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  1. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hi, gruntguru. Yes, engine speed control under variable load is supposedly done by a throttle. Something like that was installed, but I´m not sure if it was properly built.
  2. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hello! Here I come back to update you all about the converted engine. Nowaday, it is operating pretty well, according costumer´s words. It was achieve only after some important corrections that have took a lot of day until they were finally done. In order to save your precious time, specially...
  3. sraposo

    Camshaft specs for Scania trucks model xx112 and xx113

    Hi, CWB1. I´ve been spending my time since today morning but only now I´ve got a DN11/DS11 manual in spanish. To whom it may interest, visit https://en.manualesdemecanica.com/manuales/func-startdown/677/
  4. sraposo

    Camshaft specs for Scania trucks model xx112 and xx113

    Sirs, Does anyone have specs of Scania camshafts used on trucks models xx112 and xx113? Regards, Sergio
  5. sraposo

    What´s maximum static compression ratio appliable to LPG?

    enginesrus, Not yet. At present moment engine is being rebuilt and it´s expected that it will work tomorrow morning. CR now is 11:1, which will not cause problem with natural aspiration, since there are aspired engines that run on 93 octane gasoline with CR 13:1. As LPG has 110..112 octane...
  6. sraposo

    What´s maximum static compression ratio appliable to LPG?

    gruntguru, Although I´m not graduated in Mechanics (I´m MSc in Electronics and BSc in Computer Science, but a long time developing products for ICE), I clearly see your comments. A good product is not a twist of fate. There´s a difference, maybe huge, between an engine working as efficiently as...
  7. sraposo

    What´s maximum static compression ratio appliable to LPG?

    enginesrus, At the time that video was shot, the only known (potencial) issue was (apparently, but probable) excessive CR. No comments about spark plug pipes, too narrow spark plugs electrodes gap, improper fuel controlling had been told. Ignition system was the first to be put under...
  8. sraposo

    What´s maximum static compression ratio appliable to LPG?

    hemi, Good engineering is for (preferably) good engineers with proper resources (money, time and knowledge of target application). When at least one of these factor is missing, good engineering is not the expected result. It´s reasonable that a supplier, specially if a maker, provides...
  9. sraposo

    What´s maximum static compression ratio appliable to LPG?

    BrianPetersen, Costumer owns equipment for machining parts. They reduced CR by removing material from piston top,measuring new concavity volume and calculating PMS/PMI volumes ratio. It took a couple of hours.
  10. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hi, NickJ67. Well, this thread became interesting in a unorthodox way... it was only intended to discover (not yet achieved) what´s the practical maximum CR for LPG, but due several surprising discoveries not all told here and not always fully related, it turned into a thrilling story. One...
  11. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Sirs, My original intention was to know the practical maximum CR for LPG because of what seemed to me something related to pre-detonation. At that time, costumer suspect that ignition system was mistaking ignition order and/or varying erroneously ignition timing, what was proven not to be true...
  12. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hi, Brian. You´ve taken your time to detail the probable gases dynamics in the pipe and I agree with you. That´s what I´ve thought when I was told about this weird plug mounting. Probably, the tubes were not thermally considered and I don´t know what metal was employed. So they are exposed to...
  13. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Brian, I´ve just received information that spark plug nose is 85mm far from chamber surface. Plug was threaded in a tube and its opposite extremity is screwed on engine head...
  14. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hemi, Yes, your considerations on a not chaotic engine operation under pre-ignition due over compression are sensible, but the fact that altering spark ignition timing made no change on engine behavior raises a suspicion that something is starting ignition before sparks. Do you also think so...
  15. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Brian, LOL! No, I've NOT invented a HCCI! So, if changing (a lot) spark ignition timing makes no difference on engine behavior, it´s not (totally) wrong to think that something else is igniting fuel. YES! I still consider that spark plug gap may be exceeding ignition system output capability...
  16. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hi! I´ve found two papers that reinforce suspicion that 16:1 CR may explain this malfunctioning: 1) "A DIESEL ENGINE CONVERTED INTO OTTO CYCLE ENGINE: THE INFLUENCE OF THE SPARK ADVANCE ON ITS PERFORMANCE AND ON NOX EMISSIONS" http://servidor.demec.ufpr.br/reterm/ed_ant/20/artigos/252-2012.pdf...
  17. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Brian, "Does your ignition system provide enough spark energy with such high compression?" Me > The model that is being used provides up to 45kV. I also think that spark plug gap of 0.8mm may be excessive for such compression ratio. Several A/F ratio were experimented but failure persists.
  18. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Video showing engine malfunction. https://files.engineering.com/download.aspx?folder=77c16797-55cf-47ad-b6ec-c27d5ebb1922&file=VID-20180817-WA0025.mp4
  19. sraposo

    What´s maximum static compression ratio appliable to LPG?

    Hi, BrianPetersen. Below, comments on your remarks. "Backfiring through the intake or out the exhaust isn't a compression-ratio-related issue." Me > Sure, CR has nothing to do with those blows. CR was mentioned because it is potentially an issue to cause knocking. Since present malfunctioning...
  20. sraposo

    What´s maximum static compression ratio appliable to LPG?

    enginesrus, What trigger the system depends on version of product. There´s version that employs a pair vr sensor-magnet and version that uses an inductive proximity sensor to detect either an unique lobe or notch on pulley crankshaft or fly-wheel. Optionally, a disc/gear fixed on camshaft or to...

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