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Will these carbs fit on a Z24?


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Anything will fit anything else with the proper intake manifold. You'll need a Z24 intake that will accept Mikuni Solex side drafts.

 

 

Before you go hog wild.

 

Your '86.... is it a Z24i with two wing nuts holding the air filter on? If yes, I'm afraid this won't work without swapping more parts on.

 

Are you aware that the Z24 is very performance limited because of head design? Side drafts are a little overkill and won't reach their full potential. You would get the best bang for the buck with a 32/36 downdraft Weber kit. >$300 and includes an adapter plate. Side drafts are almost worth $1,500 plus intake just for the sound!

 

 

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These are on my 1985 right now. I can't find the model number or model name. The listing on ebay is just a backup just incase I get no info on the carbs I have now. If I can get help identifying the carbs I have now, I could just look for a rebuild kit. This is the best picture I have of them.

 

https://drive.google.com/file/d/1HMNYhjzgac5meRJedONzPjixvY5J5goU/view?usp=drivesdk

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1 hour ago, KAIKZ720 said:

 

Could anyone tell me if these carbs linked below would fit on a z24? I have a 1985 Nissan 720 standard cab. Any info will help. Thank you!

 

https://www.ebay.com/itm/MIKUNI-SOLEX-40PHH-TOYOTA-KP61-KE70-/133837480220?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=711-127632-2357-0

Theres a good chance they are the same,  but as Mike said you dont need the intake....

They do have 40 and 44 so I'd take some measurements to see what you actually have.....

You could have yours rebuilt instead....

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Also plumb in the fuel return line. If you are having problems with your current carbs without the fuel return line you very well could be forcing too much fuel past the floats without a place for excess fuel to to move past the carbs and return to the tank.

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Thank you for the laughs. This truck was passed down to me and whatever was done to it wasn't my own doing 🤣

 

But thank you for all the replies. Im very new to these type of things and I appreciate any sort of feedback or info. 

 

Thank you all. Maybe in the future you'll see my build progress!

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Screenshot_20210812-174107_Drive.jpg

 

I would tuck the front hose down between the two front horns and the rear hose behind the rear trumpet and shorten all lines and join under and between the two carburetors. The center hose cut, add a T and point down between the carburetors and connect to the return line.

 

 

1 hour ago, Logical1 said:

Also plumb in the fuel return line. If you are having problems with your current carbs without the fuel return line you very well could be forcing too much fuel past the floats without a place for excess fuel to to move past the carbs and return to the tank.

 

The return line doesn't really modify the fuel pressure. That isn't it's purpose. If some is by passed back to the tank, the pump will automatically adjust as it is a regulated pressure. The regulated pressure is 2.7 to 3.4 PSI. The purpose of the return line is to constantly circulate fresh cool gas from the tank past the carburetors. This prevents gas in the lines soaking up heat when running. If the gas boils after a hot shut down in very hot weather the vapors will be pushed back into the tank and fresh cool gas exchanged. The return line has to have a restriction, a pin hole, so that the pump pushes against it and the pressure goes up to the regulated pressure. Another advantage of the return line is that slowly, as you drive the contents of the fuel tank are filtered over and over keeping the tank and lines free of any sediment. 

 

This is the restriction on an L20B engine. The 720 will have something similar. If it was just fully open, gas would simply take the easy path back to the tank.

 

11aMYIJ.jpg

 

 

BTW, those trumpets are all different lengths. There is a certain amount of power and torque gains from tuning the lengths but they must all be the same. In very general terms longer tubes favor torque in the mid range. Shorter favors higher RPMs.

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57 minutes ago, datzenmike said:

The return line doesn't really modify the fuel pressure. That isn't it's purpose. If some is by passed back to the tank, the pump will automatically adjust as it is a regulated pressure. The regulated pressure is 2.7 to 3.4 PSI. The purpose of the return line is to constantly circulate fresh cool gas from the tank past the carburetors.

 

Respectfully disagree. If the return line did not modify fuel pressure you wouldn't need the restricting nipple and fuel would just flow past the carbs in the LARGER fuel return line without pushing into the float bowls. The brass levers that control the float needle valves can easily get warped from over pressure. The stock 720 electric pump is designed to push the correct pressure obviously but was also designed to work with the designed return line and restrictor.  Thus between the stock pump, return line and restrictor correct fuel pressure is maintained. The fuel pump is not an intelligent system, it works in combination with the other factory designed plumbing. 

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The pump is internally regulated. Lets for argument's sake say the pump you have is putting out 3 PSI. It's chugging along slowly just maintaining the 3 PSI against the carburetor use and the return line 'leakage' through the restriction. When the float opens the needle valve for more fuel, the pressure will try to drop (very slightly) but the pump simply speeds up and pressure is maintained at 3 PSI because that's the regulated pressure. If you were to pinch the return line hose and close it off the pressure would not go up because again it is regulated at the pump to keep a steady pressure of 3 PSI. Once at a steady 3 PSI the pump will stop pumping and wait.

 

The regulated pressure of 3 PSI is in spite of the leakage back to the tank, not because of it. Now I agree that if the hole was made larger and larger at some point the pump just couldn't keep up and the pressure would begin to drop. Respectfully....

 

If you have a fuel pressure gauge pinch the return closed. You'll see that the pressure does not go up but remains steady and the pump may slow down. Release the pinch and the pump may speed up to maintain the 3 PSI or what ever your pump puts out.

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Here is some good info - http://www.wolfcreekracing.com/index.php?option=com_content&view=article&id=69%3Amikuni-carburetor-id-guide&catid=30&Itemid=51

 

I really hate to see Mikunis get snatched up by someone who doesn't need them. They are getting hard to find, especially the older ones.

 

If you want to buy or sell Mikuni or Solex carbs of any vintage, or have some restored, there's no better person than Mike Malone. He's on IG as topkart11.

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