Zed Head

Directed at the second sentence of the first post.

Every FSM has the distributor curves in the Engine Electrical chapter. And the curves aren't specific to the distributor, they are tied to the combinations of parts. There are no "Weber" curves. Here's 1972, for example. A good starting point.

Damn, the site is getting Gallery imaged again... Hate it when that happens.

People report mixed results when raising the compression ratio by using flat top pistons. Apparently, fuel quality differs across the states so some people get knocking and others don't. If you don't shave the head the N42 or N47 gets you almost 10:1. http://www.ozdat.com/ozdatonline/enginedesign/ There are so many opinions out there it's crazy. Some people like the rumpety-rump cam noise, some like the 7500 RPM screamer, some like the torquey 3.1 liter engine. RM needs to decide what makes him smile, I'd say, and get those details.

Are you sure it's not 0.4? Regardless, it should be battery voltage, disconnected, with the key on. If you get in to the wiring diagram you'll see that the jumpers in the atlanticz diagram are just meant to route that Lamp circuit directly to the T plug. You could short across the T plug and you'd have a "one-wire" system. Your charge light won't work right though. I think it might drain your battery too. Even if you get it to work you might have a problem with the brake check warning lamp relay, draining tour battery. I had the problem with my 76, after using the atlanticz diagram. They changed it in 77 I think, but not sure exactly how. It might be that the atlanticz diagram is not right for your car, maybe try the 76 diagram. He actually puts a disclaimer in there, I think. CO got deep in to the 77 and 78 waring lamp in a past thread. Eventually I just said screw it I need to know how this all works, and I ran my own S wire, rerouted the power to my warning lamp, and only used the L wire. It's easy to check everything with a meter. Find the L wire, confirm continuity to the L terminal at the T plug, jumper those two together. Pick any S wire, there are 2 or 3 constant power wires at that plug, if I recall, jumper one to the S circuit at the T. Overall, you just need to know which is L. S is easy. Here's a 1982 alternator drawing. The wire colors are probably different but the positions will be the same.

site, the N47 head is essentially the same as the N42 head. Nissan added the exhaust liners for cleaner emissions but didn't change anything else. So if you're not planning to do any porting work, or add a turbo, the two are about the same. The N47 typically comes with the oiler cam also. With carbs, exhaust and cam are probably the simplest power increasers. Increase air flow through the engine. After that, port work on the head. But even with port work, it's mostly intake, not exhaust. There is a lot out there about how effective compression ratio increases really are. They don't do much, on their own. I would read up on CR and its effects before going to the trouble of installing flat top pistons. There's a lot of money you can spend without really gaining much. Plan first then act.

It looks pretty straight, except for the fender. Northwest rust comes from standing water, unlike Northeast rust which comes from salt spray. I have two rust holes on my 76, one from standing water under the driver's seat, and one under the battery from the battery electrolyte. All of the other metal is solid. So that nasty quarter panel hole could be the only really bad spot. It's possible. Edit - I could take a look if somebody was really interested.

You probably left the blue wire disconnected in the engine bay. You should have a wire from the coil negative to the C terminal on the HEI, which you do because it works, and a blue wire to either the C terminal or the coil negative (since they're connected anyway) that runs in to the harness. It ends up back at that resistor, which is connected to the tach. It just lets the tach "see" what's happening at the coil.

On further review I can see where things don't add up. The charge light coming on implies that there is grounding through the alternator. But it might not be. The Charge light can ground anywhere.

It's over in NoPo (North Portland). The license plate numbers don't match. He does have a title though, which is good.

A decent deal on a full setup. Don't know Maltby. Looks close to Seattle. https://seattle.craigslist.org/sno/pts/d/z-motor-trans-runs-fantastic/6556176333.html

Isn't it easier to stick a voltmeter probe in to the T connector while everything is installed? The thing is already bolted up. No T plug L circuit voltage = no charging. He already showed that it will charge with the old connections through the regulator so it seems like a lack of current on the L circuit. He could even add a jumper wire from the battery to the L pin as a bench test. Except the bench is the car.

Aren't we at the point where he just needs to unplug one of those bullet connectors and measure voltage with the key on? That's my thought. Seems clear it is the resistor, right?

People ask for advice about price all the time on the forum. If your post was on Craigslist somebody could start a thread here asking if $800 was a fair price for a used 280ZX 5 speed. I was politely suggesting that it's kind of high. If you know the mileage why not post the number? It makes a difference in making a sale. Good luck. I'm doing you a favor.

Indeed it does. The 1975 FSM wasn't available for quite a while, the 76 was a proxy. Nice that we have a correct copy on CZCC. I think that mine came from xenonzcar. The 75 FSM looks like it was typed out using a home-made typewriter. The worst quality text. Maye some sort of translation machine.

No, I'm pretty sure the wires are blue. This is from a 76 diagram that a member put together. I think that 75 is the same. It's smaller than whatever is in that pile of tape in your picture. Edit - wait, I see that the input wires in your picture are blue. 75 was the first year of EFI so they did some funky stuff. That's probably it. Edit 2 - a picture would be interesting. The 76 and later parts are very nice, plastic covered resistors. Almost a shame to cover them up in tape. Yours looks clunkier. You can measure resistance to verify. Actually you don't even need to remove the tape, with the connectors right there. But still...

The second video on this link is pretty impressive. I think that it would be a nice unit for triple Webers, which, as I understand things, don't usually use vacuum advance. With tunable timing, you could actuate vacuum advance at high vacuum and mid to high RPM, which would be like highway cruising, for better smoother running. They've also added an anti-theft feature, which is a bonus. I'd show the RS guys this video and the specs and see what they think. http://123ignitionusa.com/123ignitionusa-perfect-timing-for-your-classic-car/ Here are some better specs from the Dutch site. The USA site has dumbed-down the site, it's not worth much now. It looks pretty good, automatic "dwell", aka current-limited, high energy ignition. And they've gotten better since they first showed up. So they'll probably be around for a while. http://www.123ignition.nl/product.phtml?id=221 p.s. you should tell the R S Speed guys to open their Facebook page to the public. I can't see anything unless I log in. Might never log in to Facebook again. But I'll still look at other people's pages.

Just curious, but have you owned a Z or ZX, and driven one? Or did you just pick up an old car? No offense intended. I've not heard anyone call $800 for a used ZX 5 speed and flywheel a fair price. Might be different up in Buffalo though. Seems like you might be new to the world of Z's. Maybe surfing the California Datsun web site and getting wrong impressions. Did you drive the car before deciding to part out? Then you'd know more. Do you have mileage on the parts? And is the flywheel 225 or 240mm (coupe or 2+2)? Good luck.

Hate to badger you. But if you can put all of the small details together you'll have a better chance. Your problem is uncommon. Doubtful that anyone will have a "that happened to me" answer. You never know though. I'm going to guess that something has shorted in the voltmeter and and is somehow powering the pump power control relay and the Charge lamp. Not sure how that would actually work, it's a puzzle that my brain doesn't want to work on. Does the meter smell like burnt wires? Try unplugging the voltmeter. That might fix everything, except you won't have a meter or a Charge lamp. You'll have to take the meter out, it's pretty easy. It comes out from the back. Described in the FSM. If you have dexterous fingers you might get it unplugged with just removing the front panel.

I knew that there would be more clues. I would sit down with the FSM and look at wiring diagrams. And put the clues together. Does the Charge light (that's what most call it, not a dummy light) go out when the fuse blows? Does the pump stop?

Still wondering what the timing issue is. There really area a bunch of different ways to control spark, and a bunch of different opinions. Like iphone vs Andorid.

Did everything work correctly before? Is connecting the jumper box absolutely the only thing that you did? No other things that "couldn't possibly be" part of the problem. Seems like you might have short-circuited something in the pump power control relay, it uses the alternator charge circuit as a control mechanism. You could try unplugging it and see what happens. I think that the relay is behind the metal box by the battery. You'll have to figure out this picture yourself.

With the key on and engine not running check both pins at the T connector for battery voltage. Sounds like your L connection is not complete. If you confirm that there are several ways to find L and get it connected. S will have power with the key off. Might as well verify that too. All the stuff you're doing at the old regulator plug is just for the purpose of getting L and S connected to the T plug. Might be that you just had bad jumpers. Check for S and L at the jumped plug also.

You should use your super-duper iphone to do some searching. https://play.google.com/store/apps/details?id=com.albertronic.x123tuneplus&hl=en

Here's a Monise/Datsun connection. One of them was a driver for BRE. https://www.datsun.org/fairlady/BRECrew.htm