Captain Obvious

Wow. Those are some nice looking front end parts! I got two other comments: First, there have been reports of snapping T/C rods when using poly bushings on both sides. Now I don't know if your aftermarket rods are stronger than the stock rods (probably are), but you might want to look into that before using poly on both sides. Second, You used a force gauge to check the preload on the steering rack? Seriously?

Well the biggest bummer right now is that if the problem spontaneously went away, you can be sure that it will spontaneously come back again. Are you double dog sure it doesn't have anything to do with the electrical work you just did? You were messing around up front near the parking lights with the fan install. I know it's unlikely, but just seems too coincidental.

Well duh. Who doesn't!!?

Well that's a bummer. So looking at that fuse and the cover, here's my forensic analysis of the whole situation... (Warning... Heresay and theory alert) You have (or had) a dead short somewhere in your parking light system. That dead short occurred spontaneously as you were driving. Hit a bump? Something maybe that had been very close to shorting for some time finally picked last night to be the time when it went the rest of the way? Or maybe it's related to the electrical work that you have been doing recently? That spontaneous dead short blew the fuse so violently that you ended up with arcing sparking inside the glass tube along with ionized air and metal mist from the vaporized fuse material. That ionized air and metal mist allowed an arc to form (just like welding) and that arc not only allows current to continue to flow, but it also produces mucho heat. Certainly enough heat to crack the glass and melt the fuse block plastic. So, you've got this dead short in your parking light system and a fuse that is still passing huge current even though the metal strip is long gone. You're pulling many amps through the dead short, and because of that, your headlights go dim (which looks to you from the driver's seat like they went out completely). Then after some period of time, the arc finally stopped. Maybe the fuse metal burned back so far that the arc could no longer be sustained. Maybe when you flipped the headlight switch back and forth a couple times, you were able to break the arc? Maybe whatever shorted in the first place became spontaneously unshorted? Maybe the high current melted and opened a wire somewhere? In any event, the high current draw stopped, your headlights were able to come back to better brightness, and everything else, other than the parking lights, went back to normal. And for those of you who are wondering "OK, so if this is all true, then why didn't a fusible link blow?" Well here's why... For whatever reason, in Datsun's infinite wisdom, there are a bunch of circuits that hang directly off the alternator with no fusible links between the alternator and said circuits. They are a direct connect to the alternator, and in the case of a hard fault, are happy to suck down as much current as the alternator is willing to produce. I don't know if this is a design oversight, or on purpose for some reason, but that's the case, and yes... The parking light system is one of these "non-link protected" circuits. So, my first question is... Is the short still present, or did it fix itself as mysteriously as it occurred? You can't simply check with an Ohmmeter because all the bulb filiments will make it look like a short to ground (even though it might not be). I would put a new fuse in that spot (like a 5A fuse?) and turn the parking lights on while you watch that fuse at the same time. if the parking lights come on like normal, then you've unfortunately got a continued mystery. If that fuse goes up like a flash bulb, then you need to start disconnecting things until you find out why.

The 78 fusible link for the headlights does headlights only. Nothing else is on that circuit. What's the state of the issues now? Is everything back to normal, or are there still lights that aren't working?

Dennis, That would be such a fine site to see. Thanks for the tip. I'll be sure to do that if I ever make that journey!

So do either of the two restored service stations pump gas or work on cars, or are they both just tourist stops now?

Ignore the dents in the dash and focus on the rest of the car. Pretend the previous owner did it.

That's cool. If I had more time and more money, I'd do all sorts of expensive time consuming stuff, and one of them would be to drive the whole Route 66 from one end to the other.

I'll let you know in a week or so. A local Z buddy of mine recently ordered a bunch of those thinking they might look good. They'll be here shortly and when they get here, we'll try them out to see what they look like. As for a name? No idea. That technology is moving so fast and furious right now that I don't think there are standards to describe them. Other than the BA9S base, I don't think there's anything to describe them other than "oversize" or not.

Yup. That's exactly what would happen. The incandescents will always dim just fine, but the fewer of them you have remaining in the system, the less you'll get the LEDs to dim. And by the way.... As far as the dimming function goes, the stuff like the brake indicator, turn signal indicators, high beam indicators... None of those are connected to the dimmer so they don't matter one way or the other. Leaving them as incandescents won't help your LEDs dim. Only the incandescents that are dimmed will matter. On the 78, the only things that are dimmed (besides the gauges themselves) are the hazard switch, the HVAC faceplate, the original radio bezel, and the A/T shifter bezel (if you've got an automatic). So if you've got a manual trans 78 with an aftermarket radio and have already updated the HVAC bezel, then you've only got one tiny dimmed incandescent lamp remaining in your system and that's the one in your hazard switch.

I don't get over to Hybrid much, but I did see the thread a while ago. I gotta say that I'm more than a little impressed. That's some nice work on such a huge undertaking.

Haha! Glad to help. So my previous owner removed my cargo straps completely and I've been looking for options. I did pick up a pair of old straps off a junker a while ago, but they are very faded. Supposed to be black, but they're a pale blue/gray. I like the ratcheting ability of your mod too. Nice work.

Wow. Very nice. So you're "Captain Overkill"? So you've got access to all sorts of machinery to cut that prototype head, and the only thing you can find to finish off your brackets was freehand on a belt sander?

Cool. So far. so good. I suspect that as you increase the number of LEDs in the system (and reduce the number of incandescents) your "range of dimming" will decrease. You'll always still be able to get full bright, but the "dimmest" lower end will move up. And with that in mind, I think I would concentrate on LEDs that are dimmer rather than brighter. Everyone selling LEDs seems to advertise how BRIGHT they are and all the customers seem to think that the brighter, the better. I've done a little bench testing with a few LED bulbs in spare gauges and I've come to the conclusion that you don't need much. Now, I also know that how much brightness you want from the dash is different for everyone, but I'm not looking for way brighter than stock. I want white, not necessarily a whole lot brighter. YMMV.

The problem is the huge disparity of currents between LED's and incandescents. If you make the pot large enough that the LED's will get completely dim, then your incandescents will all go completely dark in the first ten percent of rotation travel of the pot. And if you make the pot small enough that you get reasonably good control over your incandescents, your LED's won't ever get completely dark. I think the best solution is to use all one technology or the other and not try to mix the two. And if you DO have to mix the two, a PWM dimmer would do a much better job of handling the two differing technologies because it's a duty cycle based control instead of a resistance based current limit. I think that if you do switch everything over to LED's, a 400 Ohm pot would be a good place to start. You could use traditional fixed value resistors first though just to test the brightness and then once you're confident on the upper end, buy the pot. But be warned... I expect you're going to run into the same problem with the pot shaft being too short and will need some sort of extend like what I did for the PWM module I made.

It's the one that points toward the radiator. Vacuum from that front port should "T" to go to two places. 1) the distributor vacuum, and 2) the carbon canister control line. I think I've got a spare throttle body in the shop. I'll snap a pic or two and label the connections when I get a chance.

And while we're on the subject... I'm no bulb expert, but I did do a little digging recently as a result of some of the stuff I'm doing to my car and here's a little bit of "Bulb Theory 101" that I picked up along the way: The "BA9S" simply describes the BASE size and shape. It does nothing to describe the glass shape. For example: "BA9S" - Means "Bayonet base which is 9mm in diameter and has a single filament." Bulbs with a BA9S base can come in one of many different envelope shapes: G = "Globe" - These are spherical (like a globe) T = "Tubular" - These are usually longer than they are wide. S = "Straight" - These are supposed to have straight sides, although they often do not...? In catalogs, the envelope shape letter is followed by a number, and that number is diameter if the glass envelope measured in eighths of an inch. Yeah, I know... I didn't make up the nomenclature. So, for example, you'll see bulbs listed as "G3-1/2" or "T3-1/4". What that means is: "G3-1/2" - Means "Globe (spherical) bulb with a globe diameter of 3.5 eighths in diameter or about .4375 in diameter" "T3-1/4" - Means "Tubular shaped bulb with a globe diameter of 3.25 eighths in diameter or about .406 diameter" I did a bunch of digging into the original bulbs (Toshiba A12V3.4) and I've come to the conclusion that they are not available on the free market. They are a BA9S base, but the glass portion measures about .310 (8mm) diameter. Using the modern nomenclature, this would be a "G2-1/2" and I've not found that size anywhere. Might be completely ubiquitous on the other side of the planet, but not here. I've not checked if the larger G3-1/2 bulbs will fit through the hole in the back of the gauges, but I have confirmed that the small T3-1/4 bulbs fit fine. In other words: "A bulb with a BA9S base and a T3-1/4 envelope fits in the dash gauges." Sorry you started the discussion?

I've found the easiest way to change those little bulbs is to: 1) Put on a rubber glove on hand because the rubber provides better friction to the glass globe. 2) Pull back on the center wire a little to compress the spring inside the socket. 3) Once you're not fighting the spring anymore, turn the bulb with your gloved fingers. Once you get the hang of it, it's really pretty easy. Don't try to push the bulb in to compress the spring and try to turn it at the same time. It's much easier to compress the spring with the other hand. Works great for insertion as well as removal.

And one other thought about leaving an incandescent in the system. I suspect the people who have replaced their dash gauge bulbs with LED lighting have done just that... Either by accident, or on purpose, I suspect they have left a bulb or two (or more) as incandescents. Depending on year and options, some possible culprits include: HAZARD switch, cigarette lighter, HVAC faceplate, A/T shifter bezel, original radio. If you got a 260 with an auto trans, you could leave FIVE incandescents in the system and still have LED's in all your gauges.

I was asking about mods like a headlight relay upgrade because if you would have done that mod, you would probably have an unused wire going through the grommet on the passenger side that could have been re-purposed for your fan override. Independent of your fan controls though. Yes, I would recommend a headlight relay upgrade. The original switching system is overtaxed by the headlight current and I'm continually surprised they didn't use relays in the original design. They used a relay for the fricken horns, but they didn't use any for the headlights??? You've got a 78 right? Already has an internally regulated alternator.... Just musing ideas.

Kurbycar, Yes, LED's can be dimmed just fine using a regular potentiometer, but there's a catch... The catch is that the potentiometer must be of an appropriate value sized for the current going through it, and the stock dimmer pot is not of appropriate value for LED's. Goes like this... The stock dimmer pot is adjustable from 0 to 10 Ohms. When it's cranked to 0 ohms, you get full brightness. No problem. Problem comes into play when you crank to full dim... You're putting a 10 Ohm resistor in series with the LED (or LED's if it's a bulk string) and they could care less. The LED's draw so little current that there's very little voltage dropped across the 10 Ohm pot and the LED's still light up at near full brightness. If you include one incandescent bulb somewhere (or a low value resistor instead) wired in parallel with the LED's, that one incandescent bulb will provide a low impedance path around the LED's and allow significantly more current to pass through the 10 Ohm pot. The additional current through the pot will increase the voltage drop across it and the LED's will have less voltage to work with. You probably still won't get full brightness range, but at least you'll get more range than you would without the bulb. If you really want full brightness range, you need to switch to a higher pot value (probably on the order of a couple hundred Ohms) or switch to a PWM type dimmer. http://www.classiczcars.com/topic/52446-pulse-width-modulated-pwm-dimmer-control-upgrade/

I think there are only two electrical grommets that go through the bulkhead wall. The big one on the driver's side (for the EFI) and the big one on the passenger side (for everything else). I'll take a look at the wiring diagram and see if I can come up with any bright ideas on a wire you could repurpose. This is for a wire that goes hot when you hit your override switch, right? Connects to green on your control relay? You done any other mods like a headlight relay upgrade?

T-handle looks great, but somehow the thought of grabbing ahold of two pounds of sub-zero stainless steel on a frigid Canadian winter morning just doesn't do it for me. Sounds too much like a tongue on the flagpole. To each his own though. I certainly owe you! I can cut them a tiny bit tight and you can lap to perfect fit? Shoot me a PM.