1972 Float Adjustment ...

[jalexquijano]

6 minutes ago, Mark Maras said:

  Cliff (Siteunseen) recommends RTV. It will work just fine. Keep adjusting to get that 1/16". I predict that you're going to be so quick and so good at adjusting floats that you'll be the one giving advice in the future.

Question: the float needs to be straight and parallel  or can it be bent down to achive the .055 inch gap?  

Edited February 28, 2018 by jalexquijano

[Mark Maras]

 Stop trying to set the floats by measuring them. You're getting focused on something that can be bypassed and ignored. Put away all types of measuring tools where you won't be tempted to use them. The 1/16" below the nozzle tops at 2 1/2 nozzle turns is the goal. The fuel level in the nozzles is the same as the fuel level in the float bowls. Get the fuel at 1/16" below the nozzle tops and the fuel level in the float bowls will be PERFECT. Even if you thought you had the floats set right by measuring something, to be sure they were correct, you'd pull the domes, pistons and check the fuel height in the nozzles 1/1/6",nozzles, 2 1/2, adjust nozzles, nozzles, floats, mixture, nozzles, 2 1/2, nozzles. Whoops. My LP is getting worn out and starting to skip. I'd hate to start sounding like a broken record.

[siteunseen]

1 hour ago, jalexquijano said:

Mark,

You are the best! Thanks for your patience! I know some people hate me for opening too much threads but every issue of these cars must be solved logically!

Nobody on here hates you. Don't say that.

[siteunseen]

2 hours ago, Mark Maras said:

  Cliff (Siteunseen) recommends RTV. It will work just fine. 

I used the black fuel resistant rtv just a light coat on the lid then stuck the gaskets on. I lightly screwed my lids onto a spare set of carbs, no gas in the float chambers/bowls. If you take the floats off it a lot easier. Leave overnight.  Then put the lids on your car's carburetors.

[Stanley]

I want to post this tech bulletin again. I'm still seeing references to ".55 inch", "9/16 inch",  "14 mm down", or "23 mm down" in this thread. It's in the '72 FSM  like that but all those numbers are  wrong. The official Nissan Bulletin below, posted a couple years ago by Jonathan Russell (thank you), corrects the errors. It works out to 21 mm rear and 25 mm front (plus or minus 1/2 mm) down from the lid. So it's 4 mm higher for the rear carb.  Or use the numbers in the bulletin to measure from the lid to the float if you have to try that method.

Yes, the nozzle method is more accurate and you don't need to be concerned with numbers. So it's best to use that and forget about this.  I don't like float to lid measurement method either. But if you want to use the float to lid measurement method anyway, or if you use the sightglass method, please read this at least once. It won't make it any easier to adjust the tangs but at least you'll be trying for the right numbers.

TechnicalSupportBulletin-TS73-10.PDF

[jalexquijano]

Still lean!!!!! 

[David F]

Well, what do you expect and please tell us why you are evening showing photos of the inverted float position.  Like we have been saying, it means nothing as the parts are NOT the same as when that method had any validity, if ever.  I can tell you that with the float that high off the lid, when inverted, you are not even close.  Really, you need to listen to everyone and simple adjust to 1/16" below top of nozzle at 2.5 turns down.  Start with the float just off the lid...maybe 1/8" and go from there.  As before, I suggest you remove the sealing washer between the needle valve body and lid.

[Mark Maras]

 I agree with David. That float is set too lean. Bend the float tab so the float sits a bit closer to the lid. Install the lid, fire the engine up (no need to drive it), shut it down and pull the domes and pistons and look at the fuel level in the nozzles. Be sure to do the drop test on the pistons when it's reassembled to be sure nothing is binding. .

 I'd like to congratulate you. Good to see the parts in your hand rather than a mechanic's verbal description. Keep up the good work. 

[jalexquijano]

11 hours ago, Mark Maras said:

 I agree with David. That float is set too lean. Bend the float tab so the float sits a bit closer to the lid. Install the lid, fire the engine up (no need to drive it), shut it down and pull the domes and pistons and look at the fuel level in the nozzles. Be sure to do the drop test on the pistons when it's reassembled to be sure nothing is binding. .

 I'd like to congratulate you. Good to see the parts in your hand rather than a mechanic's verbal description. Keep up the good work. 

Finally set accordingly. Ready to drive the car and report back

[Mark Maras]

 Good job. That looks closer to the proper angle. Drive it a bit and let us know how the engine feels, cold and hot. Are the mixture screws set to 2 1/2 turns? In the report be sure to tell us where the fuel levels are in the nozzles. 

[jalexquijano]

At 2.5 with the engine warmed up it stalls. Engine needs at least 3 turns clockwise and still appears lean. At 3.5 turns it tends to get better. Just remember my engine is not stock, it was rebuilt with oversize pistons and overhauled to 2.6Liters. Asides from that it has a Schneider 274F camshaft.  

I also receive a new set of needle valve and seats from Amazon:

https://www.amazon.com/Walker-Products-15568-Carburetor-Kit/dp/B000CLSRR0

https://www.amazon.com/Walker-Products-15567-Carburetor-Kit/dp/B000CLN1XK

How can i determine if the actual needle and seats need to be changed or not? Could one of them be damaged?

Edited March 5, 2018 by jalexquijano

[JLPurcell]

1 hour ago, jalexquijano said:

At 2.5 with the engine warmed up it stalls. Engine needs at least 3 turns clockwise and still appears lean. At 3.5 turns it tends to get better. Just remember my engine is not stock, it was rebuilt with oversize pistons and overhauled to 2.6Liters. Asides from that it has a Schneider 274F camshaft.  

I also receive a new set of needle valve and seats from Amazon:

https://www.amazon.com/Walker-Products-15568-Carburetor-Kit/dp/B000CLSRR0

https://www.amazon.com/Walker-Products-15567-Carburetor-Kit/dp/B000CLN1XK

How can i determine if the actual needle and seats need to be changed or not? Could one of them be damaged?

The supplied fuel tube (pipette) in the above kits can cause problems with the nozzle return. If your SU have the 45' angle nozzle then you should buy the ones offered by Datsun Parts (http://www.datsunparts.com/U20-Carburator) part#1644 pipette. it is formed correctly to allow for the nozzle to freely return to upper position.