Jeff Berk

Sorry for the delay in getting back to this. I'm working out of town and only have weekends to visit my car. I think the problem may of been resolved or at least I can drive the car for more than 1/2 hour without the ignition failing. It must of been that extra ballast resistor or a high resistance from the taped splice. The car has been working for 7-8 years and only periodically had ignition issues so I'm assuming one or more weak links in the ignition began to fail. Here's the wiring as it stands now. Some of the colors were hard to see until I cleaned the wires off with solvent.

I have a correction to the wiring diagram I provided after I cleaned things up a bit and stripped off some electrical tape. The round connection has 3 wires on the harness side and 4 on the ballast/coil side. I've also found that the BW wire that attaches to the + terminal on the ballast had been cut, then twisted back together and taped. I removed the redundant ballast resistor, and soldered the wire splice so it's making better contact. I'm holding off on the suggestion to disconnect the blue wire since I'm trying to minimize the variables when I make a change. In other words, removing the second ballast resistor and improving the wire splice is enough for now. If the problem persists, I'll disconnect the blue wire. I find it odd that the connector eliminated one of the wires. Note: I have a few blank field books from work lying around that I am finding useful for keeping track of issues and updates to the Z. I wish I thought of this sooner. I also found a source of Brother shrink tube that works in a standard Brother labeler. It's great for labeling wires and holds up better than adhesive labels.

The connector is definitely factory and is shown on the wiring diagram. The blue wire splits with one wire going to another resistor and on to the C-4 connector and the second wire that leads to what's labeled as a "full transistor ignitor unit" (FTIU) (whatever that is). The black with blue wire goes to the C-5 connector The black with white wire goes to the emergency switch, the FTIU and the Inter Lock (sic) switch.

ZH, yes, the Mallory and the pair of resistors were in there 8 years ago when I purchased the car. This issue with the Unilite has been showing up from time to time so maybe I need to get rid of the second resistor. I'm assuming the resistor with the extra connection in the middle is the one I need to keep. I'll report back after this weekend.

I'm unfortunately working out of town for the past few and next few weeks so I have only weekends to address this issue. Mallory wants me next to my car when the give tech support which makes it difficult. Looking at my notes from last weekend I think there is an issue with a ballast resistor once it warms up. If you look at my sketch in a previous post as reference, with the engine running after making sure the Uni-lite drops its voltage to 1.4V when the sensor is blocked, the voltage into the top resistor (R1) is 13V and out of the resistor to ground is 9.5V. The output from R1 goes to the bottom resistor (R2). R2 shows 9.5V in and 5.9V out. After running the car and letting R2 warm up to 120F, the resistance of R2 is 45 ohms. It previously was 1.7 ohms. So if I measured it correctly (the terminals are a bit hard to get a good electrical connection), the resistance of R2 increases as it gets warm which would drop the voltage to the coil. I should of confirmed this but I can do so on Saturday. Could an increase in R2's resistance cause the voltage to drop to the point where it will not permit the ignition, specifically the Uni-lite, to operate?

I just re-ran the voltage drop test and its currently showing around 12 volts with the LED not blocked and I think 1.5 volts when the LED is blocked. I tried driving it around for 20 minutes to force it to fail but all I managed to do is annoy my neighbors by making a lot of noise. Why are there two ballast resistors? I'm assuming that I have a total resistance of 3.0 ohms with the three terminal resistor providing 1.3 ohms and some fraction of that on the middle terminal.

I have a little more information after some testing. These measurements are all with the car cold. The primary terminals on the coil measures 0.5 ohms The positive terminal to the secondary coil wire terminal is 12.8 K ohms I have two ballast resistors that I'm labeling as R1 and R2 in the diagram. The R1 measures 1.3 ohms while R2 measures 1.7 ohms. Resistor 1 has a third terminal that I didn't test.

I'm a couple of hours away from the Z until Saturday so I need to check this list of potential problems this weekend. I was using the following procedure to test the uniLite: chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://documents.holley.com/a605_test.pdf I think the last time it failed with the voltage at 12 V with or without the LED blocked. Once it cooled, the voltage would drop and the car started right up. From an internet search it looks like the Mallory coil should have the following values: primary: 0.6ohms secondary: 11.3kohmf

The brown wire is the ground. The mounting plate is attached by two screws but thermal paste insulates the plate from the distributor. I'm tempted to make a heat shield for it but it hasn't had one for 50 years so why now?

My 260z has a Mallory Unilite distributor, promaster Coil (#29440), and a Mallory Ignition Active Power Filter. Starting this year, when I drive it a short distance the engine just dies. When I go through the Unilite diagnotics, it show the ignition module has failed the test where I measure the voltage between the negative side of the coil and a ground with both the ignition module LED blocked and open. I've tried replacing the ignition module but the problem persists. Mallory's tech suggested a better coil ground so it now has a dedicated ground wire going directly to the battery. I can restart the car after it sits until the engine compartment cools down. The ignition module then reads good. It will run for just a couple of minutes but again shuts down. I don't think the fuel tank is building up a vacuum because opening the cap doesn't result in a rush of air and doing so will not start the car up again. I recently added a new radiator cooling fan to replace a fan that stalls and draws a high current and installed an under engine splash guard so I should be getting better air circulation. I got rid of the dead head fuel system a PO installed and the fuel now flows back to the tank to minimize vapor lock. The fuel pressure gauge shows adequate fuel pressure. Should I try a new coil or power filter?

Thanks for the suggestions. I'm worried about damaging the speedometer cable by pulling on its. I'll give it a try. I might try and find an old speedometer cable and improvise a pulling tool.

I have a slight leak at where the speedometer cable connects to the transmission. I ordered some seals but I'm unable to remove the pinion to install them. I removed the metal tab that holds it in place and can twist it with a lot of effort with a pair of channel locks (without damaging the threads) but only in one direction and it does not move out. I looked at this video but it wasn't too helpful: Can anyone offer a suggestion? Maybe thread something onto the threads and use a slide hammer or something to tap it out?

I don't know what others are using but I installed a pair of marine brakers on the firewall.

I would think plastic film, regardless of material, would be more prone to being scratched than glass. The mohs hardness scale (used to describe hardness of minerals) lists glass as 6.5 out of 10. A steel knife is 5.5. This means that glass can scratch steel but not the other way around. Unfortunately quartz is 7 so if you are at the beach, be carful how you wipe the sand off your windshield. Sorry for the earth science lesson, I'm a retired geologist.

A few months ago, I created a differential cover to go with the KAAZ LSD I installed last year. I finally got around to installing the cover and as fast as I filled it, the gear lube leaked out. I'll pull the cover and see if I can figure out what I did wrong but for now, I'm going back to the original cover for now. I'm guessing there is a problem with the mating surface. I'm not necessarily posting for advise as much as I need to vent. Hopefully my other little projects worked out better so I can get my Z back on the road. Other projects I'm finishing up include a freshly rebuilt 5-speed, oil pan gasket to stop the oil leaks (I hope), DIY engine splash shield, and fabricating plastic inner fender covers.

Those tail lights are very cool.

I've had a dash cover in my cart for about a week in anticipation. Its either going to be installed or used as a form to make a leather dash cover (attempt #2).

I'm answering my own question, I just got a 10% sale announcement from Z Car Depot THIS FRIDAY 11/29 TAKE 10% OFF YOUR ORDER FOR OUR ANNUAL BLACK FRIDAY SALE! DISCOUNT IS AUTOMATICALLY APPLIED AT CHECKOUT

Hey All, Is there anything Z related on sale this week worth looking at? Jeff

This is a long thread so hopefully this hasn't already been addressed. The Japanese battle flag on the inside of the hood... Is that painted on or is it a vinyl film? I wanted to cover my hood's underside with a printed graphic but I'm concerned about heat damage. I know my engine compartment get really hot.

Here's an update. I finally got to an Autocross last weekend to try out the LSD. I was delayed by a brake issue that kept my 260z up on blocks for a few months. The thermistor I installed in the differential drain plug did not show a significant heat buildup during the autocross. The temperature reached about 110F. The interesting part was that during the drive to the event, I drove at 70-80 mph for about 45 minutes. That built up a temperature of 230F. The KAAZ tech warned me that above 200, the oil will begin to break down. I may need to install that finned diff cover which unfortunately means I need to modify some other components to get it to fit.

So far so good... I took the Z out for an autocross event last weekend and the brakes worked and didn't leak. I also talked to my local Z mechanic that I fall back on when I get stuck and he commented that if I'm not driving my car in harsh conditions, I likely didn't even need the boots. He said that his cars with Wilwood brakes don't use them and sure enough, when I looked up Wilwood rebuilding kits, boots are not included.

Would anyone be willing to do a 3D scan of the convex side of one of these? I think I can create a left and right mold from this to try to vacuum form these. Scanning can be easily done using a cell phone with the free version of the KIRI Engine app installed (https://www.kiriengine.app/ ).

The asking price for this part seems very lofty. If I can find one that I can scan or use to make a mold, I think I can churn out a few possibly using a vacuum form method. I've never did a vacuum form (excluding back when I used a toy in the 60's), but I have a unit available nearby.

This was a April 1974 260z so I would of thought that it would of also been on some of the 240z's. If its part No. 63830-N3600 and 63831-N3600, then it looks like you are correct that its a 260/280z part. Maybe that will make it easier to locate. I think the part I'm looking for is 64186-N3600 and 64187-N3600 that is identified as part 80 on the diagram. BTW: I finished my caliper rebuild so after nearly 2 months of waiting on some parts, I can drive this thing for a few weeks before it goes into hibernation.