How the SU carburettor works - Part 1

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  • Опубликовано: 20 дек 2024

Комментарии • 63

  • @Breezey1983
    @Breezey1983 18 дней назад +1

    The best video I’ve seen explaining the workings of a carburettor 👍🏻

    • @ACDodd
      @ACDodd  18 дней назад +1

      There is more parts yet!

  • @jonathandavies7462
    @jonathandavies7462 23 дня назад +1

    Superb 👍…As Mini(etc) owners, I’m guessing we know 70% of this…but the 30% you teach us , is both fascinating and of course critical to running and tuning….thankyou 👍

    • @ACDodd
      @ACDodd  23 дня назад

      I would guess on average most are below 30%!

    • @somebloke5565
      @somebloke5565 4 дня назад

      @@ACDodd Agreed, the less they know the confident they get!

  • @rolandeid448
    @rolandeid448 26 дней назад +1

    Amazing video!
    As a mini owner who tries to keep my car running, I find this content very useful and informative. Thank you so much for sharing this knowledge.

    • @ACDodd
      @ACDodd  26 дней назад +1

      Glad you like them, please like and subscribe to my channel, this is your way of easily supporting me as this grows, and will enable me to add more content.

  • @CheekyOllie
    @CheekyOllie 28 дней назад +1

    Never understood how the piston was pulled up. Now I do!!! Good video. Thanks

    • @ACDodd
      @ACDodd  28 дней назад +1

      That’s just to point of this series it’s to explain how it works and help people make the right decisions when it comes to what they need to get their cars to run right

  • @hefinjones6213
    @hefinjones6213 25 дней назад +1

    Another brilliant video - your sharing of knowledge and experience is greatly appreciated.

  • @mikegordon2840
    @mikegordon2840 27 дней назад +1

    Your knowledge of these su carbs are amazing great video

  • @Goose_from_Norway
    @Goose_from_Norway 28 дней назад +1

    Extremely interesting video, AC. The SU is an ingenious contraption and a beautiful piece of engineering. Thanks for a great video👍

  • @forward160
    @forward160 25 дней назад +1

    Great informative video AC.. Learning all time . When you move the vacuum tube. Which process to you use to plug the old hole ..

    • @ACDodd
      @ACDodd  25 дней назад +2

      Thred the hole and plug it.

  • @rayshortall588
    @rayshortall588 28 дней назад +1

    I do like your clearly explained videos. I've been in this game for a long time,but it does no harm to listen to the whys and wherefores . By the whey, I've throne away more than enough perfectly good wax jets in the past!

  • @seanalexander9531
    @seanalexander9531 27 дней назад +1

    Excellent, thanks!

  • @Rubberduckeee
    @Rubberduckeee 28 дней назад +1

    Im enjoying my home tutoring 😁 So interesting. Thanks AC

  • @keithoftheshire2805
    @keithoftheshire2805 28 дней назад +1

    Clear and concise quality information.....👍

  • @davidgerrard8661
    @davidgerrard8661 28 дней назад +1

    Excellent, thanks

  • @sfraser12
    @sfraser12 28 дней назад +1

    Great video thanks

  • @mcmotors100
    @mcmotors100 28 дней назад +1

    Great video 👍I’d love you to explain how the Hif choke works? Thanks.

    • @flapjck1
      @flapjck1 27 дней назад

      the same rule applies

    • @mcmotors100
      @mcmotors100 25 дней назад

      @@flapjck1 it’s not the same though, it doesn’t lower the jet as it does with the HS2/4… So what does it do?

    • @flapjck1
      @flapjck1 25 дней назад

      @@mcmotors100 The adjustment mechanism is different. The principle of operation is the same

  • @ptirom44
    @ptirom44 24 дня назад +1

    Great video!
    Are there HIF carbs with ported vacuum from factory? Mine is already ported vacuum.

    • @ACDodd
      @ACDodd  23 дня назад +1

      Yes a few were made like this but the vast majority are manifold vacuum.

    • @ptirom44
      @ptirom44 23 дня назад

      @ACDodd ok thanks. As my Mini is from 1992, maybe this change was implemented quite late in the production of carbs.

    • @ACDodd
      @ACDodd  23 дня назад +1

      @@ptirom44it was, your 92 car has emission limits hence the factory adjusted the carb to ported vacuum for the same reason I do.

  • @somebloke5565
    @somebloke5565 4 дня назад +1

    Thanks AC. Good as ever Subcribed. In my application, swapping from an HS6 with level float-bowl to HIF44, where you can't level the float-chamber, carb is to be tilted at 25-30 degress. Do we have to worry re: float height?

    • @ACDodd
      @ACDodd  4 дня назад +1

      Should all be good nothing to worry about.

    • @somebloke5565
      @somebloke5565 4 дня назад

      @@ACDodd Thanks AC.

  • @pablojimenez8329
    @pablojimenez8329 28 дней назад +1

    Great video! If I’m understanding well, the momentary enrichment of fuel when opening the throttle happens because the RPMs go up faster than the piston goes up (because of the delay effect caused by the damper), thus the air velocity momentarily increases because the open cross section in the carb body is still small (piston still down) causing a higher Venturi effect in the jet-needle?

    • @ACDodd
      @ACDodd  28 дней назад +1

      Yes

    • @TarenGarond
      @TarenGarond 25 дней назад

      The enrichment would also happen in constant RPM situations(Or even with (non-extreme) RPM drops) too, the enrichment happens because the piston lags behind the airflow increase from opening the throttle.

  • @Hipyon
    @Hipyon 28 дней назад

    Nice one Constant depression carburettors are beautiful things And you mentioned the importance of the crankcase ventilation👍 it is positively dangerous to disconnect it Carbon monoxide isn't friendly

    • @ACDodd
      @ACDodd  28 дней назад

      I would not say it was dangerous but it’s most definitely not healthy for you.

  • @mr.buttons8486
    @mr.buttons8486 28 дней назад

    Thank you very much Sir🙏

  • @demiquadfpv3333
    @demiquadfpv3333 28 дней назад +1

    Great video, one of the most confusing things learning when a piston flys up (thin oil etc) it leans, which I'll admit was not what I used to think due to thinking the needle was pulling out and therefore must be enriching. As a side request you once did a videos with a weight (lay shaft I think) to show approximately the drop speed on a carb, would you be able to show that test on this hs4 please?

    • @ACDodd
      @ACDodd  28 дней назад

      Use the same test. It’s only starting point, and still maybe miles out for your actual car.

  • @MiniMattTV
    @MiniMattTV 23 дня назад +1

    Will connecting a crankcase breather to the carb affect the mixture in the engine?

    • @ACDodd
      @ACDodd  23 дня назад

      No, because the carb is calibrated with it fitted.

  • @deancook2377
    @deancook2377 28 дней назад +1

    Thank you for the presentation; do you use the wax jets on twin HS2's as well?

    • @ACDodd
      @ACDodd  28 дней назад +2

      That’s a good question, and no is the answer

  • @Slack3rDav3
    @Slack3rDav3 23 дня назад

    a good thing to show would be the different jets available for each carb. fixed jets come in rebuild kits, so do you piecemeal a rebuild kit? And do you use the waxstat jets for all HS carbs?

    • @ACDodd
      @ACDodd  23 дня назад

      No both jet types are available in rebuild kits, as are the exact rebuild kits I use for the carbs I rebuild, CRK121A for the HS4 carbs

  • @allegrogt1
    @allegrogt1 27 дней назад

    Thank you AC for this new episode on explaining SU carbs👍👍
    I’m a little bit confused on
    why ported vacuum gives better emissions on idle.
    I already read a lot about this
    but don’t see the benefit.
    My 1275 is fitted with a 123 dizzy
    and the recommendation is to run this dizzy with ported vacuum.
    I’m a little bit unsure.
    What are your thoughts on this
    Thank you 🙏

    • @flapjck1
      @flapjck1 27 дней назад

      when engine idle - set AFR 14.6 ( lambda 1 ) - very good emission, for higher revs you have correction by vacuum and for HIGH revs mechanical correction by ignition system ( distributor )

    • @ACDodd
      @ACDodd  27 дней назад +1

      Nothing to be confused about too much vacuum advance at idle causes incomplete combustion, and therefore higher HC emissions.

    • @allegrogt1
      @allegrogt1 27 дней назад

      @@ACDodd thank you
      got it now 👍👍

  • @grahaminaus
    @grahaminaus 27 дней назад

    Great video AC, and happy birthday too.... Question.... why did the factory opt for manifold vacuum signal over behind throttle blade? Or is this just your performance improvement to only bring in vacuum advance quickly as throttle is opened....??

    • @ACDodd
      @ACDodd  27 дней назад +2

      I will cover this at the begining of the next video.

  • @martinhibbert1428
    @martinhibbert1428 28 дней назад +2

    Does the float chamber need to be mounted with a rubber mount between it and the carb body ? I was always under the impression that if they were mounted solidly then vibration could cause problems with the fuel supply.

    • @ACDodd
      @ACDodd  28 дней назад +1

      Only rubber mounted on the twin carb models, can’t say I have ever seen an issue on the single carb applications using a solid mount.

    • @martinhibbert1428
      @martinhibbert1428 28 дней назад

      @ That’s interesting, never knew that. Both my cars are twin carbs and it’s 30+ years since I have owned a mini so don’t recall how the float chamber was mounted.

  • @fazorboy
    @fazorboy 27 дней назад +1

    Hey teacher, how long till the next lesson? And i wish my pistons in the bell housing were that strong

    • @ACDodd
      @ACDodd  27 дней назад +1

      Filming part 2 today.

  • @kathysarmcandy1992
    @kathysarmcandy1992 28 дней назад +1

    You do do some pretty units. Is that some satin clean on the body?

    • @ACDodd
      @ACDodd  28 дней назад

      No.

    • @kathysarmcandy1992
      @kathysarmcandy1992 28 дней назад +1

      @@ACDodd I was kidding. 🤟 Are you using a tumbling media for body cleaning?

    • @ACDodd
      @ACDodd  28 дней назад

      @ no tumbling

  • @stuwhite2337
    @stuwhite2337 28 дней назад +1

    Do you prefer hs or hif as a general rule?

    • @ACDodd
      @ACDodd  28 дней назад +1

      HIF is a better carb full stop.

    • @stuwhite2337
      @stuwhite2337 28 дней назад +1

      @ACDodd Thanks. From what I read a lot of people seem to want to swap from HIF to HS, at least on MGBs.