Rob/Sub EH035 & "automatic timing adjustment"

Discussion in '4-Stroke Engines' started by sparky, Jul 12, 2008.

  1. sparky

    sparky Active Member

    What does it mean? This doesn't mean "no valve adjustments", right?? ... or does it?

  2. duivendyk

    duivendyk Guest

    Usually this means that the ignition timing is advanced with increasing rpm.This is done because it takes a certain time for the micture to ignite&burn, with higher rpm there is less time for this, so advancing the ignition will generate more power.Too much advance can lead to high stresses on the piston and is dangerous.Valve timing is usually fixed,but in sophisticated high performance engines, the valve timing is changed at high rpm to get better cylinder filling and improved engine breathing for
    increased power.
  3. sparky

    sparky Active Member

    So valve adjustments will still need to be made then?

    Either way... I'm REALLY liking what I read about this engine. I actually just got one in the mail two days ago, but the "inner" part of the plastic airbox, where the choke lever is, was broken into 6 pieces. So, I'm gonna have to wait another week or two to get 'er runnin'. :mad: :mad: :cry:
  4. Nuttsy

    Nuttsy Member

    Ooooh, Bummer! Bad news about the breakage. :mad:

    Yes, you will still need to adj. the valves in time, but not a big deal. 2 gaskets are all thats needed in the parts department and a few minutes of time. Simple job.
  5. graucho

    graucho Active Member

    Good question, maybe this answers a question of mine also. In my hydrogen experiments I can run a 2.5 hp Lifan with the timing retarded with full throttle range. I couldn't get it to run without this change. (timing retarded)

    Then, I do the same with my Rob/Sub EHO35 and I can get it to run with gas or hydrogen the same without changing the timing. This now leads me to believe that maybe the automatic timing adjusts to compensate for fuel grades/loads/elevations/altitude/rpm etc... Hummm, Ill have to keep an eye on this thread. I'll see if I can get a reply by e-mailing the manufacturer. Thanks sparky for stimulating my brain. :grin:
    Last edited: Jul 12, 2008
  6. sparky

    sparky Active Member

    I had called to ask them a couple questions the other day, but my first one was...

    How do you adjust fuel/air mixture?

    He said, "You don't!" I said, "Whu??? What if I'm at a very high altitude?" He said, "We have different sized jets."

    I thought that was pretty odd, but it sounds too cool. It's even cooler that it works with hydrogen a lot easier than other motors.

    Anyway, who lives thousands of miles up and has an EH035?? Did you have to change your jets? My guess is no.
  7. duivendyk

    duivendyk Guest

    I would deem that rather unlikely.This engine has no engine management system,all it has is a breakerless magneto,you could in principle engineer a spark advance system with what info &power you get from the flywheel,it would be a pretty complex chip,but there are a lot of engines that could use it too.Different fuels have different flame propagation velocities which affect optimum ignition timing,no doubt about that.