1972 Float Adjustment ...

[Mark Maras]

 I'm not surprised. That would explain the lean condition that you told us about previously. We'll proceed with the adjusting the floats until the fuel level is 1/16" below the tops of the nozzles. It will be interesting to see where the final fuel level ends up.

[jalexquijano]

Mark,

Can you point out exactly where does the fuel level must reach in the bowl? 

[Mark Maras]

 Unfortunately, I can't. There seems to be different opinions about the fuel height in the bowls on three screw carbs. My suggestion is set the float heights by visually verifying the fuel level is 1/16" below the tops of the nozzles at 2 1/2 turns down. That way you're sure they're 100% right. I would suggest measuring the fuel height in the bowls using the tubes AFTER the floats are set. That info could be valuable to others.

[jalexquijano]

Good. Well the good news is that this morning at 7:00 a.m. I managed to install the new airtex 8012s electric pump which arrived from amazon yesterday and now i am back at 4.2 psi. Now i can take both carb floats out and push the tang to richen the carbs.

 

[Mark Maras]

Progress is good. Keep us posted.

[DaveR]

(This is for 4 Screws if that matters) For what its worth, with Ztherapy's new grose jets... the old method of setting the gap above the floats to the the Bowl lid didn't work at all for me.  The jets didn't shut off at the expected height or anywhere near it. They also didn't hold up the weight of the float because the new design was not sprung open the same way. It was a futile effort.

The way I did it was the hard way, eyeball the tang location, install the Lid and pulse the starter motor with the Dizzy plugs undone so the mechanical pump filled up the bowls but the car didn't start.  If I overshot I sucked fuel out of the bowls, adjusted the tang to lower the fuel level and did it again. 

Rinse and repeat until the fuel level was barely above the top of the Nozzles top edge when it was 10? turns down.  Took a while but worked the best of all the methods considering how far I was off doing the other methods.  I'm not sure where the 2.5 turns in this thread comes from, but when I was doing it this past summer everywhere I read used 10 turns for the method I used, and the car feels good and tuned well once I returned the nozzles to their original location and tuned from there.

 

Edited February 23, 2018 by DaveR

[Mark Maras]

@DaveR, was the 10 turns down setting with the floats removed? What was the "original location" that you mentioned?

[DaveR]

If you look around this forum, (it may have even been in this thread or posted by those I am replying to) the method I found for setting the proper float levels was...

1) Adjust your fuel nozzles all the way to the top, so the top of the nozzle is flush with the bushing in the carb housing. (If its not maybe there are pieces missing in the stackup of hardware, not sure.)

2) From there back the nozzles down a full 10 turns of the fuel adjustment. Its quite far. 

3) At this point you want the fuel level when the bowls are full to be at the exact top of the nozzles in their lowered position. If you shine a flashlight you can see the fluid kind of "doming" as it reaches the top but hasn't spilled over.  (I found it easier to actually go like 9-9.5 turns and have the fluid lower in the nozzle. Then as it turned it to 10 turns watched to see if the fluid changed or spilled over the top as I passed 10 turns.)

4) Once you have this fuel level set correctly your floats are done. You raise the nozzles up all the way to the top, and then back them down the 2.5 turns which is your "starting point" for tuning.  From there you can adjust to get maximum airflow and maximum RPM (richness/lean-ness)

I'm far from a carb expert, I'm only 34... but this is what my research on this exact forum showed as the most foolproof way to set the float levels especially given my inconsistent results with the Float to Bowl Lid gap method that Ztherapy's DVD calls for.

I could be totally off on all this, but my car runs pretty well and tuned as expected so I don't think I am way off base.

Edited February 23, 2018 by DaveR

[jalexquijano]

39 minutes ago, DaveR said:

If you look around this forum, (it may have even been in this thread or posted by those I am replying to) the method I found for setting the proper float levels was...

1) Adjust your fuel nozzles all the way to the top, so the top of the nozzle is flush with the bushing in the carb housing. (If its not maybe there are pieces missing in the stackup of hardware, not sure.)

2) From there back the nozzles down a full 10 turns of the fuel adjustment. Its quite far. 

3) At this point you want the fuel level when the bowls are full to be at the exact top of the nozzles in their lowered position. If you shine a flashlight you can see the fluid kind of "doming" as it reaches the top but hasn't spilled over.  (I found it easier to actually go like 9-9.5 turns and have the fluid lower in the nozzle. Then as it turned it to 10 turns watched to see if the fluid changed or spilled over the top as I passed 10 turns.)

4) Once you have this fuel level set correctly your floats are done. You raise the nozzles up all the way to the top, and then back them down the 2.5 turns which is your "starting point" for tuning.  From there you can adjust to get maximum airflow and maximum RPM (richness/lean-ness)

I'm far from a carb expert, I'm only 34... but this is what my research on this exact forum showed as the most foolproof way to set the float levels especially given my inconsistent results with the Float to Bowl Lid gap method that Ztherapy's DVD calls for.

I could be totally off on all this, but my car runs pretty well and tuned as expected so I don't think I am way off base.

Maybe i should try it later on when i become an expert. At the meantime ill keep up with Mark´s advice.

[NVZEE]

1 hour ago, DaveR said:

For what its worth, with Ztherapy's new grose jets...

Not wishing to hijack this thread, but is there a new Grose Jet? They went NLA awhile back — just curious.

[DaveR]

The attached image is the method often called for to set it initially, including what ZTherapy's DVD shows. This is what did not work AT ALL for me, because the grose jets that Ztherapy sent me no longer can support the weight of the float and made the adjustment very different from what the original intention was. If you use original jets with stronger springs then you can probably still use the original method. 

----
For the Z therapy jets....technically what this image is illustrating is that at this height of the float, you want the grose jet to close and the fuel to shut off.  I tried to simulate this by running a hose to the inlet port and pressurizing it by blowing in to. As I moved down the float I noted when the grose jet closed, and at THAT point in the travel, the gap from the lid to the float should be the 9/16"

In actuality this didn't work and my levels were way off. So I did it the more cumbersome way by replacing the lid and float assembly each time I needed to adjust the tangs.
----

I even called Ztherapy to ask about this and was basically told that the adjustment method used in the video wasn't valid any more with the style of grose jets they use now. (I can't swear this applies to anyone else besides me, but that's what they said to me) I attached a picture of my float assembly which shows it being very droopy because the spring that forces the grose jet open wasn't strong enough to hold up the additional float weight so it just compressed. I had to bend my float bracket to such an extreme level to get the measurement that it didn't look right. If I recall correctly it made my fuel level way too low.

 

 

 

As for the grose jet... I don't know if the Nissan one went NLA... I used the Ztherapy ones.  

Edited February 23, 2018 by DaveR

[jalexquijano]

6 minutes ago, DaveR said:

The attached image is the method often called for to set it initially, including what ZTherapy's DVD shows. This is what did not work AT ALL for me, because the grose jets that Ztherapy sent me no longer can support the weight of the float and made the adjustment very different from what the original intention was. If you use original jets with stronger springs then you can probably still use the original method. 

----
For the Z therapy jets....technically what this image is illustrating is that at this height of the float, you want the grose jet to close and the fuel to shut off.  I tried to simulate this by running a hose to the inlet port and pressurizing it by blowing in to. As I moved down the float I noted when the grose jet closed, and at THAT point in the travel, the gap from the lid to the float should be the 9/16"

In actuality this didn't work and my levels were way off. So I did it the more cumbersome way by replacing the lid and float assembly each time I needed to adjust the tangs.
----

I even called Ztherapy to ask about this and was basically told that the adjustment method used in the video wasn't valid any more with the style of grose jets they use now. (I can't swear this applies to anyone else besides me, but that's what they said to me) I attached a picture of my float assembly which shows it being very droopy because the spring that forces the grose jet open wasn't strong enough to hold up the additional float weight so it just compressed. I had to bend my float bracket to such an extreme level to get the measurement that it didn't look right. If I recall correctly it made my fuel level way too low.

 

 

 

As for the grose jet... I don't know if the Nissan one went NLA... I used the Ztherapy ones.  

Well i tried to set mine to .55 inch barely touching the tip of the needle valve and its still lean. Ill guess ill need to bend the tang more.