Zed Head

Might be this aftermarket part - http://www.blackdragonauto.com/icatalog/zr/full.aspx?Page=41 88-702

Hope I didn't kill your thread Datsunlover. Any luck?

I browsed the FSM (slow Saturday night :disappoin) and it looks like the Floor Temperature Sensor relay is powered up when you hit Start. The light is supposed to go on at Start and go off when On, unless the floor is hot. It's in the Emission section. It's possible that you just have a low battery or bad battery connections. The relay buzzes because you don't have enough juice to activate it completely, therefore not enough juice to Start the engine. Like Ford starter relays. Buzzz, buzzz, buzzz, crap, battery's low...

According to page EC-9 of the FSM, if there is no power to the switch then vacuum is actuated. The valve closes when energized, opens when no power. Odds are that whoever put the 5 speed in just disconnected the switch, so you probably have full-time vacuum advance if nothing else was messed with and things still work. Really though, you should just put a timing light on your engine and check/set the initial value. Then while you're hooked up, rev the engine with the vacuum advance hose disconnected (plug it to keep things running smoothly) to check mechanical action. Then temporarily connect the vacuum advance to a manifold vacuum source at idle to see if it advances. The small port for the heater controls would work fine for that. That would get you started to see if things are even working. If you wanted go further you could measure how much advance you get with an adjustable timing light (I think they call it a dial-back timing light) or adding some timing marks on the pulley. Once you get in there with a timing light you'll figure out what's working right and what's not. Its just a big guessing game if you don't measure.

Z Tyler, I just remembered something about the 1976 Z that you should consider - the manual transmission model, as delivered from the factory, only uses vacuum advance in 4th gear. There is a switch on the transmission that closes in 4th, which activates a solenoid valve on the engine, allowing vacuum to get to the vacuum advance. The engineers designed the engine to run without vacuum advance in all gears except 4th. So your problems are most likely not due just to vacuum advance problems, if your engine is still in stock form. Don't forget it came with a ported vacuum source also, which can confuse things if you're checking it at idle.

It could be timing issues. It sounds like it might be retarded. Check your vacuum advance. Read this thread (coincidentally recent and same year car), post #3 by Beandip, about checking your vacuum advance mechanism. http://www.classiczcars.com/forums/showthread.php?t=38890 Check your mechanical advance to make sure it is working. If it is stuck you'll have retarded timing at higher rpm, which will hurt gas mileage. In general, the engine will be more responsive and get better mileage with properly advanced timing. A bad water temperature sensor or connection will cause the engine to run rich all of the time. A far-out possibility for the inconsistent idle - there is an electronic advance for 1976 non-CA models, that kicks in when the engine is cold then turns off when hot. It adds about 6 degrees of advance when cold. I don't know if this will cause a 700 rpm swing but it will cause some. It is controlled by a temperature switch on the thermostat housing.

When you slide the drive shaft out of the transmission, the gear oil will come out unless you have drained it first or have the rear end of the car jacked up. You might want to make sure that you can get the transmission fill plug out to add more before you start. I had the same problem with the diff fill and drain plugs. If you heat the area around the plugs with a propane or MAPP torch you should be able to get them loose. The diff gets pretty hot when in use so the heat shouldn't hurt it. I could not get either to budge until I applied the torch.

Back on topic (yippee)... Maybe this old quote applies (had to Google it to get it right) - "In theory, there is no difference between theory and practice. But, in practice, there is." Jan La Van De Snepscheut (apparently a Cal Tech computer expert) So it doesn't really do much. The Datsun engineers put some effort in to it though. Too bad we don't have those old reminisces from the engineers that worked on it, like we do for some other car makers so we could know what they were thinking at the time.

I read your original post. Here's a summary: The car ran with starting fluid through the intake when you got it. Then you "set the motor to TDC". Did some more stuff. Now it won't run at all. It sounds like you just think that you set the #1 to TDC and/or set the distributor wrong. Any way to go back to before you did anything? You must have had the timing good enough to run in the beginning.

If the car starts but then dies, it could be the fuel pump safety cutoff. On the 78 I believe it is controlled through an oil pressure switch. The switch has to see oil pressure to close the contact to run the fuel pump. Typically (at least for 76 with the AFM switch) the car will start, run for ~3-5 seconds, then die. Not sure why warmer would be better than cold, but it is something to look at. If this is the problem, then hitting Start real quick as it is dying, will get it to run a few more seconds again (because Start bypasses the switch), although you will get a grind from the starter gears. I had this problem on my 76 which has the AFM controlled fuel pump switch.

Don't bite mel marabante. They're just words on an internet page from some anonymous Benny Hill fan... Not worth the effort.

Doesn't the coil ground through the tachometer circuit? Just a guess, no real knowledge of what you're doing. But I did see that you have the tachomoter output disconnected, although I'm not sure what effect that would have with your setup..

I did not know that. I have a 280. Thanks for the quick correction. I think that the L terminal on a newer alternator still needs 12 volts, low amps, to power the windings immediately. It could be checked with a volt meter, with the key on, to verify. That's where I would start if I had this problem. If the L terminal is not getting power, then you can focus on the wiring. If the L terminal is getting power, focus on the alternator itself. I'll stop now...

I'm sure that Zs-ondabrain can explain in depth, but, as I understand the charging system, the L wire does what the "cut-in" speed is doing. I believe that it magnetizes the windings right away so that the alternator can start generating current immediately. The L wire runs through the red charging light (Lamp) on your volt or ammeter. If the red light comes on when you turn the key on, and the other end of the wire is connected to the L terminal, then the windings are getting powered as they should. It goes off when the current starts flowing. Does your red charging light work as it should. Lighted when the key is On, off when the engine starts? I could be iffy on the details, but I'm sure that the red charging light is an integral part of the system and needs to be functional and wired correctly for the system to work as designed.

Actually, you missed my point (no pun intended). I do stand corrected though that the L20B came in carbed form in 1978 in the US. It has been a good discussion. Overall, I learned something and if I ever a get a carbed Datsun I will be ahead.

This has turned in to an interesting technical discussion (aside from all of the extra stuff). Here is a paragraph from the 1972 FSM, in the Emissions section (page EC-13), but it seems to be a general statement that the coolant lines are there for consistency in fuel supply, by keeping the gasoline at a constant temperature through heating of the carburetors. I could not find a comparable page in the 1973 FSM. Draw your own conclusions.

Your page is for a 1978 EFI engine. The discussion is about coolant lines on a 1973 carburated engine. Replay point...

I came across an interesting discussion on this topic over on Hybridz a while ago (link below). Apparently the keyway is mainly for initial indexing, not holding the damper/pulley from rotating out of sync with the crank. The force locking the damper/pulley to the crank comes from the compressive force of the bolt on the crank end. So minor damage to the keyway should not necessitate crank replacement or even repair, if you can live with the knowledge that slot is not straight anymore. Not perfect but might save you some time and money. It's worth a read. Post #21 summarizes pretty well. http://forums.hybridz.org/index.php?/topic/91212-cracked-crank-pulley-worn-woodruff-keys-crank/page__st__20__p__872134__hl__crank%20keyway__fromsearch__1entry872134

I hope you're not looking at the volt meter in the dash. Mine was off by several volts, as I've heard many are. You should measure voltage at the battery with the engine at about 2500 rpm according to the FSM. The FSM for 1976 says 14.3 - 15.3 volts at 68 degrees F. It also recommends measuring amps but the procedure is a little more involved. You still haven't really stated the problem. Does the battery go dead or does it just not charge? Could be different causes...

So the problem is that the battery does not charge correctly? The old-style mechanical regulators are adjustable. Have you measured the voltage at the terminals with the engine at ~1500 - 2000 rpm, to see what the regulator is doing? Need more numbers to make better guesses...

Maybe the can of Seafoam was rattling when you revved the motor. I have actually spent a few moments in the past wondering what "that noise" was from the rear end of the car then realized it was the old beat up speakers behind the seats sliding back and forth...

Click through the choices in the link. You will get to a page that shows a positive and a negative option for the style and size chosen. I second (third, fourth?) the thanks for putting this out there. Much better than what is typically found in the auto parts store.

Never mind. Not a good discussion starter...

Didn't mean to stir things up with my KISS comment. The last S can be inflammatory and that was unintended. So Rocket88, you have options. Since you mentioned that the coolant was flowing along the head/block interface, you should make sure that you look closely at the thermostat housing. It might be starting there, flowing down to the interface, and just showing up between plugs 1 and 2. It's difficult to see up under there, a mirror might help. There are several sensors in the housing that could leak plus the housing gasket itself. Have fun.