Zed Head

You can't even swap ring and pinion within the Nissan family, from old to newer - " In addition to the bolt in axle issues, there is another difference between early and late R180s. Early R180's measure 110mm inside the ring gear. 77 and later model year R180s measure 115mm inside the ring gear. This minor change means that the ring and pinions won't swap between the early and later models. If you have an early diff you must use an early carrier, and if you have the later diff you must use a later carrier. It is possible to use a early carrier on a later ring gear with a spacer, but that is outside the scope of this thread. " http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/ Here's John C's first prototype shaft thread. It has comments specific to the different spline count - http://forums.hybridz.org/topic/78123-subaru-wrx-sti-r180-side-axles/ Here's one of the early Subaru diff swaps - http://forums.hybridz.org/topic/73182-subaru-sti-r180-differential-and-axle-conversion-revised/

The sleeves are out there - http://www.amazon.com/s/ref=nb_sb_noss/176-5899364-2390852?url=search-alias%3Dautomotive&field-keywords=Sleeves+Capsule+for+Valve+Stem+

You should specify year of car. 75-77 280Z's had a contact in the AFM to run the fuel pump relay. Also, people often open the AFM but don't adjust it, for cleaning and examination. If the glue blobs are intact it's probably OK. And, there are many symptoms that look like AFM but aren't. MSA summarized them nicely. Read the text at the bottom - http://www.thezstore.com/page/TZS/PROD/11-3040

Some of the "chatter" marks look more like chatter from a regrinding operation. Check lash after a few hundred miles, and then a few thousand. If a lobe is going bad, it will show up. One thing that might be informative on the cam lobes though, pertaining to the valves, is if there is wear on the base circle. If lash is set right the base circle will get a coating of brown, since the anti-rattle springs are lifting the rocker pad from the cam and there's a gap there (the lash). If there's wear on the lobe base, there's a chance the valve seats have worn, or a valve stayed open and got "burned" or warped. Really though, if it sounds good and runs well, you might as well just get another head ready to swap on.

I'd actually looked through the Hybridz thread before but how they fit didn't really sink in (or I forgot). Didn't really think of the rear transverse-oriented sub frame (where the BD rails terminate and weld on) as the rear sub frame. I've been looking at the arched piece that goes over the axles, thinking in terms of a lengthwise frame rail, trying to connect two parallel rails in my head. The rails should probably actually be called bracing, or stiffening ribs, or boxed sections, or boxed bracing. The metalwork in front, where the engine bolts in, would be a sub-frame. I think. The 240Z rear "rail" might better be called a rail (brace) extension. History prevails though. Found another good BD rails thread, describing how to make them fit and weld them in. http://forums.hybridz.org/topic/58497-installing-bad-dog-frame-rails/ I'm almost disappointed that I have a 280Z, with decent shape rails/boxed braces. No good reason to modify yet. Nissan shows where all of the sub-framework is in their Body chapter, as dotted lines. Here's 1972.

Eyeballed my 280Z and the rear and front sub-frames aren't on the same line. Not connected directly either, except through the bend of the floor pan (the bend would add rigidity), although almost overlapping. The Bad Dog 240Z rear frame "connectors" would get someone close but I don't that they're a full direct connection. It's an interesting engineering problem, load distribution/transfer, stress risers, and all that.

That's probably the part. Don't know why he calls them rear rails. He mentions connecting in the description. Apparently the 280Z sub-frames extend further than 240Z (edit - they don't, they're the same length. The 280Z's just use thicker steel and are better braced in general), so maybe not as necessary. OR maybe they're already connected. To the garage... " New 70-73 Datsun 240Z replacement under floor frame rails. Replace those rusty frame rails with these custom fabricated rails. These are two piece assemblies that connect the front frame rail section to the rear frame rail behind the seat. Great for high HP or V8 conversion "

I'm just pointing out that Bad Dog does not appear to provide the solution that John Coffey, professional race car builder, suggested was the second best bang-for-the-buck. That's all, not even debating whether it's truly worth doing or not, just saying that there's no sub-frame connector offered by Bad Dog. I seem to recall seeing the actual connectors on Bad Dog's site in the past, but maybe he doesn't make them anymore. gnosez (Gino says?) is Bad Dog. I'll send him a message and maybe he'll get in here. He already replied on the windshield question. Edit - Sent him a message, let's see what happens.

Sorry, can't get rid of this box, even after starting over. Once you put something in a Reply box it seems to be "cookied" forever. Anyway, the Bad Dog rails don't connect the sub-frames, which is what the goal was I thought. Just looking for the connectors connection.

Does he still? He only shows replacement rails on his web site. http://baddogparts.com/ http://baddogparts.com/index.php?main_page=index&cPath=2_5

Here's what made me think of CaliforniaDatsun. Some of his lobes ran right off the end of the pads.

Didn't mean to imply that you have a bad engine. Could be that somebody just assumed that the lash pads they had were right for the cam. Or they replaced the cam and used the old pads. Looks like they just didn't do the final check. Although, some people will run on the inside of the wear pad to get a little bit more lift at the valves, but yours look like on the razor's edge, not the racer's. Anyway, good that you caught it before real damage was done. Carry on...

Forgot to say, one of the main weaknesses with the Pertronix system (not bashing, just pointing out [obscure pun!]), compared to other electronic options, is that it doesn't do current-limiting. That's why you have to balance the coil and ballast, and I think it's why the tachs often don't work right. The tach is expecting a certain quantity of current. That's what the game is, finding that quantity. I think.

Actually, in your case, looking back at your specs. I don't know if my suggestion offers anything. Running the extra line to coil positive will reduce current through your tachometer trigger loop. Seems like you need more current, or an extra loop (but I don't know for sure). If my guess is right, the extra line will make your problem worse. It will drop current on the tachometer circuit. Shouldn't hurt anything though, it still runs power through the coil and Pertronix module. I might connect the line first and see if the problem gets worse. The tach might quit working completely due to low current. If it does, that would imply that you need less overall resistance, maybe a lower resistance coil. If the tach works better that's a clue that it was over-currented at high RPM. Maybe overheating. A way to run more current through the tach loop is to use a lower ohm coil. That would be on the same path as an extra loop on the tachometer. Might be a worthwhile experiment. The Pertronix situation is interesting because with the ballast and tach in series as they recommend, the overall resistance is higher than just the coil resistance. So they recommend a 3 ohm system but don't really address the ballast and tach effect. Ponder the ways to increase or decrease current through the tachometer circuit. It's hard to get a complete logic path to a solution because you don't know how much resistance the Pertronix module has when grounded, plus the ballast resistor is actually a variable resistance device. It heats up at low RPM since dwell time is longer. SteveJ probably has the answers and could critique my suggestions. He's a tach guy. Short answer is "I don't know", I'm just brainstorming.

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.