Mikes Z car

I keep hoping someone will see your thread and share something with you on the likely source of your noise but I would say a likely culprit would be the throwout bearing. If the noise continues I would think pulling the transmission would be in order. I did that on the 71 240Z (build date 8/71) I had 30 years ago not that that means I could do it again without help. When I did it I left the engine in the car. The throwout bearing looks like a small metal doughnut with bearings so one face can turn while the other remains stationary though I am having trouble visualizing a failure mode that would cause what you are hearing. Maybe the bolts have worked loose on the clutch itself?

I am not a member of any local clubs. I looked into them a few years ago though it seemed they were inactive. I am not aware that any of them get together any more. What year is your car?

Meridian, Idaho ???!!?? That is less than 15 miles from me. I'd rather not guess on your noise though. Do you idle with the clutch pedal depressed or do you idle by putting the transmission in neutral and leaving the clutch pedal alone? Does the noise repeat at regular intervals like something is spinning and hitting somethng else?

Nice story. I also believe in karma, would have done the same thing.

I would have loved to have been there. Too bad the net doesn't have some way of doing video meetups, they might be fun.

This picture of a drain hole on the left side of the car was taken with the cowl removed. I think this is my car before I did any anti rust in this area.

Chas, What trash can did you throw your rejects in? Just kidding. What did you make them out of? Mike

tlorber, Your asking for more pictures reminded me that I neglected to mention that I replaced the inner and outer hatch weatherstrip and tail light rubber seals all using Vintage Rubber weather strip products. Their rubber products fit perfectly though the hatch has to be slammed a bit to get it to close due to the inner weather seal (my hatch latch may be bent a bit). No issues at all on the outer hatch weatherstrip or the tail light weatherstrips though I have not done any water leak tests. Also, I made my own carpet using indoor/outdoor carpet. I could not get black carpet at the time so I used gray. The cargo straps came from a 1/1972 parts car. They were stiff until I washed them in hot soapy water. This is a bit heretical but I also added the tool bins my car did not have by installing the tool bin doors from a 1/1972 parts car. When I removed the doors from the donor car I included a one inch strip around the doors including the hinges to insure the doors would function well in their new location. The install works well though my metal working skills leave a little to be desired. Fortunately my lack of skill in that area is hidden under the carpet. I kept the metal I cut out of my car in the outside chance someone would want to weld it back in. The front door panels are from a later model car, I am guessing from a 280Z. The car did not come with the finishers that go around the interior door handle. I have inner door panels from a 1/1972 car but I don't know how similar they are to the panels that came from the factory with my 1/1970 car. They have red cloth on them. The scuff mark on the door in the picture isn't noticeable on the car for some reason. I also replaced the master vac and did the gas tank interior with POR 15 standard tank seal plus painted the outside of the tank with blackshell. Also replaced the filler tube. The brown stain on the right suspension in this picture is from anti corrosion spray that dripped out of the rear frame rail when I sprayed the interior of that rail. (new exhaust pipe too). The vinyl on the shock towers on the front side towards the seats was damaged on my car when i got it. It looked like something heavy had been hauled there. I had some textured vinyl that I cut slightly larger than each hole in the vinyl and worked it into the hole followed up with silicone rubber used as a glue. I don't know if I will ever replace that vinyl or not but in any event it looks a lot better now than it did. Captain Obvious, The Z mechanic here told me they are $400 racing seats that is all I know. He races his 280Z, next time I see him I will ask him if he knows what they are. I remember when I drove my previous 240Z in a spirited fashion around corners I would slide in the seat sideways a bit sometimes. I can't slide with these seats they grip the road to save your life as the old ad for tires used to say.

My 240Z car sat in the garage with the interior finisher panels removed for five years to expose the bare metal so I could work on preventing rust and other prevention and repair. Recently I completed repairing interior panels, cut shock tower vinyl, door panels, things that did not work and spraying anti corrosion material in all the rust prone areas not accessible when the car is together. I wrote blogs on some of the repair to share that. This is how the interior looks today after I put the interior back together. I still have body work to do on the exterior in back under the bumper but that can wait; I want to drive this car. Other exterior work for under fender anti rust may also follow later, maybe new paint too. The picture above looks pretty much like the car did when I got it except I replaced the aftermarket steering wheel with a factory original steering wheel (the later one with holes) and the aftermarket shift knob with one that looks more like the original one did plus new floor mats. My wife passed on a couple of months ago, she bought the shift knob for me for Christmas a few years ago, it will always remind me of her! She came to me in a dream a few days ago. I put in the door sill scuff plates that say DATSUN from a 240Z at the JY. Also the gas gauge, map light, headlight and tail lights, turn signals, windshield wiper, power antenna, clock now work reliably (I added relays for lights for reliability) and the electrical connections in the fuse box and inter harness connectors have been cleaned and/or soldered to make the car reliable. I fixed some carb issues, added a third brake light that flashes, replaced the non working hatch window defroster by adding a "frostfighter" kit, replaced the water pump, added hatch window louvres, replaced the fuel pressure regulator and fixed at least one fuel leak under the hood. I greased the choke cables with spray lithium grease using the process described by Blue (Thanks Blue!) and the choke was so easy to pull the first time I tried it I thought something was broken. It used to be a real struggle to pull the choke on. I like to go sit in the car now and listen to the newly installed radio with the new speakers I put in the back and the door speakers that were already there. I wrapped all the new speaker wires with electrical tape the full length of the car so they look like the wiring already in the car that came from the factory though of course they are hidden alongside the original wiring. I installed earphone type jacks on the back speakers with the jacks sticking out from under the interior finishers for access so I can plug in larger speakers that disconnect the rear car speakers though the speakers I put in the car behind the interior panels surprise me on how good they sound. I have a couple of larger 7" speakers with enclosures plugged in now in the back for better bass sound. It is really pleasant to listen to after listening to the radio speakers in the old DD. #907 is ready for the street!

Fun seatless story Jeff! Thanks for sharing! I drove slowly around the block in my seatless car sitting on a very low foot stool after doing some carb work a few years ago. The seats were out for welding in metal panels on the floor for some rusted out holes and for putting rust bullet on the floor after the welding work. I just put both seats back in permanently a few weeks ago. With the seats out I slowly went past a neighbor and explained that I had no seat and that was why it looked like I was sitting on the floor. He seemed amused at the whole thing. I was cautious not to do any jackrabbit starts sitting on a footstool, figured I would fall over backward if I did. Seatbelts were pulled out too.

Someone correct me if any of this is wrong but 14 gauge is commonly used in house lighting circuits and is usually protected with a 15A fuse. 12 gauge house wiring for wall sockets is protected with 20A fuses. But in automotive applications they would fuse those same wires with larger fuses. Maybe fire is more of a problem in a house because it kills people but if a fire starts in a car you just hop out and run off? The gauge VS fuse size issue was discussed on another thread a while back. Does anyone have a chart showing what gauge wires in a car are protected with what size fuses? I THINK 16 gauge wire in the early Z car is protected with 20A fuses. The 40A fusible link at the starter in the early Z protects a 12 gauge wire right? All this rambling would seem to indicate a 12 gauge wire would be needed for the short wires to the 40A fuse.

When I lived in California I used "guaranteed to pass" which sometimes seemed to help. I never knew what was in the stuff (and never tried to drink it).

The diodes can short on the alternator. The diode pack can be replaced but I don't know if that is often done nor if you have to take the alternator apart to replace them.

What I read is that a fusible link can briefly withstand a greater short circuit than a fuse can. If true then a maxi fuse might blow prematurely compared to the protection offered by a fusible link. But, new cars don't use fusible links, they use fuses right? My own car (240Z) has a hard to find large glass cylinder 40A fuse in place of the fusible link, no problem so far but I have had no short circuits. If my battery goes dead and the 60A alternator in the car tries to push 60A charge current through that 40A fuse I might be looking to find a replacement fuse. I would want to keep melting wire from a fusible link burning out off of anything but what material would offer that high temperature protection that you could buy? A fiberglass sleeve? Cooper makes fusible links that are a tin alloy and another kind that is a silver alloy but I didn't see any indication they use them in automotive applications, just in load centers.

Tomo, One thing I read yesterday is that you can pull on the ends of a burned out fusible link and it will stretch like a rubber band. beermanpete, Thank you for the information.

Thank you for the idea. Seems like it would work with the holes. For now until I paint the car I just put a tiny piece of aluminum tape with adhesive backing over the holes to keep out water. I remembered that I did that on a hole in the siding of a house once and it was still there when i moved out.

There might be a transistor amplifier that drives the tach needle that might not be well stabilized against temperature variations. All I know about that is that one way for the designer to temperature stabilize a transistor amplifier is to put a resistor in series with the emitter of the transistor and ground. Maybe the designer selected the wrong resistor value or the resistor has changed in value with time, I have seen them change in old radio equipment. I wouldn't know what else to guess though.

They are supposed to be 4 AWG sizes smaller than the wire they protect per Wikipedia at https://en.wikipedia.org/wiki/Fusible_link An electrical fusible link is a type of electrical fuse that is constructed simply with a short piece of wire typically four American wire gauge sizes smaller than the wire that is being protected. For example, an AWG 16 fusible link might be used to protect AWG 12 wiring. Electrical fusible links are common in high-current automotive applications. The wire in an electrical fusible link is encased in high-temperature fire-resistant insulation to reduce hazards when the wire melts. I wonder if the wire you have is flexible because it is a smaller gauge or because it is made out of some alloy?

The pictures look good. Back in the old days I bought a pair of fiberglass fenders from JC Whitney. They didn't fit well enough for me to make them look good with the body work skills I had back then so I sent them back. That would have been around 1978.

I thought I looked at how the links are made and there was insulation made of fiberglass (in addition to the wire insulation?) with the idea that it won't melt at high temperature keeping any melting metal from a burning out link from falling on anything and starting a fire. Then there was the idea that the link is one gauge smaller than the wire it was protecting, but maybe a non standard smaller gauge? It might be that the insulation is pierced to insure that all of copper conductor part of the link is fully encapsulated with the fiberglass insulation. If you take one apart please post pictures I am curious about how they make the links. I wonder if a caliper could be used to verify the gauge of the link wire though that might be tricky if the link is stranded, don't know.

You are making perfect sense to me. I just wish I had an answer for you and hope someone else does as I am curious about this. GM has a one wire alternator, not sure how they wire that to get around resistances.

If that happens to me I will try the easy approach first and just try the swearing. Then in desperation if that doesn't work I will try the hammering.

The pictures are helpful. Since it is an intermittent issue the approach I would use would be to improve the existing grounds meaning the C4 connector ground and the battery to body ground strap. I am not sure what car model you have but I have seen on a 240Z a ground wire that connects to a ring that looks like a washer that goes under the mounting screw on the cigarette lighter which I guess could be the C4 ground showing in your diagram if your car is wired like a 240Z. That ring could be taken off and scraped clean (The area under the ring could be scraped too) and the screw mounting it tightened. I like to solder any connections I have any doubt about such as the crimp connection on that ring. My car has two ground wires that connect to the battery negative (ground) terminal. The very large one goes to the starter ground and then there is a much smaller one that is screwed to the car body next to the battery on the firewall. On my car this wire that is screwed to the firewall continues on and ends in a ring that goes under a screw on the engine block but I don't know if the wire that goes to the engine block is a stock arrangement. This smaller wire could have the firewall screw removed and the body and screw scraped clean, same thing for any connection to the engine. I am out of ideas, hope some part of this helps. Someone else might want to chime in.

My wild arse theory is that the ground for those gauges is loose. That would explain the intermittent aspect and I think why some gauges go up and others go down when the ground opens up and stops grounding. Any dissenting opinions or ideas of where the ground is? Finding the ground point for the gauges would head in a good direction if this theory is correct.

Won't load for me right now either. It did a couple days ago when I did that earlier post. Well on my car a PO managed to damage the vinyl covering on the rear shock towers. Something heavy and hard must have been hauled in that area as many repairs had to be done. Different people have different ideas about what is okay to do to a car.