NewZed

Did you see lowrider's thread? - http://forums.hybridz.org/index.php/topic/97253-hei-spark-control/page__pid__913356#entry913356 The 8-pin GM HEI module is essentially the same as the 7-pin module except it has a separate ground wire. The relay is to give 5 volts to the B pin only when the engine is running. It allows the car to start with the original static timing, then applies the Megasquirt timing advance when the engine is running. That's all I know.

I have been studying this same setup recently for future reference. I don't have Megasquirt now but am interested in your problem. If I could ask a couple of questions, for my own purposes and maybe to add a little clarity - 1. Have you measured voltage at B to be sure it's actually at ~ 5 volts? Maybe you're overpowering the B pin with 12 volts and that's why you're losing the R pin signal. Just a WAG but I wonder why you're losing your tach reading, it comes from the R pin on the module. I assume that what you mean is that you connect B before starting, hit the key and no more tach reading in Megatune. 2. Does your trigger offset in MegaTune match what you read with the timing light, with B disconnected? Your static distributor timing must be close already if it runs without the B pin. It sounds like mechanically everything is right but either Megasquirt is not getting its information from the R pin or it's sending out the wrong information to the E pin. You must be connecting B before starting, as Matt Cramer suggests, since you don't mention the car dying, just not starting. To Matt Cramer's point about connecting B while running, the diagram on this page shows the use of a relay to disconnect B while cranking, and connect it only while running. http://www.megamanual.com/ms2/GM_7pinHEI.htm About halfway down the page. Hope I'm not muddying things up... Edit - came back to change your to you're...

I was kind of off-base on this anyway. The crank spins twice as fast as the distributor so you'd end up with wasted spark on a single coil. That might be too much for the coil. Unless you used a three tooth wheel on the crank. My mistake. I'll go back to my own business now...

This guy's approach is interesting - http://forums.hybridz.org/index.php/topic/90889-wasted-spark-ignition-no-edis/ Instead of holes and Hall effect, you could drill and tap for bolts, grind the heads and create teeth on the engine side of the flywheel, so you could use the VR sensor and the Motorcraft EDIS unit. A lot of work (not too much if you went 6-1 like he did) but would allow you to stay away from the front end of the crankshaft, but get the same result. No comments on wiring the three signals together and running one coil. Not my bailiwick...

Be careful that you actually get a 70 amp, looks like the auto parts store have simplified to 60 amps for everything. Here's a link to O'Reilly's listing for an 83 Turbo and they show 60 amps, with compatibility to other non-turbo cars - http://www.oreillyauto.com/site/c/search/Alternator/01468/C0330.oap?year=1983&make=Nissan&model=280ZX&vi=1209406&keyword=alternator The "special connector" just jumps the wires that need jumping, plus comes with the diode installed correctly to prevent the engine from running when the key is turned off. If you're upgrading a 240 (280s don't need the diode). Pretty convenient and clean looking, not too expensive, plus it's reversible if you've got a classic. Doesn't really look like a rip. http://www.thezstore.com/page/TZS/PROD/12-4067

Error...

Don't forget that there is a resistor in line between the coil neg. (-) and the tach in the stock configuration. Probably to limit current through the coil, I would guess. If you still have the wires in the engine bay you could connect there or find the resistor up by the old ignition unit in the passenger footwell. I would be interested in how accurate the stock tach is compared to the MS RPM reading in the MS software (which I would assume to be accurate since it is essentially all digital). Just curious, if you get a chance to compare (or anyone else that knows).

My comment was mainly for KillerBjt. He asked the question.

The Picasa photo-editing program from Google is free and will let you export pictures to a smaller size. http://picasa.google.com/#utm_campaign=en&utm_source=en-ha-na-us-bk&utm_medium=ha&utm_term=picasa Import the pictures then export them to a smaller size <1000 x <1000. They will still be of high resolution. This is an interesting thread but the pictures are killing me, both loading-time wise and trying to read the text, then shrink the pictures down so I can see them. They might be the biggest pictures I have ever seen on this forum. Just trying to be helpful...

I don't know about the S130 but on the S30 you can see the slave cylinder from the engine bay. With a stretch you can actually reach down and work on it. Follow the hydraulic line. You could at least pop the rubber cover and see if it's full of fluid.

You could put a six tooth reluctor ring on your damper and get the stability of a crank trigger.

Looking for memories from your past... Unlike many here, I am still working with the 30+ year old mechanical distributor. I have a couple of distributors that have numbers on the advance mechanisms that don't match the specs. from the FSM. Am I correct in reading the numbers on these two distributors as 11 and 9.5 degrees of centrifugal advance at the distributor shaft? Which should translate to 22 and 19 degrees at the crankshaft? If so, they must be modified from stock, or there were more varieties from the factory than listed. They are a D6F4-01 (should be 10 [20] degrees, from FSM) from a 1976 280Z and a D6F5-02 from a 1978 (should be 9 [18] from FSM). Both manual transmission. Pictures are attached. Thanks for any insights. Edit - What I'm really wondering is how a 9.5 and an 11 got in to two different 280Z distributors. But any comments about the changes in distributors from year to year would be appreciated.

Look down at the bottom of this link - http://www.datsunstore.com/index.php/cPath/7_634/sort/2a/page/2 They're cheaper than the early models but still spendy. Not terrible though. You should check the specs. though on the 83 vacuum canister and see if that's what you really want. 83 had knock sensors and extra gizmos, valves, etc. on the engine so that they could run lots of vac. advance at certain conditions. I asked ZMan what the specs. were on their replacement canisters (in the link above) but he couldn't say. Stock 83 had up to 30 degrees crankshaft vacuum advance possible (according to the FSM, I'mnot really sure whn it comes in to play though), which is a ton. Were it me, I would try to find a 79 canister, which would be very close to the 75 specs., although there are still many possibilities. They had 5 different distributors for 79, with from 10 to 18 degrees vac. advance possible. The canisters look like they should interchange from at least 74 through 83, but I heard that they won't. Probably worth checking though.

Heat, via flame, on the strut housing works wonders. The cast iron will take a lot with no damage. If you're not replacing the bushings though, be careful not to damage the bushing rubber. If you are replacing the bushings, you can heat it hot enough to soften the rubber, and the center metal and rubber of the bushing might come out with the pin.

The stock tach counts the breaks from the negative terminal of the stock coil. A wire runs from the negative terminal, through a resistor and to the tach. Probably not what you were looking for but might get you started. EDIS will most likely have a different output or outputs for you to use.

The cheapest, simplest, kit-based V-8 Z is probably one with a carbureted Generation I or II small-block chevy engine. JTR has kits and an instruction manual and it has been done many times. http://www.jagsthatrun.com/ The LS series engine swap will be more expensive, especially if you go with fuel injection, although you can get them carbureted also. Engine control for a fuel-injected engine swap will cost more over the carbureted engine. Quite a bit more, if you go for one of the high end EMS's. Plus tuning, etc. By the way, 350 and 400 are common Gen I/II displacements. The LS's are designated in liters, generally, and are also known as Gen III engines. Just an observation from another low-budget guy...

I put some misinformation out here and don't want to steer anyone the wrong way. With the above setup, I did get light pinging at ~2000 rpm, low-load (high vacuum). The combination probably has timing up in the low 40s at those conditions (17 static + 18 vac. + mechanical = too much). I went back to a 1976 vacuum canister (15 degrees of vac advance) and it's still there. I dropped two degrees of static advance and all seems good now. 15 static, 1978 mechanical advance (17 total) specs., 1976 vacuum advance (15 total) specs. Putting this out there for anyone watching, that might still be messing with distributors. I'm stating to see why programmable EMS are so popular now.

The "lttle valve" is a Zerk fitting. It's made to fit the nozzle of a grease gun. Grease guns and Zerk fittings used to be everywhere back before today's age of the sealed bearing. Greasing things used to be part of regular maintenance. If you examine your tie rod ends and ball joints on the front of your car, you will probably find more Zerk fittings under the grease and grime. http://fittingsandadapters.com/greaszerfit.html http://www.sears.com/shc/s/search_10153_12605?viewType=gal&psid=21x65099&viewItems=24&keyword=grease+gun&i_cntr=1292367568232&sid=ISx20070515x00001a

Pretty typical of a dirty/corroded high beam/low beam switch. At the base of the turn signal stalk. I have had luck, twice, with spraying Deoxit DN5 in to the switch itself and working it around. Or you can take it apart and clean it. I have also found the contacts in the headlight switch, on top of the steering column, corroded and loose. It is easier to clean than the high/low switch since it is accessible. You can unbend the metal tabs and pop it apart to get to the contacts. Recrimp the metal tabs down tight to get good pressure on the contacts. Your "no low beams" problem suggests the high/low switch is the issue.

The GM HEI transistor ignition module (look for 1977 Camaro ignition module at the parts stores) is cheaper ($20 +/- range) than the MSD unit or the Crane, but it takes more work to get it installed right. The links describing the connections for a 280Z, and a 240Z with a later electronic ignition are below. Basically, one side of the module hooks up to the pickup coil in the distributor, and the other side connects to the positive and negative terminals of the coil. Grounding is through the mounting hole on the module. One option if you're on a low budget, or your current setup is all buggered up. I installed one on a 76 280Z, using the stock coil and resistor and leaving the wire from the coil resistor negative terminal (which came from the wiring harness) unmodified, to maintain the signal to tach and ECU. No wires cut or spliced, just two jumpers from the coil to the module, and the distributor wires moved over. The original ignition module is just unplugged (as described in a separate writeup from Atlanticz.ca about the E12-80 distributor swap - another option for you guys) and kept installed as a spare. It performs essentially the same as the original module, but it's about 34 years newer. Be careful that you know where all of your wires currently come from and go to as they might have been modified in the last 30+ years. The Zs that run carbs could be wired up completely independently of the wiring harness, for troubleshooting or just better functionality, except for one switched power source (which could even be a switched hot wire from the battery if you wanted to avoid the ignition switch). You would lose your tach signal though, but that could be wired in separately also, using the wiring diagram for your model. 280Z GM HEI - http://www.sonic.net/~kyle/hei.html 240Z GM HEI - http://www.sonic.net/~kyle/ztech.html Nissan E12-80- http://www.atlanticz.ca/zclub/techtips/distributor/index.html

You might have a bad damper or missing Woodruff key (the key that locks the damper to the crank, is it in there?). Apparently the rubber can go bad allowing the outer metal ring and pulley to slip. #2 looks right for cam and crank alignment, both valves closed, piston at TDC. But the notch should be at zero on the timing mark. You can look at the injector or intake runner to see which valves are intake. They are in line with the intake valve with the cam lobe directly above.

When?

My comment was really directed at anyone that discusses detonation, not your comment specifically. I agree completely, all RPM matter because that's what driveablity and overall performance is about. I think a lot of this discussion gets diverted by a focus on peak HP numbers. I've seen some good articles in the past on average power under the curve versus peak numbers, and how that is a more meaningful measure of engine performance, but the forum discussions on high CR always seem to drift back to peak HP. Flat torque curves, part-throttle driveablity, etc, get pushed aside. I think that one of your responses in the past was about increased power across the rpm range, improved driveability, etc. I was hoping to direct things back to that perspective. All I'm hoping for is more detail than "10:1 Cr, 32 total advance" gave X peak HP, or similar from anyone who has actual experience running high CR. More details on driveability, the pros and cons of high CR, did they run a "normal" timing curve or ignition map, and how they are making it work.

I was wondering when this topic would pop up again. One question I've been left with in these discussions is, what are the specifics of the timing and where in the rpm range does the rattling occur, when it does? Since Megasquirt seems to be very popular, maybe a timing v. pressure and rpm map would tell the story. Or the basic distributor specs. if one is used. I ask because I have been mucking around in the area of distributors and timing and ignition modules recently and have found a very large range of possibilities for variation in "stock" timing curves, mechanical and vacuum, from the variety of factory distributors used in the Zs over the years. So every time I see 28 degrees or 36 degrees total, I wonder "when"? When is the timing all in and when does the detonation happen? It seems like, especially with something like Megasquirt, that instead of reducing your total timing if you were on the edge, you could move the curve up the rpm range. Anyway, I think it would add some useful detail to this interesting and recurring topic, and maybe add some clarity too.

Start at about post #20 in this thread and things should make sense - http://forums.hybridz.org/index.php/topic/96568-alternator-question/page__pid__909445__st__20#entry909445