Carburetor Central
If you have questions about the SU Carburetors, this is where you can find the answers.
Subforums
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I currently run a great set of 151's on my 2.8 powered 240Z. They run great, except for a bit of a "gasp" if I slam open the throttle below 2500rpms. Normal throttle, and spirited throttle application work fine. I just acquired a set of 18's that I planned to clean up and sell. In your opinion, should I swap to the 18's to see if they run even better? I know the 18's are supposed to be better for the L motors, mainly due to the progression design. Opinions? Sell the 151's or the 18's? Both sets are 40DCOE and I can choose 30 or 32mm chokes.
Last reply by LeonV, -
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I'm shaving off all of the pollution control stalks, plugs and the rest of it that covers the balance tube to give it a cleaner look. I would like to relocate the brake booster vaccum hose into the end of the balance tube closest to the firewall (at the moment it's connected to the top of the balance tube) Just wondering if changing the location of that vaccum port could affect the brake booster function in anyway? Thanks. Chris
Last reply by LeonV, -
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I'm having some trouble setting the correct position of the needles. I have always used the methed of placing the needle on the piston and tightening the set screw just enough to cause some drag on the needle but allowing it to move freely, I then place the piston onto the carb and let the needle position itself. My problem now is that when I place the piston onto the carb I slowly lower it down and I can feel the needle bottom out, I then slowly pull the piston back out and the shoulder of the needle is sitting above the surface of the piston. I have read another method is to use a straight edge along the bottom of the pistion and use that as reference for the needle he…
Last reply by madkaw, -
Hi, I'm a new Z owner. The car came with a Bob sharp and Holley 8007 390 cfm 4 barrel conversion. The carb secondary vacuum barrels were seized probably since he garage it 12 years ago. I tried a rebuilt kit but still had problems and I didn't trust it as a daily driver. So being new to carbs I asked around and was advice to just replace them. I purchase a new Holley 600 cfm 4 barrel carb thinking that more cfm is better. Now the car turns on with minimum effort and idles ok. Once the motor warms up I open the choke and it starts to idle high and goes up and down in idle from 800 to 1200 and seems as though its running rich. Ive revived all the way just to see where recli…
Last reply by LeonV, -
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The parts catalog refers to this item as "Stopper - idle." Can anyone explain what this part does? Mine have gotten totally loose. Maybe it's sometimes referred to by another name? Two visuals attached. Thanks hugely in advance.
Last reply by SteveInOakland, -
- 7 replies
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I just got my '72 240z running again, for about 5 seconds. I installed a Carter P60504 electric fuel pump with an advertised shut off of 4psi. From what I have read the SU's do not like anymore than 3.5psi. Upon turning the key and letting the system prime fuel started pouring out of the air cleaner/intake side of the carbs at the bottom of the large opening. I unplugged the fuel pump, waited a minute, turned the key, and the car would run until it emptied the fuel in the carbs. So my question is, if the floats and needles are working properly would the keep fuel from filling up the carbs and leaking out? If my floats and needles are fine then I am pushing too much …
Last reply by Hardway, -
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I just discovered that the nozzle on my front SU is loose. This is the fuel feed nozzle on the bottom, please see attached photo and illustration. It's loose, as in I can rotate it with my fingers, to the limits of the two attachments. Since the mixture adjustment nut is right there, I'm hesitant to try tightening things before I know what I'm doing. What can I do to get this thing tight? These are 4-screw SUs, btw. Thanks in advance for any and all help.
Last reply by SteveInOakland, -
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I just ran it tonight with 29mm fuel level (measured from top of main well). Is 25mm down a typical level for an L24? (i.e. my fuel is 4mm too low)? Thanks
Last reply by 240260280z, -
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Hi, After watching Just SU DVD so many, I decided to rebuild my '72 3 screws SU carb. It took me 3 hours to clean up 1st carb to remove 40 years gank, but 2nd one took me just 1 hours. Following DatsunZgarage instruction and use clear tube to adjust float level for both SU carb. http://datsunzgarage.com/engine/index.htm http://forums.ctzcc.com/viewtopic.php?t=4181&sid=b15c6070a9563fa4173bb07bbd52d213 It took me so many times to adjust float setting matching to 23mm line for both carb. Them, put back everything, spray Engine Start Spray, it start a bit and stole. Adjusting choke level, nothing is improving. No matter what I did, when I spray, it runs a bit a…
Last reply by tamo3, -
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The main jet, emulsion tube and Air corrector all must hold hands in order for the main circuit of the car to act as it should and when it should. Understanding the function of each part is critical to being able to tune the car. Blue has done so many great explanations of carbs, interiors, etc that I thought I would try to add to some of the core knowledge on the board. I am by no means an expert, but at times, I have been told I can explain things in a very easy to understand manner. So lets talk about the air corrector on Webers (or Mikuni's I guess as well). The air corrector allows air to come into contact with the fuel coming form the main jet and then enter t…
Last reply by 240260280z, -
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Cleaned the needle valve and tried the blow test. The pin on the valve hangs down about 1/8 inch or so. About half of that is free play. The valve closes just when the spring is felt. It tests OK when the lid is in the normal position but if I flip it over just the weight of the pin (no float attached) is enough so you can't air blow through. Is that correct or is the spring too weak? BTW noticed alignment of the hose bib of the banjo with one of the holes in the bolt causes more air (gas) flow. If the holes are off and the lap of the filter screen happens to cover the hose bib hole, it flows way less. Maybe because my screen is out of round, not new, just cleaned. …
Last reply by Stanley, -
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- 10.9k views
I am planning my build of an L28 3.07 stroker with most of the bells and whistles and I will have to decide soon on either SU's or Weber/Mikuni's. This will be a street driven car with some track/autocross. I have read a lot of the archived threads and basically it comes down to the SU camp saying that SU's can handle all the air needs of an L28 and therefore triple weber/mikuni's aren't needed. The Weber/Mikuni guys saying there is lots more HP hidden that the triples bring out. So who is right? I am not in either camp at the moment but I would like to see the numbers, SU's are simple and easily maintained, triples look good and sound AWESOME but I don't want to s…
Last reply by LeonV,
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