Zmanco

I'm attaching a zip file with a bunch of info from when I thought I'd try to repair my 73 tach. There's schematic included. In the end I couldn't find a convenient source for the germanium transistors so decided it would be easier to swap to a later 280z voltage triggered tach, and indeed it was. I don't work in the semiconductor industry any more, but perhaps someone who does could find a source, or an alternate part number. But unless you're obsessed with keeping everything "original" (in which case I doubt you'd be spending much time on this site!) it's far easier to swap in the later 280z tach. Just use the mechanism and keep your old face and needle and it will still look stock. Tach repair.zip

"Ooo Ooo, make it go away!" And is anyone else bothered by how the defender's left leg is bent? Mine hurts just looking at it.

Hmmm, interesting question. It seems to me that injecting water upstream of the turbo to improve the maximum flow of the turbo makes sense - but this would only matter if the turbo was undersized for your target power levels. For example, if you were trying to push a stock 280zx T3 turbo into the 300+ HP range, then I could see a benefit to injecting upstream of the turbo. If the turbo already has enough capacity, ie. for a given pressure ratio (PR) and flow, it's still within a reasonable level of efficiency as shown on the map, then I would think that practical considerations would favor spraying after the turbo. For example, even with higher water pump pressures, all else being equal, spraying into a warmer air flow would probably result in more complete vaporization and subsequent reductions in temperature. So I think you have to take into account how well the turbo fits the application before you can determine which approach is best.

I don't know anything about Gary's but Arizona Z Car and Palnet both used to offer spacers.

Before I did my L28 turbo swap I briefly looked at used LS1 + T56 options. Most were in the $4k range depending on mileage. I've read others buying totaled Camaros/Firebirds and parting out what was salvagable to recoup some of the expense. I didn't see a clear way (without getting lucky) to get a decent package for $2k so stayed with the L28.

The Mr. Gasket pump is spec'd for 4-7 psi which is high for SUs, although I know a guy locally who is running it with no problems. Years ago I replaced mine with this: Airtex 110-E8016S It was trouble free with SUs, and also triple webers. I'm still using it to feed a surge tank for my turbo engine so it clearly has plenty of flow.

Now you're making it personal. I'm done here.

Take a look at buying rebuilt calipers at O'Reilly or Autozone or the like. When I did my upgrade the cost that way was barely more than buying cores at the JY and rebuilding them. Shop around - you may be surprised at the difference in prices for parts like these. Here's a good tutorial on proportioning valves: StopTech There have been some excellent discussions on this site too. Try searching on "proportioning" or "prop valve".

Now and then a skydiver's parachute fails to open and they still live. Does that mean that skydivers don't need to use parachutes? A single case doesn't prove a point. Two answers: 1) I never said that discs weren't better than drums when designing a system from scratch as is the case with modern cars. But that's not what we have here. In this case we have an existing car that was designed and optimized for drums in the rear. 2) With the advent of traction control and VDC the brakes can be used for purposes besides stopping the car and hence can find themselves asked to dissipate even more heat. Discs do that better than drums. The stock brake system when in good condition has enough braking force to lock all 4 wheels. It also has enough heat dissipation capability to stop the car from freeway speeds without fade at least once. So the benefits of upgrading are to be able to make repeated stops without fade and the corresponding longer stopping distances. Changing the brake equipment will almost certainly affect how much braking force is generated for a given amount of brake pedal pressure. Given that the stock system is well balanced between front and back (I'm sure the Nissan engineers spent some considerable time to obtain this), changing the brake equipment at only one end is bound to upset that balance. Adding bigger brakes in front will likely cause the fronts to lock even sooner than the rears, thus lengthening the stopping distance. This is not an improvement. Changing the rears from drum to disc will either result in more or less braking force for a given brake pedal force. If it's more, then it's possible the rears will lock first. A spin is likely if this happens. If it's less, then the rears are actually doing less work than the drums were and the stopping distance will be longer. Again, this is not an improvement. I do think that many people who upgrade start with stock systems in poor condition and hence attribute the improvement to the upgrade when in fact they would have achieved the same thing, maybe even better, by rebuilding the stock system and changing to higher temp pads and fluid. FWIW, when I first bought my Z 7 years ago I remember reading a post by either JohnC or Jon M saying essentially the same thing I am here. I went ahead anyway and did the toyota 4x4 caliper upgrade keeping the solid discs. On the street things were about the same (I never measured stopping distance so don't know if I made it worse or not), and on the track they faded a little less, mostly due to the extra thermal mass of the larger calipers I suspect. It was a lot easier to lock the fronts though so my stopping distances grew longer. I've since upgraded to vented rotors in front and discs in the rear and an adjustable proportioning valve and the improvement on the track is huge. But on the street, I doubt I stop any shorter. Given the OP said he was only interested in street driving, I think he could have spent the money and time on some other aspect of the car for more benefit. One last thing: we all have our cars because in the end, they are supposed to make us happy. If changing to discs in the rear helps, then go for it - just do it safely.

That's a factory SU. If you follow an imaginary line straight through the black knob on top to where it would come out under the carb, that's where you'll find the mixture adjusting nut. It's large, around 1" across or so. The FSM is adequate, but it sounds like you might be better off with the ZTherapy video. It's got lots of shots of the carbs off the car so you can more easily visualize it. They also give you step by step instructions. Plus Bruce and Steve are very helpful. I think Bruce hangs out mostly at classiczcars.com.

Just a heads up: the wastegate and actuator from the factory T3 and Garrett T3/4OE are NOT interchangeable, although they are really close. So you'd need to make sure you get it with a WG and its own actuator. Also, the stock factory downpipe won't bolt to the T3/T4's wastegate, and neither will the MSA downpipe. Ask me how I know this I don't know if this is the case with the knock offs... And as was said above, you do need a spacer and longer studs for the turbine to clear the manifold.

If it never read properly I would lean towards a wiring issue, especially since you have a V8 swap. If the input lead to the tach sees a constant +12V I would imagine it would peg the tach at 8k (although I haven't tested this). This could happen if it was connected to the wrong side of the coil. But if it really does occasionally read the correct RPM for a short while, then it sounds more like the tach is the culprit. Of course, I am assuming that all the wiring is solid and there are no intermittent connections. I would start by looking over all the wiring, especially what was changed for the engine swap. If you can find a known-good tach to swap, you'll narrow things down quickly.

Bo, are you using the pads that Ross supplied for the rears? I believe they are some type of carbon-kevlar material, but don't know what brand. Good to hear that you had enough rear brake so you could set the proper balance with the prop valve. For purely street use, especially if you're leaving the rest of the system stock, there's really no functional benefit to swapping the rears to discs. But they do look good I would expect the drums to be more mechanically efficient that discs so if you just replace them with discs and leave the stock prop valve in, I suspect you'll still lock the fronts first. But I'll also guess that you'll be getting LESS rear brake contribution than with stock drums, so the net is that you'll likely INCREASE stopping distances. You should find a safe place to experiment with hard stops to find out how things have changed. [soapbox] You really should study up on how brake systems work, especially proportioning valves. If you don't plan out the system and optimize it, you will likely either 1) INCREASE the stopping distances, or 2) get TOO MUCH rear brake and cause the car to SWAP ENDS in a panic stop. Either way you have made your car less safe. There is a ton of good discussions on these topics here as well as on a few manufacturer sites (Stoptech IIRC has a good discussion on how prop valves work). Just bolting parts on without a plan or taking the time to optimize them rarely improves things. Engineering is almost always harder than that. [/soapbox]

I'm running the equivalent of 6 ohms per injector. After reading up on the injector driver I no longer thinks it's part of it. It dissipates less than 1 W at a full 14A! I'm pretty anal about wiring as I hate intermittent issues like this. But the symptoms on this one are temperature dependent. It only happened on the track where the engine is obviously turning higher revs and sees greater load, it only happened on the later warmer runs, it only happened after several laps, and it stopped as soon as I began driving in a normal fashion, such as on the cool down lap. At this point I think it's caused by the coil driver overheating due to the combination of: 1) Blaster II coil with lower than stock resistance 2) I put a little bit more thermal paste on than I think I should have 3) the transistor next to it on the heat sink controls the IAC and I recently changed a setting on MS that basically leaves that valve open all the time. That means that transistor is adding heat to the heat sink right next to the coil driver. 4) there is no ventilation in the MS enclosure which is mounted under the passenger seat which further reduces any airflow over the case. Rather than chase this further, I've decided to swap to EDIS. I knew I was eventually going to go that route, so now is as good of a time as any Derek's kit is already on its way and I'm off to the JY on Saturday.

I went that route because the rotors are a little larger diameter which should in theory (all else being equal which it never is) allow more braking torque. You can always reduce it in the rear via the proportioning valve, but you can't increase it. You didn't say what the rest of your plans are, but given you're going with the stock fronts for at least a while, make sure you install a proportioning valve.

I've played around with a few, but wouldn't recommend any for the track yet. My next set (when these are worn) will likely be Porterfield R4S in the front and R4 in the rear. The R4s probably won't do much on the street when cold, but I only drive it for fun when it's nice weather, so am not worried. I did mine before kits were popular. I sourced the brackets and SS lines from Ross, but found everything else locally for a lot less, especially when factoring in shipping heavy calipers and rotors from Canada.

I've had the Modern Motorsports brackets and 240sx calipers on my 73 for a few years now and have been very happy with them. There is one big "but": I also did the toyota 4x4 vented caliper swap and even with the proportioning valve all the way open, the fronts lock first. This means that the rears are not being used to their potential. I've since swapped to a rear pad with a different coefficient of friction and that made it better. If you go this route, be prepared to experiment with different pad materials to get the most out of the upgrade. You didn't say what you're running for front brakes. If they're stock, this might not be an issue.

Look on the Megasquirt site - that's where I found it when I did it.

If you can, that's better. As I said above, my fuel pumps are powered off the relay board which is mounted next to the MS under the passenger seat. I suppose I could have mounted a remote relay closer to the pumps, but this was good enough. There are no black and white rules - just best practices. Follow them as well as you can, but don't go crazy unless there's a really good reason.

I'm not sure what you mean by "big signal device". I used the term "small signal" earlier to refer to things like the O2 sensor where the output voltage needs to be measured precisely in the mV range. Things like motors (eFans) that pull tens of amps at 14V can generate electrical noise that can be on the order of many mV, so it's best to wire them separately when possible so the O2 signal doesn't get "drowned out" by the other noise.

No need to pull the dash. The tach is held by 2 wing nuts up under the dash on it's back. It's a bear to see them but if you lie on your back and feel around you should be able to find them. One of mine was very tight so I had to get a small pliers up there to break it loose. And don't forget to remove the dash lights (they just pull out). Once loose, you can just pull the tach out towards you while sitting in the driver's seat.

Thanks everyone, there are some clever ideas for mounting that I would not have thought to consider. Paul: that's a great thread and I now see it's a sticky. I had looked in the ignition forum but didn't think to look in the Megasquirt so missed it. Xnke: thanks for the heads-up on the tach. Turns out I swapped to a voltage-triggered tach a while ago because 3 current triggered tachs in a row were wildly inaccurate. Vantage: very clever to mount the coil pack where the dizzy used to be. Any chance you have a close up picture of that? I'd much rather continue to use my existing Magnecor wires instead of buying new.

I'm considering converting to EDIS and would like to see how others have done it. Please post pictures that show where and how you mounted things. Also, if you remember, let us know what the donor vehicle was. Thanks in advance!

Fuel Injectors are another high current device to pay attention to, but it can be hard to route those wires away from the sensors. If you use a PWM Idle Air Control Valve, that's another one to be careful with. In my case I routed them with everything else and haven't had problems, but if you can run them away from the sensors that's better.

If you are mounting the relay board in the engine compartment then by all means, try using the FIDLE relay for the fan. In my case I didn't like the idea of either cutting a big hole in the firewall to fit the DB37 connector through, or just building it up in the car. So I mounted the MS and Relay board under the passenger seat and ran the wires individually through the firewall. Hence it made no sense to run the heavy gauge wire all that way, and to have it side by side with low voltage sensors and possibly induce noise in them.