Lachlan's 1972 Datsun 1200 Sedan

[datzenmike]

Signal cancelling is done at the turn signal. If one side not working look there, something is broken. If the steering column is not exactly centered, (very doubtful) then the signal might cancel sooner on one side than the other when turn is finished and steering wheel centered is all. Take the clam shell and steering wheel off and watch the mechanism and how it works on the good side and compare to the opposite.   

 

If steering wheel is not centered with wheels straight ahead, remove steering wheel and center it on the splines on the column.

[datsunfreak]

On 10/22/2025 at 3:53 AM, Lachlan said:

The indicator / turn signal stalk doesn't self cancel when straightening up after a left turn. It does after a right turn or if going from a left signalled turn to a normal right turn. Given this is operated off the steering column and is not adjustable by itself, it would suggest that the steering column isn't in the centred position

 

That is not how this should work. There should be two pins in the back side of the steering wheel. These are what kick the turn signal off after you turn. If the wheel is crooked one way, it's very likely that one way will cancel and one way won't. 

 

 

On 10/22/2025 at 7:57 AM, datzenmike said:

Take the clam shell and steering wheel off and watch the mechanism and how it works on the good side and compare to the opposite.   

 

You can do this, but I would suggest taking the wheel off and checking those pins I mentioned, and/or seeing if the (often brittle) plastic arm on the switch that interacts with those pins is broken. 

Edited October 23, 2025 by datsunfreak

[Lachlan]

I'm still here! Wow, almost 6 months have passed. I check in most weeks but haven't posted an update.

 

I still have the plucky little 1200 and it's running great. So good in fact, it hasn't broken down once while both our other 'reliable' cars from 2013 and 1999 have had their issues. I get a kick out of taking the old girl to regular life stuff instead of just car meets. I usually get a wave or two and a story from the older generation.

 

Here's what's going well:

 

- It starts strong on full choke and settles into a steady fast idle on about 1/3 choke. Cold engine driveability is surprisingly good. That said, we had a hot summer this year so the real test is about to come.

- The steering and front wheel alignment are straight and true. I ended up making minor adjustments to the tie rods and that fixed it.

- The oil consumption has improved with much less visible smoke. It doesn't like slow moving traffic as I saw puffs just off idle after about 10 minutes of slow driving.

- External oil leaks are largely dealt with and the engine has stayed looking clean.

 

These still need attention:

 

- I haven't investigated the turn signal cancelling function.

- The exhaust system could be replaced in the future. It's a bit drone-y at freeway speeds and it rattles in the hanger at the rear. I think at one point in it's life the muffler separated from the central pipe as there's some pretty booger welds down there. The muffler is also angled weirdly.

 

Normally I use premium 98 octane fuel (93/94 in US), but I tried regular 91 octane (87 in US) on a whim to test an internet theory. The first tank went fine. There was no performance penalty and it might've even driven better. The real surprise was the fuel economy was better on regular than premium. I was not expecting that. For example, I get 8.9 L/100km or 26.4 MPG on premium. That first tank got me 7.9 L/100km or 29.8 MPG. Solid result.

 

However, the second tank came with issues. I still can't pinpoint what the cause was but the car drove as if it was starved of fuel. It was leaning out everywhere. I had to drive home with the choke partially on just to enrich it enough to leave from a standstill. I couldn't drive at full freeway speeds as it couldn't get enough fuel. I parked it when I got home and left it a couple weeks. When I came back for another drive, the problem had gone. It came back in a lesser way a week or two later, then never returned. I drained the fuel tank and it didn't look like it was full of junk. Because of that experience, I went back to 98 and haven't had an issue. With the current fuel shortages, 91 runs out first and 98 is usually available, so I'll likely just stick with it until things settle down and I can try my experiment again.

 

In related news, I have acquired another project. You can read about it here:

 

https://p15-d24.com/topic/63565-lachlans-1938-chrysler-royal-c-18-sedan/

 

I've had pressure applied by my lovely wife to sell the little Datsun, but I'm really having trouble bringing myself to do it. It brings a smile to my face and a sense of satisfaction every time I drive it, especially when it's to run an errand to fix one of the other modern/reliable/safe/better cars. I guess those Datsun engineers really knew what they were doing.

[datzenmike]

Octane is a level of resistance to ignition, it's harder to ignite on it's own specially from heat of compression. It does not increase or decrease the energy contained in your fuel. With higher octane you can run your timing closer to perfect and extract the most power, increasing your engine's efficiency. If running higher octane you might try increasing the timing slightly. 

 

Less smoke may be the rings were somewhat plugged with deposits and driving with fresh oil has loosened and flushed these deposits away letting the oil rings do their job. I'm running Rotella T4, a high ZDDP level oil which is intended for a diesel. Diesel oils have a much higher detergent level and will clean your engine more than the crappy oil they make today. Just maintaining a proper oil change interval would explain the rings cleaning up.

 

The apparent lean running could just be a random blockage of the primary jet. I've had water in the tank get to the carburetor and part block the fuel getting through. Water is heavier than fuel and will sit on the bottom of the float chamber. A little gas line anti freeze will absorb the water. If that's it.

 

Keep on keeping on.