12 hours ago, Captain Obvious said:

Oh, and a couple other details about the carbs... Are you running stock needles? Stock springs?

Yes, I believe I am running stock needles and springs. I h ave never replaced them since Ztherapy redid them

Yes pretty confident I've sealed all the leaks.

11 hours ago, Zed Head said:

Sorry for the rant. I worry about being surrounded by people on their phones asking them what to think.

Here's an example of how detailed experience gets distilled down to something by "AI". You can see the pieces that remain, like unchewed kernels of corn or chewed gum, in the AI response.

This guy Keith Williams seems well known in Datsun world. Why not just read his original material? It seems more informative than what the "super-brain" produced.

Anyway, it looks like experimentation is required. Good luck.

https://www.311s.org/su-setup/su-setup.html

Dashpot Oil

 

On acceleration the mixture needs to be richer or you will get stumbling. The oil in the dash pot slows the rise of the piston. The piston being lower than it wants to be causes the mixture to be rich. Generally speaking you want to use the thinnest oil that stops stumbling on acceleration. Roadsters tend to be quite tolerant of running rich so thicker is better than thinner. However, too thick will over richen and cause the acceleration to feel flat. The correct thickness will have a crisp acceleration. The factory spec is 10w. That is in the range of ATF and MMO. 3 in 1 is thinner. In one Z I did I ended up with 50w before it would accelerate cleanly. The synthetic oils do tend to be thinner than regular oils so I'm not sure what the "real" viscosity of the synthetic is. Motorcycle fork oil works well, comes in convenient bottles, and in lots of weights. Single weight engine oil comes in 20, 30, 40, and 50 weight but I haven't seen 10w. If you're being fiddly you can mix weights to come up with in between weights. I use fork oil for the thinner weights and single weight engine for the thicker.

 

I get it.

I do go to the source material many times but ultimately the list is what I'm looking for. It's also interesting how many times I see AI pull up information that doesn't show up in my own search results

My Ztherapy carbs came with SM needles instead of the stock N27. I think the SM needles run a bit richer.

FWIW, I have always used 3-IN-ONE oil for my dashpots, in the years before my resto and later in my rejuvenated Z Therapy units. Great response in all operating situations.

59 minutes ago, jfa.series1 said:

FWIW, I have always used 3-IN-ONE oil for my dashpots, in the years before my resto and later in my rejuvenated Z Therapy units. Great response in all operating situations.

+1 on the 3 in 1 oil, and add that I have always used the electronic motor grade.

I used this once when I rebuilt them and they still work excellent.

Edited May 18May 18 by siteunseen

So that 2 in 1 oil is 20W. I took the tranny fluid out today and added some 10W-30. I probably won't test drive it again for a few days. I will report back when I do

Well let us know how the 10W-30 fares when you get a chance to test it out.

I was asking about the needles because (as emccallum mentioned), I thought that the stuff that ztherapy did came back with SM needles. In any event, if you're still running lean with the oil change, you might want to pull a needle and have a look for confirmation.

Have you verified the float bowl level using the clear tube method? That could have some impact on mixture too.

9 hours ago, Captain Obvious said:

Well let us know how the 10W-30 fares when you get a chance to test it out.

I was asking about the needles because (as emccallum mentioned), I thought that the stuff that ztherapy did came back with SM needles. In any event, if you're still running lean with the oil change, you might want to pull a needle and have a look for confirmation.

Have you verified the float bowl level using the clear tube method? That could have some impact on mixture too.

I will

I'm hoping this will enrichen the acceleration

I can make it pretty rich now with the vacuum leak fixed and it will idle down when warm.

I have not verified the float level with the clear tube method. I'm hoping I won't have too.

I tried to reach out to Randalla about a set of FloatSync gauges but didn't hear back

Pretty sure I have a float level tube and the carb sync tool if you want to borrow them. Just let me know and I will hunt them down.

2 hours ago, Patcon said:

I can make it pretty rich now with the vacuum leak fixed and it will idle down when warm.

Yeah, I'm assuming you could simply make it richer by turning the nozzle knobs down some, but let me guess.... If you do that, it idles pig rich? And probably rich at light cruise as well?

2 hours ago, Captain Obvious said:

Yeah, I'm assuming you could simply make it richer by turning the nozzle knobs down some, but let me guess.... If you do that, it idles pig rich? And probably rich at light cruise as well?

Correct

But leans out on acceleration

Edited May 20May 20 by Patcon