Zed Head

You could browse the wiring diagram, or the smaller versions in the Electrical chapters. Wiggle some wires in the meantime. Loose connections might be the cause of all of your problems.

Cool. Thanks Chas. Much easier to find now. I "commented" in the Download area and linked back to this thread, for the back-story..

I've found that is you want a photo, people are more likely to get one for you if you provide one yourself, first. An even exchange. Aside from that, it doesn't really matter as long as the electrical circuit is connected to the coil's positive post. Use a meter and make sure that the B/W wire is actually connected to the positive post.

The outer holes, or slots, aren't very accurately placed. I've dinked around with several manifolds. Even with the three center bolts in, the manifold has a bit of wiggle room. The curved surface of the clamping washer seems designed to take up the misalignment. Good luck. There's not much room to work in there. The sleeve idea is a good one, maybe you can jam it to one side to center over the stud remnant. If I was going to do another I'd try that.

Forgot to say, one sign is that the tach needle doesn't follow engine speed exactly. So if you see that needle jump but don't hear the engine speed up...not good.

The tach behavior is a sign that the igniton module might be going bad. You might try the GM HEI swap. It's cheap and you can actually do a temporary install by the coil to check it out. If you want to do a clean permanent install, check this thread out.

Hey EuroChas, I am about to link to this thread for someone that might be having a module problem. I'm pretty sure that your .pdf file is not in the Downloads area. Do you want to give it a look-over and upload it? It's definitely worth a spot there, probably in Tech Articles. @EuroDat

p.s. went and looked at my old 76 4 speed and there's a boss for the switch but it's not even drilled.

Are you assuming that the neutral switch is normally open? I've never heard of one. And, on using the FSM for information - I checked my 76 FSM and it says that I too should have a neutral switch, but I didn't. And it doesn't indicate the top gear switch even though the Electrical chapter shows it, and I did have one. So that source is suspect. Could be that there's no such thing. Translation error maybe. I can't find anything that even indicates what a neutral switch circuit would be used for. No lights or emissions stuff shown. I've never seen one discussed on anything but an Automatic car. Good luck. You could always use a closed switch to actuate a relay if you need a normally open function for something.

I suggested engine vacuum just as a way to see what full advance would be and to verify that everything, including the breaker plate in the distributor, is functioning. It's a simple quick test, intake vacuum at idle is very high and will max it out. If you want to generate a curve like those in the FSM then the pump is the way to go. Don't forget that there are two parts to vacuum advance, the diaphragm in the actuator and the breaker plate. The diaphragms get brittle or stiff, and can split, and the breaker plates get stuck.

What's the back-story? Blow up an engine? You might add some usage info. New, slightly used, XXXX miles, etc. Some of those parts can be had new for decent prices.

I'm overdoing it but last thing - use carpartsmanual and find the part number. Looks discontinued but somebody will have it. Looks like zcardepot has them. https://zcardepot.com/electrical/switches-and-relays http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-case/4-speed/from-sep-71 http://www.thezstore.com/page/TZS/PROD/21-2181

But 73 has two. Fascinating!

More from the 1972 FSM, MT chapter - they only say to disconnect a single wire. Love a good puzzle.

Many of the emissions era cars have a top gear switch, for the vacuum advance control solenoid.

You could set idle to 900 (the point that centrifugal starts to kick in - 2 x 450 [average]) or lower then connect the vacuum hose to a vacuum port. This would give full vacuum advance. Or use your vacuum pump. You'll probably have to reset idle speed to below 900 since advancing igntion timing typically increases idle speed, which will cause the centrifugal advance to advance timing also. Or you could use the curve from the FSM and subtract out the centrifugal part.

I wondered about the Vinny Bedini comments. He was before my time but there was some overlap, with Kathy & Rick comments. I've only had my Z for about five years but a lot of people that were deep in to the cars are moving on to other things. http://www.classiczcars.com/forums/topic/36343-bob-sharp-racing/ http://forums.ctzcc.com/viewtopic.php?f=10&t=8221 http://www.wolfcreekracing.com/index.php?option=com_content&view=article&id=3&Itemid=12 http://www.ctzcc.com/images/bedini.pdf https://www.linkedin.com/in/vinny-bedini-b8716923

I know that these are hard to find in un-curbed or -shrubbed shape. This one looks decent. http://portland.craigslist.org/clc/pts/5819794925.html

Saw this ad and did a few double-takes when reading through it. Kind of funny. Sorry if you're a member here. http://portland.craigslist.org/mlt/cto/5808738675.html '77 Datsun 280Z with Track Car Potential, Needs Motor, New Exhaust Sy - $7000 (Portland) This Z is a head turner, and is perfect to be built into a fun track car (for open track day, not racing). It needs a new motor due to a connecting rod coming loose. The car has a 3-speed automatic transmission but, again, ripe to be rebuilt for the track. Despite the current motor issue, this car is otherwise in great condition:gold with black racing stripevirtually rust-free 109,547 mphnew exhaust system (see below)tight handling and suspensiondent free bodyseats in very good conditiongood brightwork and glassworking CD player and custom speakers, digital audio inputheat works, A/C does notglass/door sealing done recently to prevent foggingDatsun Type HLS30VIN: HLS30366369Engine details: L28, a 2,753 cc (2.8 L; 168.0 cu in) 12-valve engine. Bore is 86.0 mm and stroke is 79 mm. The basic L28 is carburetted. Chassis No. HLS30 -- 366369Max. HP/RPM: 170 HP/560 OR PM (SAE)The entire exhaust system was overhauled in 2014 by a Z car master, Vinny Bedini of Bob Sharp Racing in Connecticut. (Vinny is mentioned on this forum http://www.zcar.com/forum/10-70-83-tech-discussion-forum/294382-bob-sharp-33-wheels.html and there's more info on Bob Sharp Racing here https://en.wikipedia.org/wiki/Bob_Sharp_(racing_driver).) Vinny also replaced the wheels allowing for slightly larger than the original tire size. So the wheels, tires and exhaust system are all new and built by a Z master.

It really depends on your plans, your skills, and the local market. I'd pay more than many people would for a car with no drive train because I have extra parts and I feel comfortable doing that kind of work. Others on the forum are more comfortable/skilled at body work, or electrical, or interior. Some have local shops that they know of that can do certain work for a good price. Best to put a plan together and a list of resources, with costs. The car, like that one, is just one small part of a project. Most of use have spent more money on parts and labor than on the original car.

I think you're right. The average of 375 and 525 is 450. Matches the starting point of the specification (Post #2). Maybe it's a standard method for showing distributor curves, in the 1960's/70's.

And the centrifugal advance mechanism should have a number stamped in to it that indicates maximum advance. You have to remove the breaker plate to see it. Won't tell you the rate but should show max. In the big picture though, with the changes in fuel composition, the fine details of what Nissan did may not matter much. As far as how to tune your engine.

Actually, I see how confusing it can be. My previous post may be worthless. Don't forget to double the distributor numbers to get crankshaft numbers. I would seek out the proper curves for -53 also.

I think that the two curves are for two different engines, and transmissions. Page EM-34. Match the spec. to the final advance on the curves. Edit - added the comment about the transmissions. Manual versus automatic. Edit 2 - My image is from what's supposed to be the 1972 FSM. The distributor numbers don't match yours though. I would not trust that " D612-52 that I understand has the same curve. " is true. Overall though, I think that each one of those curves is meant to be used alone. No adding together, unless you want to calculate centrifugal plus vacuum.