1972 Float Adjustment ...

[Mark Maras]

 Thanks for the reminder. We never did get to the bottom of that. @jalexquijano What about the low compression readings the last time around? My assumption is it was either a botched compression test or the valves were set to tight. Do you have an explanation?

[Zed Head]

Don't forget that the extensions used on the tester add to compression chamber volume.  So you'll get a lower number if you use the big pipe extension on the tester.  But, it is a California Datsun motor.  Might be a P79 or P90 head on a dished piston short block.  Knowing the head number/model would help the puzzle.

As far as faster takeoff in first, the rear diff ratio needs to be known.  And whether the 5 speed is a 280Z or a 280ZX unit.

[Johnny wick]

35 minutes ago, Mark Maras said:

 Thanks for the reminder. We never did get to the bottom of that. @jalexquijano What about the low compression readings the last time around? My assumption is it was either a botched compression test or the valves were set to tight. Do you have an explanation?

Plugs 4 and 3 

[Mark Maras]

@jalexquijano LOOKIN GOOD. The plugs are definitely lighter than we used to run the "back in the day" but you report the engine is running good so I'd leave it alone. I think the problem with #4 was in the cap, rotor or plug wire connection. #4 definitely looks better now. The lighter plug color could be due to modern gas formulations as reported by others. I'm still curious about that previous lower compression reading. I'm hoping it was a poor test and not tight valves. Any thoughts?

[Johnny wick]

I am still wondering if i should strive to get that precise measure of 2.5 turns clockwise by closing the gap a Little bit more on the front and rear float bowls.

[siteunseen]

I would be more concerned with the low compression readings you posted. You say the car is running good, why not drive it and do as you said "please calm down"?

https://www.classiczcars.com/forums/topic/47304-1972-float-adjustment/?do=findComment&comment=553023

[Patcon]

Nope!!! Drive it and enjoy...

[Mark Maras]

15 hours ago, jalexquijano said:

I am still wondering if i should strive to get that precise measure of 2.5 turns clockwise by closing the gap a Little bit more on the front and rear float bowls.

 @jalexquijano If you're curious, go ahead and turn the nozzles up about a quarter turn. easy enough to do and undo. However, the previous compression test is still troubling. If the valves are too tight there could be an expensive repair bill in the near future. I would find the reason for the low compression first. Personally I think it was a botched test but maybe that's just wishful thinking on my part.

[Mark Maras]

@jalexquijano A few more thoughts about adjusting your SUs. Make one adjustment at a time. It's fine to adjust both carbs at the same time but don't do anything else until you've driven it for a few days. If you really want to try adjusting the nozzles to 2 1/2 turns, consider this. One turn of the nozzle adjustment screw is 1 mm. Theoretically. if your nozzles are at 3 1/2 turns down you could raise them to 2 1/2 turns down and raise your floats 1 mm to compensate. Anyone out there have any thoughts on my theory? 

 I'm still curious about that last compression test.

[Captain Obvious]

34 minutes ago, Mark Maras said:

 Theoretically. if your nozzles are at 3 1/2 turns down you could raise them to 2 1/2 turns down and raise your floats 1 mm to compensate. Anyone out there have any thoughts on my theory? 

My thoughts are that I don't think you can equate those two things like that. Two completely different factors and not necessarily linear or equivalent.

I'm no carb expert, but I would not agree with that theory even a little bit.

[Mark Maras]

 Thanks Cap'n. I was hoping you'd respond. I had that nagging thought that it sounded too darned easy and logical. Anyone else want to chime in?

 @jalexquijano Ignore my last post to you. Leave the floats alone. (Everyone can breathe a sigh of relief) If you want to lean it out a bit (1/4 -1/2 turn) to see how it runs, try it. Most of learned by trial and error. Remember, your plugs looked nice and clean at the current settings and it runs good.

[Johnny wick]

The misfire issue due to carbon fouled plugs was clearly because i pulled the choke knob all the way and left it running 2 mins with the choke fully on while the engine got warm.