meestapeta

So I changed the gearbox oil tonight. I refilled it with Castrol Hypoy C, which apparently is the uprated version of Castrol Hypoy, which is what was recommended in the repair manual I have. Interestingly enough, I found 5 or so 1/2 inch long strips of metal stuck to the magnet on the plug, along with plenty of metallic dust. Refilled it, let it off the jack so it could drain to the right level, and then put it back up and capped it. Now it shifts smoother and doesn't buzz in 3rd gear anymore. Yay! I'll probably do the diff in the next few days.

That might be it. I always just take the cables off, sand the pickups or clean them with a wire brush, and then put them back on good and tight. If your wires look bad stripping them like that would probably be good, too. Also, if you don't have a battery bracket your battery could be slipping around and pulling the connections loose. That used to happen to me too, but I just bought a strap to put around the battery, not the expensive battery bracket getup, and its been doing fine.

Thanks for the advice. I definitely have not been hearing knocking then. Too bad now the mid grade is up to $2 a gallon.

So what kind of gearbox oil is the best? I think the manual recommends Castrol GTX or something, is that stuff any good? I'll avoid the Redline after hearing that story.

Hey folks, thanks in advance for any advice. So I realized the other day that the oil in my gearbox (78 280Z 5 speed) probably hasn't ever been changed. Right now its at about 127k total mileage and it shifts fine, actually quite well for such an old car, but I was just wondering about that oil. Is it complicated to change it? Expensive? Is it worth it? And have any of you changed it and noticed an improvement in shifting quality?

Check the cables that connect directly to the battery. I used to have problems because they would jiggle loose or cut out altogether. Does it ever read full voltage with the key in and then click when you try to start and then read much lower voltage?

So I've just finished up my first full tank of mid grade and it's been running fine. Actually, I even got better gas mileage, 20.5 instead of 20 mpg. But that might have been other factors, because it's pretty small. Anyway, just trying to keep the post current. Anybody have any thoughts?

I've got a 78 280Z, stock except for a K&N air filter, and the other day I noticed that premium (91 or 93 octane depending on the gas station) gas is getting to be almost $2 a gallon. So I thought I'd try the mid grade stuff, 89. I had maybe 1.5 gallons of premium left in there and added about 6 gallons of 89. The engine's been running fine and I haven't heard any knocking, but I was wondering... Is it easy to distinguish knocking from the valve and timing chain noise of early Zs? The descriptions I've heard of knocking are a clickety noise on acceleration, which my car has always made. Just want to make sure I'm not doing engine damage to save a couple of bucks.

I just installed a new fan clutch and the noise is gone. The engine revs a little easier than before, too. Thanks to everyone for all of the help.

Has anyone here successfully installed a junkyard or generic (read: cheap) electric fan on a Z? I have a '78 280Z and I am looking at the $130 electric kit for sale through motorsport auto, but I am also looking at just replacing the fan clutch or possibly getting an electric fan from somewhere else. Does anyone know how to do this or where I could find out about it?

Spinning the fan right now will either cause the belt to slip in one direction or turn over the crankshaft and cause the car to move in the other direction. The fan will not rotate at all relative to the water pump housing. How is the fan clutch supposed to work? Because right now if I rev it to 3000-4000 the fan starts to blow really hard. PS: I like your 240 setup, Brett. That must be a really fun car.

I know it's not the K&N, I've had that on for about 6 months, and it did change the engine noise, but this new noise is louder and different from that. I did read about fan clutch problems, as far as I know my fan runs all of the time, hot or cold, high or low revs, as long as the engine is on. Ok I just checked the fan and it is difficult to turn with the car off, but it does move. Also, while the fan was removed to replace the water pump I messed with it and it seemed to loosen up a little, because I know it was turning freely when I first reassembled the car. Perhaps driving it seized it back up and that's why the noise came back after a few miles. How do you test the fan clutch?

Hi, I have a '78 280Z with the stock L28 engine. The only modification to it is a K&N filter and large diameter intake tube. Anyway, my problem is, a while ago I started hearing a whooshing noise when I revved the car. It doesn't matter if it is in gear or not, and it gets louder the more revs I give it. It comes from the front of the car, near the fan. I have read that the water pumps on Zs can be weak, and everything else seemed to be in order up there, so I tried replacing that, along with the fan belt for good measure. I put it all together and drove it today and went a few miles running fine, but then the noise came back. The car runs at temp with fine oil pressure, and power doesn't seem to be affected. But the noise can't be good. Does anyone know how I can fix it?