gone2long

Hi Matt, Sorry, but I am in the boonies. Can get virtually nothing here, and spending a couple of grand to go to Japan for spark plugs aint exactly in the cards. Do you know of a Bosch plug that would cross over? The FR8DPX was suggested, and the specs for heat, reach, gap, etc. are the same as the NGK, BPRES - 11 suggested in my truck manual. The FR is a "platinum plus" plug with "Super plus technology" - whatever that means. : ) Sounds like a Bosch plug upgrade, though relatively expensive, might be a good idea. Comments anyone? PS - Yeah, I found that video too while trying to decide on a plug substitute. Good stuff. Thanks, G2L

Greetings from SE Asia, I was having starting problems with my 1979 1/2 Datsun 720, so I decided to change the plugs. Locals advised against using NGK plugs saying that many on the market here are actually counterfeit. Instead, they suggested using Bosch plugs, at $6 a clip here. Anybody know which Bosch plug I should ask for? I should also mention that the small (1,800 cc?) Z engine on her has been modified to do away with the original emissions system, so she uses only 4 plugs. Thanks, G2L.

Hah! Yeah, you know the math, did occur to me. : ) The highest rate at low ideal was 14.5, even closer to half our AC number. Guess I won't worry about it as long as she keeps running strong. Thanks again, G2L

Thanks Mike, Today, I brought the alternator to a shop and mentioned the AC current of 27 volts, but they didn't know what to make of it. We opened up the alternator and one of the diodes was burnt. We replaced the entire rectifier bridge and that seemed to fix the charging problem as I was able to get 14.33 + readings at low idle with no utilities on. Also, thankfully, the warning light went out. I did an AC test on the battery just for the heck of it, and to my surprise I was now getting 30V of AC current at the battery. Really have no idea what to make of that. The electrician's comment was, "it doesn't matter". Whaddaya think ? G2L

Wanted to "bench check" the alternator, but looked all over town and couldn't find anyone who could do it.

Yeah, thought about the regulator as a possible problem, but did another test today, and it seems like the diodes are shot. See my new post "27 Volts AC Current Across the Battery Terminals ..." for details. Thanks, G2L

Here we go again, Truck is a 4x4, 1976.5, 720 Datsun with a Z18 engine in it. Alternator light has been dim and recently worse ever since I had it rebuilt about 1 1/2 years ago - new diodes, some wiring, but no rewind. Asked the shop why the dim red light was still on after they supposedly "fixed" the alternator, but they just shrugged. Never paid much attention to it because the truck ran ok and the battery never failed. Had some other wiring issues and got them fixed about 6 months ago with a complete rewiring, but the generator light seemed to get "redder" over time. Did some checks recently and got contrary results. But today, the battery still showed 12.65 volts cold. It dropped to 12.43 at idle, but at a fast rev (guessing about 2,500-3000 rpms) she stayed consistently between 14.1 - 14.35. Still wondered about the red light so I did a "diode test" that i found on the internet. I kept the engine on idle and set my multimeter to AC current. Then I probed the pos and neg terminals of the battery with my pos and neg multimeter probes. Low and behold, the meter showed 27 VOLTS OF AC CURRENT coming through the battery. Apparently, this means the diodes are shot, no? Interestingly, just out of curiosity, I shut the engine and did the same test, getting the exact same result. Should that have happened? If so, why, and is it indicative of any deeper problem or just some kind of residual charge? Thanks, as always, for your comments and suggestions, G2L

Truck is a 1979.5, 720 with a recently repaired (1 1/2 years prior) alternator. Used a digital multimeter to do some checks on my alternator output at the battery and got conflicting readings on different days, so I would like to check the alternator output at the alternator. Can anyone tell me an easy way to do that? Found something on the internet about that, but would like to hear from you folks. Thanks, G2L

Understood. Thanks. Hoping that my high speed, highway test will help rule out anything other than the resonator, and hoping there is nothing else to worry about at least for the moment. G2L

The latest muffler shop guy didn't need to point it out. I already knew basically what was under there, which was done originally in a previous muffler shop, about three years ago. Hadn't looked at if for a while, so didn't remember exactly what solution was in place til I had her up on rails again recently. Like being diagnosed with cancer or having a heart attack, deciding where your vehicle breaks down is not usually a matter of choice, as I am sure we all realize : ) In this part of the woods, if she breaks down within 20 miles of some hut that might be called a muffler shop, chances are that, if the word "hanger" were actually understood, the next one of any make might be 200 miles and two islands away, in the closest big city. That was the situation I was in when we originally used the rebar option. Probably be a good idea to find somebody somewhere who could put it all back the right way, using whatever hangers might be available, but like the old Navy saying goes, "If it works, don't fix it", and redoing the way the exhaust is hung is not an immediate concern in that I am sure that the rebar connections are not causing the rattle. They are welded on tight. What do you think of the muffler shop guy's analysis, that the resonator caused the vibrating sound? In any case, we will find out about that soon as I will take her on a 100 mile freeway test drive tomorrow. Will let you guys know what I find out. Thanks for your note, G2L

Latest Update: Went to the muffler shop. Guy rattled the exhaust pipe, muffler, and resonator. With the truck running, he found leaks in the resonator weld, and starting tapping it. His analysis was that it was shot, and all the interior had essentially decayed and that we needed to replace it. We cut it out and tapped some more. It sounded very hollow and was kind of light, so he took that as a verification that it was shot. Nothing rattled around when I shook it, however. Put on a new, home-made one, which was a little heavier and did not make a hollow sound. Sounds fine when idling or running at low speed. Have yet to test it in 5th running at high speed and coming off the throttle or engaging clutch, but I explained those symptoms to him, and he seemed convinced that the resonator being shot was causing them. Comments anyone? Think he knows what he's talking about? Will report back after I test her at high speed on the highway. BTW, there are no rubber connectors holding the exhaust system in place. Could not find the parts, so the exhaust is Oki-rigged onto the frame using welded rebar. Not a great solution of course, but the only one available at the time. The vibration from the road and years of use/rust probably caused the resonator welds to leak, so it was probably a good idea to replace it anyway. I'm pretty sure it is the original, dating back to 1979.5. The latest work cost a total of $23 (Philippine peso equivalent) including the new resonator and the labor. Can't complain at that price. That's it for now. Thanks for all the great advice - G2L

Hmmm, i seem to remember the nipple on the cable end, but I don't remember seeing the clip. Could the clip have popped off after hitting a bump, thus causing the cable to disconnect and the speedometer no longer functioning? The plastic is very old and probably very brittle from engine heat and years of tropical sunlight beating down on the dash and hood.

Thanks Mike and Lockleaf for the tips. Have not gone back to the muffler shop yet, but when I do, I'll have another look at the motor mounts as well. Could very well be the root of the problem, 'cause, as mentioned earlier, I know that one of them is loose. Will report back on what I find. Thanks again, G2L

BTW, when I had a problem with the speedometer, going up to 40k and stopping there, a local mechanic pulled the gauge cluster and told me that the speedometer cable was "broken". Well, the cable was not broken, but it was disconnected from the cluster assembly. Is it possible to "break" the cable connection when removing or trying to re-connect the gauge cluster? The Nico club procedure detailed how tricky it was to re-connect the speedometer cable due to the limited space available to do so. Maybe the mechanic who pulled the gauge cluster was not able to reconnect the speedometer cable when he tried to reinstall the cluster, so he simply told me that the cable was "broken". Sorry, but this is the kind of crazy shit I have to deal with out here in Asia. Whaddaya think?