Zed Head

Overheating usually leads to compounding of interacting problems. Excess heat causes excess piston expansion leading to localized heat in the bores and more expansion. The aluminum pistons usually bind up in the bores before things get too too hot. Motorcycles seize all the time from over-heating. I've never seen any discussion of rings losing temper due to overheating. I have seen discussion of crankshaft bearings losing lubrication due to oil-thinning though. Seems like certain engines have certain failure points. As far as block problems due to being aluminum, you really need to know if the bores are sleeved or not. The old Chevy Vegas were known for ruining blocks due to over-heating, but they were still saved by sleeving the bores and rebuilding. I'd find a Hyundai forum to get the details on that engine. But like dj says, the evidence is probably on the cylinder walls.

I have a can of the CRC spray-on material. Goes on red. Sticky. Only worked for a short while, on two different brands of pad, one unknown, the other Beck Arnley. (Sprayed on the back, Iv'e never heard of any treatment for the face of the pad). The Beck-Arnley pads were nice pads. Had a good feel, better than the Posi-Quiets. Dirty though, Still squealed, even with their stick-on shims. Maybe there's something in the water here. Regardless, the factory steel (clean steel, no polymers) hanging shims work great. Not a peep, from backing out of the driveway to all manner of stopping conditions. Just tried the Posi-Quiet system 'cause their ad copy said it would work, and they run cleaner. I'll probably go back to Beck Arnley in the future.

It's interesting that the guy seems to have built a few engines but doesn't seem to be well-known. I've never heard of the shop. Cylinder pressure will give some idea of potential ping problems. That's probably in the future though.

I think that the adjustment holes are for taking up wear. 1 = new parts 2 = worn parts 3 = very worn parts

Forgot to say, I notice that the tape on the top of the engine says "Do not turn over". Does that mean don't turn the engine crankshaft or don't turn the crate? Also see that the camshaft lobs have some wear so it's not a newly ground shaft. Zinc may not be as critical.

More support that a free-flowing exhaust system can have a big affect. You asked about the drop off after 5500. That seems to be typical of the L6 engine, unmodified factory issue. If I understand what I've read in the past, head work and cam profile are needed to extend the range. My stock L28 isn't worth taking over 5000 RPM before shifting to the next gear. You can see your torque dropping dramatically there in the dyno plot. It would be interesting to know what kind of head porting Ritalon did, and if they installed bigger valves. And read up on zinc for the cam break-in. It would be a shame to have break-in problems.

That fuse must have been defective or of poor design or both. A proper fuse of that design typically fails with absolutely no drama. Most people don't even realize it's blown unless they inspect it closely. No smoke, smell, heat, or burn marks. Just a missing filament. And many amps through a dead short will melt the wire insulation. You'll get smoke and smell then. I would check the wire on the back of the fuse box that attach to that fuse terminal. It's probably melty looking. Follow it up in to the harness and you might find the short. It's probably waiting for the right bump.

VR is short for voltage regulator. 14.5 volts is good, using a good meter. The dash gauge is isn't very good. I only asked because it was undefined. One man's "way over" is 16 volts, anothers is 14.5 I'm a numbers guy.

Here's a source. It will probably look like the one he has though. http://www.zcarsource.com/engine-harness-240z-260z-280z-280zx-300zx_8_56708.html

The fuse is supposed to melt when it gets hot. The only explanation for getting that hot at the fuse connection is that you had high resistance there, creating a hot spot. A balance between the local hot spot and heat dissipation that allowed the cover to melt before the part of the fuse that was supposed to melt melted. In short, dirty/loose fuse contacts. Common on the 240Z's, I believe, not so much on the 280Z's. I'd clean them all up. Weird that you have multiple problems happening at once. As noted, the headlights and the tail lights are two different circuits. I went back and did see this though - "I was still showing way over 12V on the dash volt gage". How way? Could be that the excess heat was caused by excess voltage, and excess amps. Maybe your VR is going bad.

A simple shorted tail light bulb socket could blow the fuse. I had one of those. But the fuse destruction and high heat under the cover shouldn't have happened. Have you had the fuse box assembly out? Maybe you shorted some wires behind the that fuse. You said it happened all of a sudden. Implying that something moved and shorted while you were driving. I would check all of the things that you've worked on recently. I didn't catch where you wired in your fans and relays.

On sale at Amazon! 2/3 off! Might be worth it just for the six hose nipples. http://www.amazon.com/Mr-Gasket-9706-Universal-Clearview/dp/B00068OR8M

Two completely opposite experiences. Fascinating.

The headlights are on a separate fusible link. Maybe it came loose. Not sure what else is on the circuit. The dash lights on my car will go off when the tail light fuse blows. Same circuit. So if you don't have dash lights, you may not have tail lights either.

This is with no separate hanging shims? That's the question at hand. Any pad will work and not squeal if you use the factory shims.

Probably doesn't help, but the factory harness looked like it's been hacked and patched when it was new. They used a lot of crimps and "tap" junctions. Then buried them in insulating tape. Even if he gets a replacement harness he'll still have to do some meter work to get power where it needs to go. He might be in the same boat with a new harness as he is now with his old one. Just saying...

Coolant is conductive. If you sprayed it all over the engine's electrical parts you might have some new electrical problems.

Yes, the anti-rattle pieces are installed. Odd that they call them anti-rattle if they're actually anti-squeal. It's not a question of pad quality, it's how to keep them from squealing. Are you running any of the pads you mentioned, without added shims and without any squealing at all, cold or hot?

The first thing you should do is to stop thinking in terms like "all that crap". Better to understand what the parts do and how they work so that when they're gone you'll also understand why the engine runs differently. The factory timing specs. were set to meet emissions standards. Since you're not worried about that any more just set the timing to where the engine runs the way you like it to run. The specification is irrelevant now. You're on your own.

Did the engine get wet from the coolant that came from the radiator? Did you jostle any wires when you were changing the radiator? Or the hoses? Running good when cold, then bad when warm is a sign of a disconnected coolant temperature sensor. Check that first, maybe you'll be lucky. Make sure you didn't swap it with the thermotime switch. Download the Fuel Injection Guide and run the tests at the ECU connector if you don't find an easy fix.

Another thought that popped in to my head - the pressure inside the tank might contribute to the gassy smell by pushing fumes or liquid through any small leaks in the filler neck, in to the cabin. But the tank's outlet and return lines will see the same pressure. So it won't affect fuel pressure, since fuel pressure is between the pump and the regulator. Doubtful that you would have over 28-36 psi of tank pressure under the cap since that would blow the tank up like a balloon. Just saying, don't get distracted by the odd things. There's a spring-loaded relief valve in the vent line that holds a small amount of pressure before venting. And a valve in the cap to let air in if pressure goes negative. So, the gas heats up, pressure builds, the gas cools down, the cap lets it reload. Also, on fuel pressure - a clogged filter could lower flow and pressure. Another simple fix, but only need to look at it if the measured pressure is low.

Didn't mean to demean with the above post. But many many people have been here trying to solve their EFI problems and they always end up taking the measurements that need to be taken. There are so many interconnected pieces, and often someone will adjust one to try to help the problem (like your timing adjustment), and end up hiding the true cause. Volt/ohm meter, fuel pressure gauge, and timing light and you can get the engine to where it should run right. You might find something off on the way.

Some people say that a little bit of pressure is normal on the newer 280Z's, like yours. You're focusing on the simple obvious stuff though. Noises and smells. They won't tell you enough to solve the problem

Considering all, it really shouldn't be dying if it's the lean AFM problem. I've had that issue and the engine will sit and idle forever, and drive with the intake popping, but it doesn't sputter and die. It just won't accelerate. Even seven years ago the car was 30 years old. Could have a rusty tank, or even old fuel if you haven't been ablt to drive it enough to cycle through a tank. You need to confirm that you have good consistent fuel pressure. It's critical to the EFI system operation. Build the basic information, like fuel pressure, correct timing, intact cam lobes, notch - groove - timing mark aligned, etc. It might even be an ignition module problem. What does the tachometer do while it's popping and sputtering? It gets its signal from the coil, and gives clues about what's happening there. Gotta measure and record those basics though. Get them all in one place for a good review.

Have you had the valve cover off? Inspect the cam lobs and verify that the notch and groove match the zero mark on the pulley. When you can't find the simple solution you need to go back to the basics.