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Stripping out Emissions Stuff

Discussion in 'The Garage' started by Justin Fleming, Aug 27, 2005.

  1. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    The charcole canister finally broke down on my 86 k5 and the carb is plugged full of it. I guess it gives me a reason to rebuild the carb. Anyhow what can I get rid of and what should I try and keep as far as emissions controls stuff? I do not need the truck to pass emissions test.....

    Questions:

    Should the vaccum advance for the distributor come off of the base plate of the carb or a intake port?

    How should the cruse vaccum be hooked up?

    I know there are lots of little electronic solenoids and things of that sort that I am unsure of what they do.


    Thanks

    Justin
     
  2. sled_dog

    sled_dog 1 ton status

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    Vaccum advance should go to a ported vaccum port on the carb. If you hook it up to the intake you will have full advance at idle :eek1:
     
  3. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    So then it should be a vaccum port above the base plate of the carb....


    Thanks
     
  4. Triaged

    Triaged 1/2 ton status

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    Replace the carbon canister. It is what vents your gas tank. It is cheeper and works better then a rollover valve.

    Putting the vacuum advance on the ported vacuum was for emissions. I have mine on full manifold vacuum and the motor loves the 30deg of advance it gets at idle. Plug it, set the base timing, try it both ways, use which one you like best.

    "I know there are lots of little electronic solenoids and things of that sort that I am unsure of what they do."
    If you don't know what it is, what it does, and how it does it leave it.
     
  5. 1979jimmy350

    1979jimmy350 1/2 ton status

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    its not that good of a idea to put the advance on manifold vacuum. When you need advance the most is at higher RPM where manifold is low so it would pull your advance back. If you think you need more advance at idle you should advance your distributor and your engine will run a lot better
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    My original cannister broke too , little black bits in the carb 4 years ago .

    I went to a yard and pulled a 1978 one .

    I omitted all the vacuum switches , used a 79 c-10 water neck with one hole for my temp sender .

    I simplified it for myself since its never real cold here .

    Emissions won't hurt performance . If I can roll with a 305 with the a/c on , its not hurting performance :wink1:
     
  7. sled_dog

    sled_dog 1 ton status

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    actually ignition advance is because at high RPMs your engine is trying to do the same thing its doing at 1000RPMs just a LOT faster. Combustion takes the same amount of time at 1000RPMs as it does at 6000RPMs, making it start sooner just helps to get it done and not have unburned fuel, which will hurt emissions yes but also power. Having unburned, unused fuel is just a waste of horsepower, can't make power from unburned fuel.

    You should realize that as RPMs increase, your manifold vaccum is decreasing and you are LOSING advance. Thats why you run it on Ported vaccum. Its nearly 0 at idle, but ramps up as the butterflies open. It eventually falls off as well, but thats what centrifugal weights are for(to take over when vaccum is gone).

    And I agree, if you don't know what it does, don't remove it. Study it, learn what it is and does, then figure out if you can remove it. Most people remove emissions stuff that is of no gain and only hurts emissions. Personally I'd rather emit less and deal with a few more hoses... not that I haven't just ripped handfuls of vaccum lines out already.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Manifold vacuum theoretically nets you better idle, at the expense of emissions.

    Look at advance on computer controlled chev motors at idle (20+) compared to what you are stuck with using ported vac/mechanical advance.

    That much advance at idle won't hurt a thing, at startup you aren't pulling enough vacuum to make initial startup difficult. Ported vacuum simply cuts out the idle portion of the vac advance. GM ran it both ways, very rarely later on was manifold vacuum used.
     
  9. diesel4me

    diesel4me 1 ton status Premium Member

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    Tried both ways..

    I tried hooking my vacuum advance up both ways on my 86 305 motor I put in my 79 C10--it used to have the electric Q-jet and the multi-pin module HEI,with no vacuum advance--but I put a 1976 305 HEI in it and used an Edelbrock Performer...I swear it runs better on manifold vacuum than ported!--.
    I tried running it both ways..I get better mileage with manifold vacuum,and a much smoother idle! :eek1: exactly the OPPOSITE of all the other chevy's I've had..maybe the advance curve on later motors is way advanced compared to the older non "EST" HEI distributors are??

    If I run ported vacuum,I have to advance the timing manually so much it pings(even setting it to factory specs,it pings)..it seems better with it advanced at idle by manifold vacuum--and when you get on the gas,it retards the spark,and avoids pinging..I know this isnt how most GM cars are plumbed--but it seems to be the best for my 305.... :confused: :crazy: With gas prices the way they are,its staying the way that gives the most gas milage! :crazy:
     
  10. Triaged

    Triaged 1/2 ton status

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    These are some very good posts that i have cut/pasted from another forum for your viewing pleasure.



     
  11. surpip

    surpip 1 ton status

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    why is everyone so intent on pulling all there emissions stuff off? It really(on the newer motors) dose not harm your performance that much, and it makes the air we breathe cleaner
    why not just ask which is the best way to dump used oil in the river?, or, How can i make more crap come out of my tailpipe so people choke when my truck passes by. :rolleyes:
     
  12. sled_dog

    sled_dog 1 ton status

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    I 100% agree, I've removed stuff I had no reason to, never again. My S10 is COVERED in useless lines, but even though its a trail only truck, its likely getting a carbon canister, PCV valve, and maybe Cats on it.
     
  13. R72K5

    R72K5 Banned

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    heres what i do on vehicles i get

    ill leave smog pump system alone if its intact and working condition, but if the pump is locked or tubes rotted or something else then ill yank all the hoses and unplug all the wiring

    EGR i always remove and put on a plate on the intake where it was, no matter the vehicle

    the TVS sweitch in therm housing i awlays unplugg hoses and bust the plastic tops off them and thats it, altohugh now and then ill get water pipe thread plugs and replce the switches with the plugs, from plumbers supply, they are regular old pipe thread(hint/tip)

    the carb if its electronic controlled and the HEI if it is electronic then i will definitely yank in favor of 79 older stuff, or 80s 3/4 or 1 ton units,

    then i will remove the entire ECM harness and the ECM(if smog pump system is bad, but if it works then i leave wiring harness alone other than unplugging carb and HEI and TVS's and 02 and knock and MAP and such)

    cat convedrs usuallyh always has been removed by a PO, i dont think ive hjad a chevy truck yet that still had the converter on it, cat converters were on all 48 state federal '75-80 under 6200 gvrw and 81-up under 8200 gmrv vehicles, cars trucks vans, gas engine anyways

    good luck
     
  14. ike

    ike Registered Member

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    which is the best way to dump used oil in the river?,

    J/k
     
  15. Justin Fleming

    Justin Fleming 1/2 ton status Premium Member

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    when no one is looking...
     
  16. Executioner

    Executioner 1/2 ton status

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    Have you ever considered changing your routine ?


     
  17. R72K5

    R72K5 Banned

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    screw you too Executioner

    i was just posting info to help Justin with his Q

    damn people
     
  18. myraley

    myraley 1/2 ton status

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    I know this is an old post, but I was trying to sort out my charcoal cannister, and I have one line that goes to the PCV and one to the carb. Does it matter where on the carb it goes? full vacuum or ported? Thanks, Eric
     
  19. AZ79K5Project

    AZ79K5Project 1/2 ton status

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    There should be a diagram under the hood. Here's a pic from my 79:
    emission 800x600.jpg

    emission 800x600.jpg
     
  20. myraley

    myraley 1/2 ton status

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    Holy Moly! I followed the maze, but I didnt find any cheese at the end! Now I see why people take that stuff out! It looks like I'll go buy a bunch of vacuum t's tomorrow. Thanks!
     

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