1936 midget engine

Discussion in 'Engines From Castings' started by whitehouse260, Jan 18, 2018.

Help Support HMEM by donating using the link above.
  1. Jan 18, 2018 #1

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    I recently purchased a midget gas engine built from plans in the 1936 popular mechanics magazine. My question is does this design call for a hollow crank shaft? Has anyone ever heard of a hollow crankshaft? When I say hollow I mean you can see all the way through. I will try to get a picture of it soon.
    Thanks,
    Matt
     
  2. Jan 19, 2018 #2

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    Here are some pictures, the crank looks like it was made aas 2 halves I'm thinking I will press/solder a pin into the hole in the crank pin on onside to help with alignment and hopefully to keep it from binding up.

    IMG_20180118_185248.jpg

    IMG_20180118_185242.jpg
     
  3. Jan 19, 2018 #3

    stevehuckss396

    stevehuckss396

    stevehuckss396

    Senior Member HMEM Supporter

    Joined:
    Nov 19, 2008
    Messages:
    3,812
    Likes Received:
    901
    Gender:
    Male
    Occupation:
    Construction
    Location:
    Sterling Heights, MI
    hollow crank wouldn't surprise me.

    Is the plan to repair and restore? what condition is the engine in?
     
  4. Jan 19, 2018 #4

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    I guess the plan for the moment is to repair, will the hollow crank affect it running? The auction came with a half finished crank, I'm not sure why he stopped maching it. it's not bent but I'm away from my my machines to finish the crank.
     
    Aerostar55 likes this.
  5. Jan 19, 2018 #5

    Hopper

    Hopper

    Hopper

    Well-Known Member

    Joined:
    Feb 19, 2013
    Messages:
    574
    Likes Received:
    186
    Your crank looks completely different from the original drawings seen here https://books.google.com.au/books?id=otsDAAAAMBAJ&pg=PA1349&source=gbs_toc&cad=2#v=onepage&q&f=false
    page 787 onwards in PM Nov. 1936.
    Maybe someone was making their own version from several pieces instead of the original casting. The hole up the middle would be for alignment in assembly as you say. If left unplugged, the crankcase will breathe in and out through the hole on each stroke, which could get kinda messy!

    Those old magazines are great reading. Whole different world back then. And so much more content than magazines today. People actually got a month's worth of reading in each issue!
     
  6. Jan 20, 2018 #6

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    more pictures incoming... the guy who built it made the head out of brazed together scrap steel only problem is he didn't leave enough room to tighten the plug lol

    IMG_20180120_122601.jpg
     
  7. Jan 20, 2018 #7

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    one question i have though is will the 2 half crank really matter that much??? there are many designs of engine that have an overhung crank on a bearing so will having 2 of those joined in the conrod big end hurt? also the connecting rod is brazed together when im home for spring break i will probably make a new on my cnc mill along with finishing the original crank.
     
  8. Jan 22, 2018 #8

    Hopper

    Hopper

    Hopper

    Well-Known Member

    Joined:
    Feb 19, 2013
    Messages:
    574
    Likes Received:
    186
    Looks like a nice little engine and worth persevering with.

    I should think the two piece crank would work OK. Seems to be done on plenty of other model engines. Silver solder should stand up to the rigors of demonstration running etc.

    I'm sure I've seen somewhere drawings for a four stroke with an overhung crankshaft, with an extension on the crankpin driving another overhung crankshaft half that delivers drive to the timing gears. Saves having to get perfect crank alignment I guess.
     
    whitehouse260 and Aerostar55 like this.
  9. Jan 22, 2018 #9

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    Ok thanks for the advice!
     
  10. Jan 24, 2018 #10

    ddmckee54

    ddmckee54

    ddmckee54

    Well-Known Member

    Joined:
    Jul 8, 2009
    Messages:
    157
    Likes Received:
    18
    Most vintage model engines, 2 strokes anyway, had hollow cranks. I see that this is a 4 stroke, maybe this engine was built from parts of other engines?

    Don
     
  11. Feb 17, 2018 #11

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
     
  12. Feb 17, 2018 #12

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    Where did you get it? These engines turn up on ebay or model engine shows from time to time. I know of about 5 that I have seen over the past 4 years or so. They do run pretty good.
     
  13. Feb 18, 2018 #13

    whitehouse260

    whitehouse260

    whitehouse260

    Member

    Joined:
    May 26, 2016
    Messages:
    12
    Likes Received:
    1
    It came from ebay. The seller included the patterns and a casting kit for the wall water witch.
     
  14. Feb 19, 2018 #14

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    What needs to be done in order to get it running?
     
  15. Feb 21, 2018 #15

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    You have additional castings for the Wall
    Water Witch?
     
  16. Feb 21, 2018 #16

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    I have drawings for the Midget engine that were
    Published in Popular Mechanics
     
  17. Aug 7, 2018 #17

    rockets

    rockets

    rockets

    Well-Known Member

    Joined:
    Jan 1, 2010
    Messages:
    69
    Likes Received:
    12
    Gender:
    Male
    Occupation:
    Aircraft Engineer
    Location:
    South Oxfordshire UK
    "I'm sure I've seen somewhere drawings for a four stroke with an overhung crankshaft, with an extension on the crankpin driving another overhung crankshaft half that delivers drive to the timing gears. Saves having to get perfect crank alignment I guess"

    ET Westbury's Whippet is designed in this fashion.

    Regards,
    Rockets
     
  18. Aug 16, 2018 #18

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    I have the original drawings for the Midget engine that you have. Do you plan on building the Wall Water Witch engine from that auction?
     
  19. Sep 13, 2018 #19

    Aerostar55

    Aerostar55

    Aerostar55

    Active Member

    Joined:
    Feb 27, 2014
    Messages:
    25
    Likes Received:
    7
    The Wall Water Witch is my favorite little engine. I have original drawings for it. I also have the original
    drawings and magazine article for the Midget engine that you bought. Maybe we could do some sort of a trade? I can help you with parts or information on that Midget engine.
     
  20. Sep 14, 2018 #20

    Bob44

    Bob44

    Bob44

    New Member

    Joined:
    Oct 29, 2010
    Messages:
    2
    Likes Received:
    0
    Gender:
    Male
    Occupation:
    None
    Location:
    Nolanville, TX
    I think it's called a follower crankshaft. A couple engines in the Home Shop Machinist magazine uses them including the Rupnow 4 cycle. I had my doubts about it but it works fine.
    Also 2 cycle model air engines with rotary intake valve use a hollow crank.
    Just my .2 cents for what it's worth.
     

Share This Page