I managed to fix the indicators by replacing the front right indicator/parker lamp assembly, which was badly corroded.
But I also found that the headlamp fuse is running very hot, and had a 20A fuse instead of 15A. I did not find anything burnt under the column cover but I'll take another look at the turn signal switch.
I'll also take a good look at the fusebox and clean the terminals and check resistance on the headlight circuit.
Ok so I seem to have some electrical gremlin(s) in my 120y. Seemed to start after I drove my car through a a fair bit of water. Shallow, but it was for quite a way with a lot of splashing around.
Straight afterwards I noticed that the right hand indicator no longer flashed but stays on. Didn't think much of it at the time. However next time I drove the car I could smell a burning insulation smell. Driving the car home and I think I saw a waft of smoke coming up by the steering column. Pulled over, waited, turned everything off I could (headlights, fan, radio) then nipped home (about 1km). Smell didn't seem to return. Haven't used the car since then.
Everything seems to work except the right indicator. I have the car running now idling for 20 mins (no lights, fan indicators radio etc on) and can't detect anything like a burning smell.
So how to troubleshoot this? I am moderately handy with a multimeter, but have dealt with few electrical issues on the car. Going to start by removing the clamshell / steering column plastic and look for toasty bits. Also check continuity on suspect circuits. I am suspecting something to do with the indicator or lights.
For chin spoilers the Mk1 Golf is popular and works ok with 1200s and B210s. You can search what people have done on this forum. Don't know about B510 spoilers. Yahoo japan auctions is a good place to find interesting 1200 spoilers. They all seem to require a bit of fiddling to fit.
I don't know about rear spoilers although they came out on some of the South African cars (140z/160z) and I understand that they are rubber. Very hard to find I would say but I know someone who did get one.
I've swapped a few grilles around from different years both early, late, JDM, coupe / sedan and while I haven't swapped that particular early coupe grille I'd be quite surprised if it didn't screw in the same way.
That reminds me, there's a nice old couple near that have a shop that repairs automotive instruments. That is all they do and they've had the shop for 50 years. Very interesting to chat to. I brought in my 180km 120y speedo to have the odo reset and they instantly recognised it as a JDM item.
Anyway they have a nice write-up about car clocks on their website
They are around, they tend to be expensive for some reason. They were fitted to the coupes. I have never seen any datsun clock of any kind that works though. I believe it is possible to retrofit a new mechanism.
If you remove the #1 spark plug (the front one!) and put your thumb over the hole you can feel the pressure when its on the compression stroke as it approaches 0 degrees. Be turning the pulley clockwise. Try and advance it a bit say 5 degrees before TDC and set the dizzy up so the rotor lines up with the #1 lead. Start the car and then set the timing from there.
As Datsandy says check the firing order 1342 and remember that's in the counterclockwise direction.