should be connected to the blue wire you measured, through the coil. Module-blue wire-ballast-short blue wire-coil negative-coil windings-coil positive. If you don't see the same thing at the positive terminal it will give you a clue about where the break in the circuit is.

It's not clear where you're measuring. Blue wire at the module, at the coil, at the ballast, or the mystery blue wire? Does anything else that should have power not have it when the key is On? Like the positive post of the coil?

Did a piece of the head casting break off or did the liner just work its way out if its slots? A closeup of the damage would be interesting. Your problem is the reason that some people recommend avoiding the N47 or P79 for use with turbos.

Good point and clarification. I made an assumption from a collection of french model statements, off the internet. The HEI module only has G and W as pin ID's anyway, with W identified for "positive" from the distributor in the various writeups, but G and W are just GM wire color letters (green and white). I think that people just used positive because the correct wire from the Nissan distributor is red. In retro, when I first got in to the HEI game, I remember wondering what "positive" really meant since each wire sees both positive and negative current. "Direction" is different but I don't know what the proper name for that is. Even rising and falling don't mean much. The ZX trace will be really interesting. You might start a run on ZX distributors if a performance benefit is found. There's definitely a rumor floating around out there but no data.

Apparently you can remove the liners. Some do, for the general bigger-is-better concept. But the remaining hole is probably not good for flow over the normal RPM range. It has no shape. Somebody did some flow-testing on a variety of heads and found that the liners didn't hinder flow, on a stock N47 head. I would be concerned about an imbalance between cylinders. May not be a real issue. I've never heard of anyone using a head after they discovered a liner fell out. Pretty sure that they're cast-in. Maybe someone could weld the broken aluminum piece back in, if that's why it fell out.

This is probably the key statement. I bought my car because it was straight, non-dented and mechanically sound. But it didn't run. Because I was looking for a garage project and like the mechanical, electrical, mostly engine-based things. Hate bodywork. I was actually thinking about a small-block chevy swap and only got the engine running for in-the-meantime. If you buy a car that's too complete, there won't be anything to do to it.

It is just a theory. Nissan may have become aware, but they didn't fix it. Pathfinder VG30E's have a similar problem. Broken studs, snapping at the head surface. Mine sounds like crap, I wish I lived by a Nissan executive's house so he could hear it every day. They're a pain to work on.

Pretty cool. I think that might be backward since the 4 pin module triggers "going positive" (according to the Megamanual - link below). You can see how timing gets all screwed up if the wires are backward. The zero-crossing is pretty broad. You don't have a ZX distributor do you? It has a different-shaped rotor. I've read some things that imply the ZX distributor has better high RPM dwell. I wonder if the ZX rotor shape gets the signal above positive quicker so that it can start charging the coil again. I'm assuming that the trace has to be in a certain region for charging to start. Could be wrong. General Motors 7-pin HEI Ignition Control

The dimmer switch is actually at the base of the turn signal stalk. The parts that you're showing in your picture are the switch assembly (two switches on one board) that supplies power to the headlight circuit and the running light circuit. Notice in SteveJ's first FSM copy picture that someone wrote in "ground". RB and RW are grounded there, one or the other by the switch at the base of the turn signal stalk. I've fixed a problem like yours by spraying contact cleaner in to the base of the signal stalk and working the dimmer lever. It gets gummed up if it's not used regularly.

I was just wondering what your reason was. I have a bowed exhaust manifold that I bolted on to a head and found that it doesn't take much force at all to bend the manifold down to the mating surface. Probably a millimeter gap closed up. The surfaces may not be parallel but the tension applied by the ends of the manifold are not much different than in the middle. Not extreme, for sure. But that's the advantage of having a collection of parts. Even the defective ones are useful. My theory is that the three bolts in the middle of the exhaust manifold hold it tight to the head and that the ends of the aluminum head expand away from center farther than the steel manifold. Aluminum has a higher coefficient of thermal expansion than steel. In other words, if they start out in the same spot cold, the aluminum will grow more than the steel when hot. The hot-cold cycles bend the stud back and forth farther on the ends. That's my thinking anyway. Really, the 10.9 grade might have similar fatigue strength to a grade 7 or grade 8. It's a property that's not considered much. How do you know the Nissan studs are grade 7? I'm no bolt-stud expert, but that's an odd number. 2, 5, and 8 seem to be the common ones, American. 10.9 is a metric standard. And seems to be identical to Grade 8, property-wise. So we've probably been talking in circles.. http://www.tessco.com/yts/customerservice/techsupport/whitepapers/pdf/bolt_grade.pdf That's the beauty of the forums - you have to go learn some new stuff just to keep up. Here's an interesting book on fasteners that I browse through when things start to fade. Carroll Smith's Nuts, Bolts, Fasteners and Plumbing Handbook (Motorbooks Workshop): Carroll Smith: 9780879384067: Amazon.com: Books Might be cheaper here but it looks like his web site is screwed up. It's missing. www.CarrollSmith.com -- Purchasing

I see that you're using a "straight-shot" modified fuel rail. It's possible that you might have fuel pressure pulsing issues, or pressure degradation at the last few injectors. I think that's why Nissan fed the injectors from both sides and installed a damper in the back. I've read that the large volume of more modern rails helps counteract those problems. It will be interesting to see if you have heat soak problems with the smaller rail volume, but with headers. Hope you don't but the set of parts is interesting since nobody has that combination. p.s. I assume that you found one more injector to go with the eBay set?

It's not a tension problem. The threads would probably pull out of the head before the stud failed from tension. But it sounds like you've made up your mind. Probably not a big deal either way. Why are you following Nissan on the nuts, but not on their stud grade? Don't you want to use lock washers and threadlocking compound? Just curious about the logic path.

You can get Nissan factory-quality manifold studs from the dealer. Designed for the application. High numbers in a bolt or stud grade doesn't mean that they're better. Just that they're different. You don't need super-high yield or ultimate tensile strength, you need fatigue and heat resistance. Constant bending and heat-cycling is what breaks the studs. Better to get a stud that's been tested for the application by the factory. You can get the part numbers here, and your dealer will have them. If you get a good parts guy he can find them on his own by car model. They're common and cheap. Datsun 280Z Cylinder Head, Rocker Cover & Thermostat L28E You can get the nuts also. Notice that there are no lock washers. Datsun 280Z Manifold, Egr. L28E (From Aug.-'76)

You might measure combustion chamber volume to see what your CR will be. You might find the flat-top L28 puts you at 12:1 or something.

Continuity is used to check if two points are connected. It does not tell you if there is power. The distributor and ignition module are involved in the injectors' opening and closing. The ECU is connected to the coil via a blue wire to the negative terminal of the coil. This wire also connects to the ignition module. The ECU opens the injectors every three sparks. The ECU also needs to have the tachometer connected to work correctly. I believe that it may be part of a pull-up resistor circuit, but that doesn't really matter. Make sure that the blue wire from the coil negative has continuity to Pin #1 of the ECU at the connector, and that it is connected to the ignition module, and that the tachometer is connected properly. The fact that the engine ran for a little while implies that you have power to the fuel pump. You can check that by removing the small wire from the starter solenoid and turning the key to Start. The engine won't turn over but the fuel pump should run.

You're right, there is a lot of stuff out there, and it's hard to tell what's right and what's wrong. I gave up and just installed the GM HEI external coil to match the module. I think it ohms out at 0.7. I figured I couldn't go wrong with the original GM specs., used on cars like the Camaro with a V8. You know those will see some high RPM. I think that the Pertronix HEI module (there are other brands also like Accel) just has a higher current limit. With a low ohm coil, the heat dissipation is probably the key ot making it last. The new module in the old box in the cabin is certainly cooler than sitting in the engine bay or under a GM distributor cap though. Shouldn't be a problem, I'd think. Plus you can reach over and touch it while driving, and turn on the AC to keep it safe. Here are some of the other brands. Still popular. http://www.summitracing.com/search/department/ignitions-electrical/part-type/ignition-modules/distributor-type/hei

I don't think that the BIP373 has "dwell" control, or the current-limiting function that the HEI module does (and the 280Z and ZX modules). That is one of the things that makes the GM HEI module so useful, it won't allow the system to overheat from too much current. The BIP373 is used with ECU dwell control, I believe, and would probably burn up itself if used. If it triggered from the VR distributor. Not really sure that it would work. Are you using one? How does it control dwell? I think that you could use the BIP373 in place of the ignitor on the 280ZX ignition systems though. People use the HEI module to replace the ignitor, but the BIP3737 seems like it would do the job, for cheaper and in a smaller package. Might have problems with the engine heat though if it was installed in the same spot. Here's something interesting on the GM HEI modules - it looks like Bosch licensed the technology from GM or vice-versa for a few years and several of the outside-the-US manufacturers used the design, in different form factors. The very last one on this page looks like it is the same as the 4-pin HEI module but the pins seem more convenient. I think I've seen the same on a BMW model out there somewhere. Bosch Ignition Modules Edit - BUT, I just found it on Rockauto and it costs $204. So the more compact form comes with a cost.

If you read a few more threads on "running rich" you'll see it recommended often, to measure resistance of the coolant sensor circuit at the ECU. There are several connections along the way that can add resistance. What the ECU sees is what matters. Download the Electronic Fuel Injection Guide from the first link below. Get a meter, even a simple one will do. Try to find a way to measure fuel pressure. Read the Engine Fuel chapter, especially the first few page, if you want to understand how all of the parts work together. You'll waste a lot of money if you just guess and replace parts. XenonS130 - S130 Reference Amazon.com: multimeter XenonS30 Index of /FSM/280z

I looked for maintenance information on the wheel bearings but couldn't find it. But now I see that it's also in the Owner's Manual. Since becoming an FSM advocate I almost never look in there anymore. Thanks for the tip. By 1976, maybe earlier, they were down to 25,000 mile intervals. As your link points out though, one cause of failure is contamination during repacking. It's a dilemma. Probably worthwhile to get one of those grease packing device to reduce handling if you're going to do it.

The non-turbo transmission does not require a new driveshaft. The turbo transmission does. The turbo transmission has a very different shifting mechanism. The non-turbo will look almost identical to what you have now. That's one way to tell, if you're already sure that it's an 83 280ZX transmission. The extra switch wires can just be left disconnected.

The front bearings are tapered roller bearings, the rears are ball bearings. May not matter. Seems like the automakers would have installed a Zerk fitting if it needed it. I don't think that re-packing the front bearings is even a maintenance item either. I remember re-packing the front bearings on my 78 B210 a few times but in retrospect I don't think it was necessary.

Hard to tell what's really going on then. How do you know the rears are great? They lock up but the fronts don't? That's typical of air in the front calipers. Can you pump the pedal to get it high and the brakes working? If you can pump them up then you have air in the system. If they just start braking with the pedal low and there's no change with pumping, then you have an adjustment problem. But you should not have bubbles in the reservoirs. Did you install a different master cylinder also? The stock system shouldn't have any problems bleeding the brakes.

Many, many people have problems bleeding the brakes after installing calipers on the rear. Many. Quite often they have to remove the caliper, install a block of wood between the pistons and hold the caliper so that the bleed screw is at the top. There are people on this forum who have spent weeks. maybe even months, trying to get their rear caliper conversions bled.

So what you mean is that you can't get a firm high pedal. The pedal drops too low before you get any braking action, or you have to pump the pedal to get any brakes. ??? One pretty common error that people make is to put the calipers on the wrong sides. They will fit either way. The bleed screw needs to be at the top of the caliper, not the bottom.

There's a spring that brings the pedal up. Can you pull the pedal up by hand?