Zed Head

Somebody bought it from d240zx2, then sold it on eBay to you? And somewhere in there it threw a rod? Wouldn't be surprised to find that that is a DatsunParts/CaliforniaDatsun engine or head. Carefully inspect the cam lobes like Chickenman recommended. Some of the cam lobes might have slipped off of the ends of the wear pads.

I marked what looks like the wipe pattern. Is that right? Looks like what rossiz got from CaliforniaDatsun. Way off, wrong lash pads from the beginning. So you were right to redo everything. Do you know the history of the head? Love a good story.

It might look like this, but in place of ballast, there's a potentiometer. The coil and tach get all the power they need, the tach gets lowered current. Actually, circuit-wise, just splitting the two with no ballast should cut current (by half during Start) on the tach line. So you might actually have to put the potentiometer on the other circuit to increase current through the tach. Where's the guys that do circuit math in their heads?

With a few seconds of pondering I realize that coil probably does need to be in the circuit. Otherwise too much current for the module. But I think that the parallel circuit concept still has potential. Just with both the coil and module at the end.

I've seen threads where people talk about adding a loop to the trigger and I've seen some that imply that the tachs don't like the high current w/o the ballast. If it were mine, I'd probably try running the tach on a parallel circuit with the module, with the ballast resistor and extra resistance to mimic the old system, instead of in series. Actually, I'd just wire in a potentiometer in a parallel circuit and turn up the current until it started working right. The ignition module does the current limiting for coil control on the grounding side. Just split out that tach circuit and let the module control it also. The coil get its full current and the tach gets its limited current. The tach counts the module activity now instead of the coil. Basically, two separate circuits controlled by the ignition module, and separately controlled. . I haven't thought it completely through but that's what I'd be focusing on. Make the combined coil and tach problem two separate ones. Some the above is redundant but I'm afraid I'll lose something if I edit. The tach just needs to see when current is flowing through the coil, and it neds a certain signal strength. It doesn't necessarily need to see the actual current though.

Check for vacuum leaks. Ripped, disconnected or loose hoses. All air that enters the intake manifold should pass through the AFM. The "backfiring" might have actually been popping back through the intake system. Did it dothis when revving the engine or while it was just sitting? The low idle is a sign of a vacuum leak also. Small leaks cause the idle speed to increase, then bigger ones cause it to drop. Really big ones cause the engine to die. If it was actually backfiring through the exhaust then it might be a timing issue. It's not clear if it ran well warmed up before and you did something to it or if you never heard it run when warmed up. Also, you said that you tuned it up first, then brought it home. Did you drive it home? Anyway, welcome and don't do anything drastic unless you're sure. And mark or record all of your starting points. Easy to get lost.

Sounds like a bad battery connection. When the starter motor current kicks in the heat will open a loose dirty connector. The low current from lights, pump, etc. doesn't do it. It's why the only huge wires in the harness are for the starter motor. I almost replaced a starter once because of bad connections until I dug in to the memory files in my head.

That's what I was trying to convey. Didn't happen? Sometimes I write too many words.

On the tach problem - it looks like you're using the stock 240Z coil, by your first post picture. And bypassing the ballast resistor. I'm not sure what the resistance of the early "6 volt" coils are but maybe you're passing too little or too much current. Ignition modules tend to pass too little when they go bad so there's hope that the new one will get everything working together. But, not sure that's the best coil for the application in the long run. A 1978 280Z coil would look similar but be designed for a high energy module. The Crane coil works well too, of course. The electronic modules are designed around certain coil characteristics. Maybe get the ignition system where you want it then worry about the tach. Also, "doesn't work" doesn't offer many clues. Totally dead or twitching or just acting weird?

Nice work, thanks for posting the results and the pictures. jmortensen has recommended assembling the struts and suspension without the springs and running them through their travel range on projects like this. If you don't get any binding, you're in good shape. Of course, there is still the compliance of the rubber bushings to worry about when cornering but you can at least measure how much room there is, with some ingenuity. Maybe remove the bushing caps and offset the arms while running through the travel range.

That's why a shot of the piston tops would be helpful. But that shot of the head shows residual rust everywhere.

The distributor pulls out very easily. Things will make sense once you have the new one, or if you pull the old one before hand. Still curious about what the real issue is. If you're new to engines, it's easy to break or mis-adjust one thing while you're focusing on another. But we all get the urge to DIY. Get back with details if you want some specific advice.

Is that immediately after you unbolted it and pulled it or did it sit for a while? The cylinder sealing ring areas look rusty, like the head sat on the head gasket on the block for a while, unbolted. Should be somewhat shiny where it sealed correctly and dirty where it leaked. Do you have pictures of the head gasket and block? The head gasket itself usually tells a story.

I guess they are. Didn't know that. I like to confirm my suspicions before replacing parts. You didn't really do that, you might have been fine with a lash adjustment. No biggy, just personal preference. Don't throw the old parts away, the rocker arms can be reground. http://www.courtesyparts.com/oe-nissan/13257w0300

Quoi?

This atlanticz writeup shows how the distributor is designed to fit only one way. Since you're just doing a swap of identical distributors you only need to look at a few pictures. The rest doesn't matter. Once you get the new one installed, timing is easy. If you don't have a timing light, consider buying a dial-back light. You'll be able to quantify full centrifugal advance. http://atlanticz.ca/zclub/techtips/distributor/index.html Best to break your project in to its pieces - install new distributor, set initial timing, characterize new distributor, modify new distributor. Where'd you get the reman? Just looked back through your thread though, and see that you never reported the engine running after the initial ZX dist. swap. So, overall, it's not really clear where you're at. You might summarize what's happened since Post #1. You might be working on the wrong thing.

Do you run the engine with no air filters? Just wondering. It may not really matter, unless you have plans for the car.

All those two screws really do is hold the injector upright and keep it from blowing out if there's a backfire, and add a bit of pressure to the seal. Not very accurately placed, the thick rubber insulator rubber allows lots of misalignment. Just saying, if you get to a point where you see it's not perfect, it may not really matter. If you go with later model o-ring injectors in the future you don't even really need the holders and/or the screws.

Looks like one of those junkyard prowlers. Maybe found a window and made up a story? Could just be a factory window replacement from the 70's. Where's Chickenman? His eBay name makes me feel funny -

Thanks. I was serious, I didn't know what the m was for. Makes sense though. Part of the overall monitoring, profiling, and mind-control programs. I clicked. Isn't FricFrac associated with McKay? Or maybe he is McKay. Pretty sure they're connected though. People like FricFrac's stuff.

What is "m.facebook.com"? Is it a new Facebook thing? Never seen it. The new ransom-ware bug makes me nervous.

Full open throttle high RPM advance is determined by initial + total centrifugal. It's really a function of the distributor's parts. Your question raises a point though - there are many timing advance variations described in the service manuals for various cars but one-distributor-fits-all at the parts stores. You won't know what you have until get it and measure. If you have a stock factory distributor and everything works right and is lubed up and not rusted and/or worn and you like it, you could just swap over the E12-80 module. But a stock factory ZX distributor, or a reman, probably doesn't have the advance characteristics you really want for your performance engine. The vacuum advance canister can be swapped over if you like the old one better. But you'll need an idea of what's right for your engine. Probably best to just install the new one, get the engine running and set initial timing to the factory idle setting. Very easy to do with a timing light. Then measure full vacuum and full centrifugal advance. If you have a dial-back light, centrifugal is very easy. There are some tricks you can use to measure if you just have a basic light. Post up your numbers and let people advise you on what's best for that engine. Ignition timing is a whole separate world to play around in. The basic idea of setting timing is to run the engine at idle speed and turn the distributor (with a loose clamping bolt), to advance or retard timing until the marks line up where you want them, on the damper pulley and timing tab. Tighten the clamp and you're done.

Makes sense. Not many of us measure things that work, although we should. I'm not aware of what you would measure on the "match box" though. The modules are hard to diagnose without a tester. There is a test procedure in the FSM's for the other parts of the system.

"stroker" is irrelevant. Unless you only want to talk to guys who have one. The ZX distributors have other weaknesses though. Why do you think it's the module? The stator magnets seem to break a lot, and they actually sell a replacement bushing for the dizzy shaft.

Thanks for getting back. So basically, you didn't check valve lash, you just replaced those parts based on the ticking noise, and the appearance? Pictures would be neat if you still have the parts. And where did you get genuine Nissan rocker arms? My impression that they're NLA.