Tennesseejed

Whenever an engine runs well, then then runs crappy, and then miraculously runs well again, my thoughts go immediately to electrical issues. One thing that stands out in the OP is leaving the battery hooked up to a trickle charger all Winter. I'd start with load testing the battery, check for corroded terminals, perhaps condensation in the distributor cap, etc.

inline6, sorry to hear you are having some issues with your 3.1 build. Your engine build thread is a goldmine of information. Couple of thoughts that may not be worth anything: 1. You say that the rocker wipe pattern is good - and holding the rocker in person is certainly better than viewing a small picture - but the first picture of rocker #10 appears to show the lobe contacting the rocker off the edge of the pad. In any event, your lobes are clearly picking material off of your rockers. 2. I know that you consulted many professionals in your build, and Lord knows they know more than I do, but an installed spring pressure of 54# for a high revving engine seems awfully light. As engine revolution increases, and the combustion event timing shortens, you generally need more spring pressure to keep your valves from floating. Perhaps your ultra light titanium valves (and valve train components?) permit such a light spring pressure, but I would expect to have a closed seat pressure in the neighborhood of 154# and up to 290# open (~100# more than your springs) for a +7000K redline engine. Just my .02. Hope you find a simple and inexpensive solution.

Interesting thread. Any person who comes to HybridZ to read and post a little learns quickly that they bear at least some burden to ask a nominally intelligent question. While I don't recall having done it myself, its not uncommon for the general membership to give both barrels to a first time poster with some innocuous, ordinary or mudane query. This site does have an attitude and seems, by and large, to be self-policing. I like that. To the extent management perceives a problem with the site being overrun by dimwitted peasants, I guess I don't see that. Or at least I don't see the low information poster substantially cluttering what is an otherwise invaluable, free public resource on Z cars. The chassis specific forums, where most of the wheel offset and 'slamming' questions originate, seem to allow for more generalized discussions than the tech specific sections. There is a troubleshooting specific subforum for the 'help, my car doesn't start" questions, and the tool shed for posts for total garbage posts. I think the site works very well. Despite not being a spring chicken myself (45), and freely admitting to the desire of developing into a Class A cranky old man before I push up daisies, a few thoughts in defense of the new poster with simple questions: 1. We were all beginners at some point in our life. At least some of the new posters, even the ones with dumb questions now, will eventually overcome and meaningfully share in the common hobby that binds us together. While I have no desire to rub internet elbows with a bunch of 'ricers' on a regular basis, does a legitimate desire to protect the Hybrid Z temple of knowledge justify kicking sand in the face of every 17 year old who just purchased a rusted out 240Z and wants to know how to wire his starter? 2. Sometimes you just gotta ask a simple questions. The wealth of information here on HybridZ is deep; it is also sometimes conflicting or so theortical and esoteric so as to not provide a straighforward answer to your question(s). Electronic questions, such as 'how do I make my tach work with MSD' or 'where does the white wire on the HEI module go,' will not always reveal simple answers after an hour or two of searching. There may be no "best" here on HybridZ, and engine building may be as much art as science, but many questions related to Z cars do have right and wrong answers. Not every person can rebuild a 5-speed transmission while blindfolded. I don't think someone asking "why does my transmission pop out of reverse" should be out of bounds. 3. It's o.k. to mingle with the humans a little. I completely respect that HybridZ is a knowledge base first and a social site second. But what's the fun of poring over dozens of pages of search results only to find your own answer and then quietly go into the night. Sure, there are garages, and build threads and project threads aplenty, but the 'search first, ask questions second' approach, when taken to the extememe, has a chilling effect on conversation. To be clear, though, I am fully onboard with requiring a poster to bring a modicum of reasoned thought to the table when posting. I suppose that I am just trying to say that if the goal of turning a wrench on a Z car is to create a vehicle that provides the driver with a joyous and exhilerating driving experience - as mine does thanks to this site - its only natural to want to spend a little casual time sharing your happiness with others and getting a pat on the back, or vice versa. That this sort of commentary doesn't relate to optimum piston to valve clearance in consideration of the quench characteristics of the P90 head, or derive the airspeed velocity of an unladen european swallow, doesn't mean its a bad thing. Just my .02. Thanks to the keepers of this great site. Sincerely, TennesseeJed Chairman of the Dumb Questions Department

Hello OilKiller and welcome! Having started with a non-running Z project myself a few years back, I'm actually a little jealous that you have so much troubleshooting in front of you. Maybe I'm a bit off, but I really like fixing things and you appear to have an excellent platform to begin with. HybridZ is a spectacular resource and you will find answers, tips, hints and theories on almost everything related to Z engines. If I were in your shoes I would make my first objective to get the engine to start and run in a reliable fashion. Megasquirt is an excellent aftermarket EMS (I use it) though several other brands are available. While MS1 or MS2 could serve your needs, buying a preassembled MS3 unit is probably your best value. That way you can grow into new features such as sequential injection. In the short term, I'd run a fuel only MS install saving EDIS or another ignition system for down the road. Getting you car to start and run, if only around the block because you have no lights, is a tangible and rewarding first goal. As you have probably already learned, the '75 Z ignition is controlled by the ICU; Fuel management by the ECU. Adding Megasquirt replaces the ECU, but you should look into the '81-'83 ZA dizzy (HEI module) or MSD6 to replace the ICU. Factory service manuals and electrical schematics can be found at xenons30.com (among other places). As you describe it, your engine may have issues. Gas could only get into the engine oil if unburnt fuel is passing the piston rings into the block. And this would only happen if (1) you have an injector that is stuck open and/or (2) you have a cylinder that is not firing. Maybe you have coolant in the oil from a leaky head gasket? As far as the electrical system, since you are an engineer, let's hope you're an EE. IMO, the '75 Z electrical system was designed by the devil herself. Thoroughly over-engineered. Part of the fun of installing Megasquirt is ripping out ~50 yards of wire from the original EFI system that you'll never need again. You'll simply have to address the electrical bugs as you go. I ended up buying a trickle charger/starter because I got so tired of swapping batteries and jump starting my car until I got the electrical system debugged. Works great now, but boy howdy it was a pain in the ass. Good luck and keep us apprised of you progress.

Xnke, the last Z alternator I bought was ~$50. The last external voltage regulator I bought (locally) was ~$115. Without question, my primary goal was to simplify and stabilize my electrical system. Folks that want big amp alternators might look into the GM conversion too. @cd1105, sorry to hear you haven't worked the bugs out of your charging system yet. I've had a little to much wine tonight to talk electrons, so I'll try and look at your issue tomorrow and give you my thoughts. Let us know how the alt test goes. Last alt I bought - for a Dodge pickup and it was guaranteed 100% tested - had a bad diode and went back the next day. @cd1105, NewZed pretty much answered your question in Post #13. The W/R wire on the back of the alternator is the output, and needs to be attached to battery positive. If you haven't already removed/tested your alternator, I'd put a voltmeter on the W/R terminal or wire with the car running and see if you are getting more than battery voltage. If so, you solution might be as simple are connecting the W/R wire to battery positive.

I'd guess there is a FI Ford 302 in the 911. *shrug*

Sounds like a pretty good deal to me. I'd ask him to pull the valve cover so that you can look at the cam lobes. With a little searching you can see what a wiped cam lobe looks like and also where the lobe wipe pattern should be on the rocker. Not uncommon for someone to put a cam into a L28 without also installing springs to match (if large enough to be necessary), refurbing the rockers, and adjusting the lash pads to set a good wipe pattern. If it's got a bad lobe or two, your also buying future headwork.

Jacob, can you fix your links please.

Jamal, Missed your post. Sent you a PM.

Sorry fellas, I didn't get any email alerts that people had responded to this thread. Here is a pic of what I am needing - the '81-'83 piece. I have the correct plastic gear to match my rear end but need everything else.

Looking for the speedometer gear unit from a ZX 5-speed. They are slightly offset from the 280Z 5-speed and I'd like to get my speedometer working again. I have the right colored cog/gear so it doesn't matter what color cog you have on yours. I can use mine if necessary. Thanks, Jed.

Test the DC voltage across your battery terminals with all wires attached. Turn your car on and let it idle. Test your DC voltage across the positive and negative battery termainals again. You can also rev your car a bit by reaching over engine and cracking the throttle. If you're reading ~14.5VDC while the car is running, your alt is charging. I'd have to look at the schematic to be sure, but the charging light might be isolated by cutting the other wires from the external regulator. On my '75 280 the voltage gauge still works as it did before.

I'd do the shims myself, but you might as well go through the exercise with the headsaver. What is your compression ratio now? The Z Engine Calculator can help if you don't have it (search on here I think its pinned in the downloads section). Calculate your current compression ratio and then calculate it with the cc loss caused by subtracting the volume of the headsaver. Also depends on what the engine is for. I.e., if you are building a high performance/track engine you would also want to consider how the headsaver might effect cylinder combustion. If this is a stock rebuild using dished pistons, this probably wouldn't matter as much. Here on HybridZ there are no right or wrong answers, just lots of information available to help people make informed decisions.

Not a lot of Z cars in Alaska and certainly a few in town better looking than mine. Regularly get a compliment or shout out at a stop light. Came out of Fred Meyer not long ago to find a folded note under my wiper. Two words. "Nice Car." With a smiley face too. : )

MSA sells .015" cam tower shims. Given that your head may have had a prior mystery shave, probably a good idea. Somebody in Washington - Delta Camshafts? - sells refurb rockers for ~$4 a piece. Compared to NOS, I'd bet that is a pretty good deal. I purchased them for my top end rebuild and haven't had any issues. Most 'new' Z parts are awfully expensive. The headsaver .020" gasket that someone mentioned will correct your timing chain geometry, but will also sap your static compression. On the other hand, shimming your cam towers might alter your rocker geometry by shifting your cam lobe wipe pattern. 15 thou will not move the lobe pattern much, but it will a bit. Off the top of my head, the lobe pattern should move toward the pivot side since you will need to raise the rocker ends a bit to set your valve lash. Most people prefer to have the cam wipe towards the pivot end, though, so this would be a good thing and you can also reuse the stock shim pads.

Since the diode is wrapped in electrical tape, a pic isn't going to help you much. Sorry to be non-visual but the diode goes anywhere inline with the Switched 12V wire and the "F" wire on the alternator. The doide has a white line on one end. This end of the diode goes toward the alternator, i.e, attached to the "F" wire. You can't harm your car by installing the diode incorrectly or by not installing it at all. The diode simply blocks feedback current which causes the 'run on' syndrome. Good luck.

I know this thread is a little old, but I thought I would put my knowledge in here so that others with off-idle hesitation issues might find it later. My car (MSII/3.57/Fuel Only) was having a noticeable hesitation off idle. The culprit was related to RPM spikes at low RPMs. No issues above ~1500RPMs. Just tapping on the throttle was causing my RPMs to shoot briefly to 8K or 10K. By turning on noise filtering, as well as tach period rejection (set at 2ms/30%), virtually all of my off-idle hesitation issues went away. This would only be helpful to people who either see RPM spikes in their data logs or, as I first noticed it, saw my RPMs jump wildly off-idle when viewing Tunerstudio/Live VE Analyze.

That's a good point. Some models may have loads that are only part of the charging circuit when the car is running (the voltage regulator is an open when not operating). And by removing the open (voltage regulator) those loads become part of the circuit when the car is not running. Ergo, the dead battery syndrome.

I recently did the ZX alternator swap on my '75 280Z and thought a brief write-up might be helpful to the HybridZ community. One of the best, and most popular, alternator upgrade threads is found on AltanticZ: http://atlanticz.ca/zclub/techtips/alternatorswap/index.html While the write up looks comprehensive, it doesn't work for the '75 (or at least my car). Here's why: This picture is the harness side connector to the external voltage regulator. Notice anything? How about five wires. There is no #1 wire on my harness. Because I wasn't able to find any information on HybridZ or the interwebs about the 'five wire' conversion, I want to pass my learnings on to other who aspire to ditch their external voltage regluator. In addition, what I learned de-mystifies the alternator swap for folks who aren't experienced with electricity and applies to any model Z with an external regulator. Here is what you need to do: 1. Source an '81-83 ZX alternator and install. Wire the alternator exactly as your current alternator. There is a battery wire, an earth ground as well as the "T" connector. These wires don't change. 2. Access your voltage regulator and disconnect the six wire connector. Clip the wires on the harness side connector as close to the connector as possible. 3. Using a voltmeter, find the wire that has battery voltage (+12VDC). One wire will have battery voltage on it without the key in the ignition. This wire is connected to the wire that connects to "N" on the T-connector. "N" and "F" are marked on the back of the alternator. For example, on my '75, the "N" wire was yellow and the white wire going to the harness side connector had +12V. Connect these. Done. Don't be concerned about wire color. If the wire has unkeyed +12VDC battery voltage, it gets connected to the "N" wire on the T-connector. The color of the wire doesn't matter. 4. Determine the color of the The "F" wire on the T-connector. This wire gets connected to either (1) Switched +12VDC (Key "ON") or (2) Switched +12VDC (Key "START"). You determine the correct wire(s) by testing each [skip Black because its ground and the battery +12VDC because you are already using it] to see if it has battery voltage when the key is switched to "ON" or "START" respectively. To test for key "START" disconnect the solenoid wire to your starter if you don't want the car to turn over. You can connect either the switched "ON" or "START" to the "F" wire. However, if you have a switched "START" wire, try that one first because you may not need the diode. 5. If your car does not have a switched "START" wire, as my '75 did not, you need to purchase and install a 1N5402 (I used 1N5404) diode. The diode has a solid line on one end. Here is all you need to know about installing the diode: The solid line end of the diode goes toward the alternator. Connect. Done. I can't understand why anybody with an external voltage regulator has not done this swap. Especially when I spent $115 for my last voltage regulator and the reman ZX alternator was only $50. Edit: Edited to add that the switched START wire may not need the diode rather than will not need the diode. My car did not have switched START power at the harness connector so I cannot state that for certain. Just a hunch.

In terms of fair market value (as opposed to trades or DIY) is this more, or less, than $2,000 in crank work? Absolutely beautiful. Do want.

Yes, but the orginal question was whether the OP should change his cam timing to compensate for the additional chain slack. I'm saying he should time his cam normally. And that I don't know how much slack the Kameari can accomdate so he might consider asking the source. That's all.

Good thought, but advancing your cam timing does not solve issues related to extra timing chain slack. Except, possibly, when your engine is decelerating quickly and the velocity of the camshaft exceeds the speed of the crankshaft, there will never be slack on the 'down' side of you timing chain. Instead, all of the slack will exist on the 'up' side of the chain which is why the stock chain tensioner is where it is. If that makes sense. Advancing your cam timing does not effectively split the difference of the timing chain slack in actual operation. If you advance your cam timing, as another poster stated, you are lowering the powerband designed into you cam. I don't believe the stock tensioner can handle the extra slack you propose. Not having any experience with the Kameari tensioner, I'd call them and ask. If they have doubts, get the cam towers. Cutting .080 off the P90 head and installing N42 valves is a pretty popular mod for Z car owners. Somebody probably makes them. JMO, but I'd get the shims and have the designed cam timing geometry. Good luck with your project.

Did you or someone else time the cam when you installed the new timing chain? I think one link equals 20degrees on the cam sprocket. If you have a mircometer, that is what I would rule out first.

I believe that going to two squirts simultaneous will double your PW. 1.6 - 1.8 is pretty short. I experimented with every possible to injector setting (1 simultaneous to six simultaneous) last year while trouble shooting some idle issues. Quite frankly, I found two squirts was best and there was no difference between simultaneous and alternating.

You're using a narrowband O2 sensor? I don't know if you can tune effectively with a narrowband. EGO active above 160 is good, but double check to see if any warmup enrichments extend beyond 160F. If so, EGO might be fighting with those. If you have trouble with smooth idle, you can also drop your "active above" down to 600RPM or so. This works particularly well with Analyze Live. I think controller authority of 15% might be a little high. What you are doing is allowing large corrections instead of small, incremental corrections. I think the manual says a high authority value is good for a rough tune, but once you have a pretty good tune, a high controller authority might result in overcorrection. FWIW, I though installing MS was the easy part. Certainly the more challenging part is the tune. Hang in there. It can be frustrating, but in the end it's pretty rewarding. Last couple of thoughts: Try to manage you tunes in an organized fashion. You'll probably have 10 or more soon enough. Change one thing at a time and save the old tune so you can revert back if you mess up. Also, if your like me, you'll be tweaking your tune almost constantly for months. And then, as soon as you think its good enough, a week later you'll start fussing around again. Constant tuning kinds takes away from just enjoying driving the car. Once its good enough, try to leave it along for awhile. Good luck.