Zed Head

A thermostat that's stuck open will behave this way. Coolant flow isn't controlled so overcooling happens at freeway speeds. But it wouldn't cause temperature to go high. Not enough air flow would though. So a stuck open thermostat and poor air flow kind of fits the symptoms. The thermostat STOPS flow it doesn't cause it. The thermostat is there to increase engine temperature. People get that backward often. So the signs actually show that the thermostat might not be working properly. If the head gasket is bad it will typically overpressurize the system, from leaking exhaust gases, causing fluid loss. If it's an air flow issue, opening the hood typically has an effect. Here's something that I don't think was mentioned - is your heater core bypassed? That can cause overheating by lowering the coolant flow through the block and head.

There was a guy a few years ago who put a P90 on dished pistons just so that he could sell the car. We told him about the CR but he did it anyway. Still wondering who ended up with that car.

2-4-6 Blue brings up a good point about the head gasket and the timing. Could be that you really have a blown head gasket causing your problems.

I'd go with a shroud also. If the car is lowered and/or has an air dam in front the fan might not be pulling air through the radiator, just spinning it around behind it. Nissan built those shrouds for cars with AC because the fans can only move so much air without them. You might also go back to a stock radiator. Your engine is mild and doesn't really need what you have. I have an OReilly cheapo radiator and a shroud and I have zero cooling problems even on the hottest days. By the way, N47 is a stock 77-78 280Z head, not ZX Turbo. You have a plain old 77-78 NA engine at this point. Should be easy to cool.

It's not really a "pig tail", it's a length of wire that comes from the connector by the fuse box. It could either run down the door under the carpet and across to the switch, or across the dash and through the console to the switch. But it will be just a wire in a bundle of other wires. C-6 is in the junction block by the fuse panel. Here's a link to the factory FSM. Body Electrical chapter, Meters and Gauges has the diagrams. http://www.classiczcars.com/files/category/13-280z/

Yes, it does. Is there a problem? Not really clear why there's a question, no offense. Edit - looks like there's a fuse...

I changed my vote. Much depends on how fast the meter reacts, and how well damped the needle is, among other things. I overlooked the basic "changed something and it got better" description. That's the major clue, I think.

That's a pretty good clue except for "fluctuation". Can't tell if it's banging off the stops or jiittering 1 mm around the center. If it definitely got better when you tightened the belt, I'd tighten the belt again and see if it gets better again. I just made a comment based on average behavior but if your belt is oiled up or glazed maybe it is the cause. No matter what though, it sounds like you need a new belt. Get rid of that weakness and you'll know if it's the problem or not. "it is worn and now slipping all the time." The ammeter just shows charging or discharging, and rate of each. So, adding numbers from the gauge to the description would help a lot. And if the battery is fully charged or partially charged. That will affect how much the belt slips. So, just letting the battery drain down will make the problem worse.

Have a torch handy to heat up the casting. Mine wouldn't budge unless it was hot. When it cooled it stopped budging too.

Not clear that you put a nut on that eyelet and tightened it. Is that picture a representation, or your actual alternator? Where's the picture of the adapter plugged in? A loose belt usually just makes noise. I would disagree that it causes erratic charging. (Edit - changing my vote to Maybe).

The wiring will melt before the relay. The VR sensors can generate high voltage at high RPM, so sparking to a ground point might be a concern. But heat from current is probably not since there's essentially no current flow. Look at the connection terminal for the distributor wires, on the fenderwell, and you'll see that the wires are small gauge but the terminals are well separated and kept dry. Might be focused on the wrong thing.

Any loose container in the back will fly around the cabin in an accident. Hope you're not driving the car with a loose container of stuff back there.

It's the way the number 6 looks. 240Z and 280Z just look cooler than 260Z. Imagine if GM had produced a Z26 Camaro. Just not the same as Z28.

If it's that close you might try some of that cooling spray that people use for other problems. Or just a bag of ice on the spindle. I wouldn't go too crazy on using a temperature mismatch though because you don't want it stuck permanently. Or you could use a heat gun on the bearing. Don't get it too hot and the heat gun should let it come back off also. Heat will expand a hole pretty dramatically, I'd bet it will slide on pretty easily with not much heat. But if there's an auto parts store close by you could just go get another set. The next set will be probably be on the big side of the manufacturing tolerance range.

Did the original hood fit right? Why are you replacing it? Did the original hood have work done to it, like body filler or bending? Looks more like your body doesn't fit the hood.

I just went out and stuck a tape measure in to mine and I can get the end to hook on the groove right where the groove should be to match the axle groove. You have a weird puzzle there. Edit - I see your diff picture in Post #1. An R200. I don't think it's a VLSD either because those have two sets of splines on one side, where the viscous coupling unit is.

When my 76 module was going bad the tachometer would show about 50% more RPM than actual. I'd guess this might trigger the injectors 50% more as a result. Just a thought on why the flooding might be happening. I didn't notice flooding on mine, but mine would only fail after about 3000 RPM, then it would keep working but with a bunch of extra sparks. Keep an eye on the tachometer while test-driving. It's typical for them to fail, then start working again after a cool-down. We have several threads about replacing the OE module with a GM HEI module, and a nice writeup in the Downloads area.. 1978 is good for it since there's only one electronic pickup in the distributor and circuit in the module. It's a cheap fix, almost worth doing just as a test and to be ready for eventual failure.

My point was that if the engine is turning over and the key is still on then you should still see the tachometer showing RPM. It's a spark counter. If the tach goes to zero and the engine is still rotating because the car is moving and it's in gear, then there's no spark. In short, if you're driving down the road and the the engine loses power with the tach going immediately to zero then you probably have either an ignition module problem or an ignition system power problem.

Here the back of an R200. That rectangular chunk of metal under the drain hole is how I ID them. The R180 doesn't have it.

Not the greatest picture but you can see the clip hanging in the grove, and that there is only about 1/8 to 1/4" of splne after the groove. And no holes n the center piece. Also a good picture of an R200. Take a picture of the back of your diff and post it.

I got some pictures, which I'll add to the next post. But, in looking at your diff I wonder if it's not an R180 that's made for bolt in half-shafts. Those holes might be threaded and made for bolts.

I have an open diff sitting out that I can pull the axles from and get some pictures. Might take a little while though.

Maybe you don't have a Nissan CLSD. I can't remember if the VLSD has the grooves in the same spot as the other diffs. I know that it has a longer axle but don't remember where the grooves are. What do your measurements show?

Was the transmission still in gear and the engine still turning over while the tach was at zero? Could be that you have an ignition module problem.

The groove in the diff is a slot in the splines. I found when I was messing around with diffs and clips that the clips could be deformed and made too small or too big to work right. They're not spring steel, they're just a bent metal wire. Try expanding the clips, permanent deformation, outside the diff, then compressing them just enough to get them in to place in the internal groove. You might have over-squeezed them when you installed them, so that they're too small to stay in the grooves.