Making of the 10HP Diesel Prime Mover

Discussion in 'Some Assembly Required' started by danielson, Jul 11, 2010.

  1. Sibbo

    Sibbo Been here awhile

    Joined:
    Sep 23, 2009
    Oddometer:
    359
    Location:
    Tweed Valley , Northern NSW
    It looks as though I might have a solution to the various problems .i've come up with an older donor bike , a1964 model Enfield .The rego boys aren't interested in anything that old... do what you like he said !

  2. Lambo

    Lambo Been here awhile

    Joined:
    Aug 30, 2006
    Oddometer:
    730
    Location:
    Seattle
    Great build, I really like the no nonsense approach and the good craftmanship. I have a question about cooling. Seems like the flywheel fan is redundant as the bike will generally move through the air to cool itself. Is there a big difference in the fins or surface area on these diesels compared to a standard air cooled thumper? Could you lose some weight and parisitic power loss by removing the shroud and fan assembly or do you feel like it is really necessary to have the fan in place?

    Watching with gret interest, RE's are a bit dear here right now but I have an eye out.

    Thanks,
  3. Sibbo

    Sibbo Been here awhile

    Joined:
    Sep 23, 2009
    Oddometer:
    359
    Location:
    Tweed Valley , Northern NSW
    You may be right about that but interestingly no one seems to take the fan housings off. I've seen photos of dozens and they are all as they come from the factory .There may be a lesson there .

    I've seen a couple of photos of older British diesels one bikes without the fans but none of the Chinese , Hatz or other modern ones .

    On the other hand it may contribute to quietening the engine a bit and would make a very complete aerodynamic fairing possible without worrying about engine overheating .
  4. P B G

    P B G Long timer

    Joined:
    Mar 7, 2008
    Oddometer:
    10,001
    Location:
    Greater Chicago
    I am not sure about that theory.

    Two things I would want to know, how much air flow the fan makes when the engine is running vs how much air is flowing when the bike is moving through the air.

    And then simply, the fan draws air across the engine in a specific direction, usually through a shroud, the engine is turned 90 degrees off from this direction of airflow, and then blocked by the tire, fender etc.

    In terms of parasitic loss, it is probably worth having this loss in comparison to the need to keep the bike moving at all times.
  5. snoopy

    snoopy Been here awhile

    Joined:
    Nov 18, 2005
    Oddometer:
    265
    Location:
    Newcastle UK
    The flywheel is needed to keep the engine turning over. The weight of the fins on it is negligible. :wave