dat240z71

Tripple Weber Hepl in Indiana

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    I'm in need of someone that knows how to tune webers.I have a L28.20 over Ported and polished N42 head,Robello street cam.flat top piston 280zx distributor that I can't seam to get running correctly.  The car has a slight bog at 2800 RPM. Bseam to hit a wall at 4k RPMS. My trimming is set to 20 degrees at idle vacuum advance disconnected.  Distributor have not been re curved.  Driving at highway speeds the car seams to bog when press down on the accelerator. The transition isn't smooth from idle circuit to main. If there anyone or a shop in N.E Indiana or the surrounding area that can help I will greatly appreciate it. I'm also willing to Compensate you.

    Jetting

    Idle jet 60 F9

    Main jet 135

    Air corrector 180

    Emulsion tube F2

    Pump jet 45

    34mm Choke 

    Edited by dat240z71

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    There is a current thread on tuning DCOE's on L28.  It may be helpful.

     

    Do you have 40's or 45's?

    Please measure your fuel height in all 3 carbs and make sure your linkage is synchronized.

     

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    Just went out and looked at the carburetors after reading the post suggested. My throttle plate sits behind the 1st progression holes I'm going to adjust them as per the pictures will report back in a little bit what I found 

    20170901_125839.jpg

    Edited by dat240z71

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    I set the plat at the edge of the progression holes can't get the idle under 1500 RPMS at that setting . No ai don't have an 02 sensor no a wideband 

    Edited by dat240z71

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    I will go out today and play with the car and report back. One question I do have is do you guys think the problem I'm having in the high rpm range could be timing  related. I do not have a digital readout timing light so I have set my idle at 20゚ but I have no idea what my total timing is do I need to look into that 1st. 

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    Yes, 20 at idle is most likely too high. It depends on what distributor you have.

    You need to buy a timing light (preferably one with advance) to measure your timing at different rpms.  The max timing you want is ~ 36 to 38 at 3000 rpm or above.

     

     

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    I have1979 280x distributor it haven't been re curved.  Vacuum advance disconnect.  When I get the new timing light do I want to set total advance. 

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    I checked specs and all 280zx distributors gives 17 degrees of mechanical advance.  If you put 20 degrees of initial advance in then you are 37 total so it would be in the ball park.

     

    Too much advance under load at higher rpms will reduce power and may ping.

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    I got the timing set today at 33% runs best at this setting  38 seam to high. Anyway  I swapped out the 135 main jets with the 145 the car runs a lot better and pulls all the way to 5500 RPMS  now before running out of fuel aith the 135 main jets and the timing  not sst correctly the would run out at 4k RPMs . I have a set of 150 main jets I'm thinking of trying tomorrow to see if  that would  be enough to pull 'll the way to 6500 RPMS .  Still have a slight hassation from about 2500-3200 RPMS.  But pulls like hell from 3500-5500 RPMS.  The Throttle plate is just at the edge of the progression holes,  the car idles at 1500 at this setting. When the plate is in the center of the progression holes or fully covering the holes other idle jump to 2000 RPMS. I'm thinking of trying 65f9 idle jets next.   Also have the occasional  spitting out of one of the carberator  and popping out the exhaust  .  My thinking is this is a street car and most of my driving is under 3000 RPMS.  So get the transition speeds figure out first then wide open throttle  5500 and above. At 3000 RPMS I cursing 70 MPH . Any thoughts will be greatly appreciated. . 

     I attached a picture of the spark plugs please help me read them 

     

     

    20170902_210528.jpg

    20170902_210448.jpg

    Edited by dat240z71

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