1970 Datsun 240Z carb questions
1970 Datsun 240Z carb questions
With the SU carbs put in the early Z's are there 2 adjustment screws 1 for air and other for fuel or is it 1 screw for fuel adjustment and the other for idle adjustment? where is the fuel mix. screw located on the carb? Anyone who can help me out I would greatly appreciate it. Also where can i find a shift bushing? Or OEM (style) metal 240z badges? Or orig. antenna? Or what the recommended weight oil is supposed to be used?
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evildky
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- Joined: Sat Jan 31, 2004 9:23 pm
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the SU's only have 2 adjustments each, the jet screw which is a thumbscrew at the bottom of each carb, and the idle screw on the side that is used to adjust the minimum throttle opening for idel speed
the thumbscrew on the bottom of each carb should start at about 1.5 turns out, this lowers the fuel jet away from the needle thats attached to the carb piston, when working with su's forget everything you know about traditional carbs except the venturi effect
the fuel bowls on the side of each carb are pretty self explanitory, they hold the fuel and have a float and a needle valve that regulates flow of fuel into the boel, at the bottom of each bowl there is a tiny drainhole and an outlet hose, the hose leads to the jet in the bottom of the su' carb with the thumbscrew around it to allow for moving the jet up and down on the needs, when the throttle is opened up vacume draws the pistins up which in turn pulls the tapered needle form the jet allowing fro more fuel flow, to truely tune them you have to index and file the needles, it's a whole process unto itself, this is why tripple webbers are so popular
as for the carb oil, you can buy SU oil form MSA but most people simply use ATF
as for shifter bushings, the early style trans idn't use bushings, it's a very poorly designed saddle setup, you can cut and retherad the shift leaver but not much you can do to firm up the feal short of swappin to the later 71.5 and up style trans, of course it's not a bad idea to swap to a 5 speed at the same time for more comfortable freeway cruising
badges and antenna, MSA, blackdragon, and courtesy parts are the leading suppliers, there are tons of smaller companies specializing in hard to find bits but those are the best resources in general
the thumbscrew on the bottom of each carb should start at about 1.5 turns out, this lowers the fuel jet away from the needle thats attached to the carb piston, when working with su's forget everything you know about traditional carbs except the venturi effect
the fuel bowls on the side of each carb are pretty self explanitory, they hold the fuel and have a float and a needle valve that regulates flow of fuel into the boel, at the bottom of each bowl there is a tiny drainhole and an outlet hose, the hose leads to the jet in the bottom of the su' carb with the thumbscrew around it to allow for moving the jet up and down on the needs, when the throttle is opened up vacume draws the pistins up which in turn pulls the tapered needle form the jet allowing fro more fuel flow, to truely tune them you have to index and file the needles, it's a whole process unto itself, this is why tripple webbers are so popular
as for the carb oil, you can buy SU oil form MSA but most people simply use ATF
as for shifter bushings, the early style trans idn't use bushings, it's a very poorly designed saddle setup, you can cut and retherad the shift leaver but not much you can do to firm up the feal short of swappin to the later 71.5 and up style trans, of course it's not a bad idea to swap to a 5 speed at the same time for more comfortable freeway cruising
badges and antenna, MSA, blackdragon, and courtesy parts are the leading suppliers, there are tons of smaller companies specializing in hard to find bits but those are the best resources in general