My first engine

Discussion in 'General Engine Discussion' started by Ross_macker, Dec 30, 2008.

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  1. Dec 30, 2008 #1

    Ross_macker

    Ross_macker

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    Hi all,

    i have just started my first ever engine and i am not too sure about my model. I decided to build the Elmers Wobble Plate motor. I have made the base, colums, bushes, wobble plate, crank shaft (including crank plate), and fly wheel. I have been assembling as i go and have noticed that when i spin the fly wheel it only turns a couple of turns then stops. i have oiled the bushes. just wondering how freely it should all turn ???

    any help would be much apreciated.
    thanks
    ross
     
  2. Dec 30, 2008 #2

    tel

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    Sight unseen. I'd say you have done very well to get it to spin that much - running it under power will free things up considerably
     
  3. Dec 30, 2008 #3

    b.lindsey

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    Hi Ross,
    Elmer's Wobble Plate is a nice little engine. After years of running mine, I doubt it spins more than a couple of revs just by turning the flywheel, but it runs very well on 4-5 psi. As long as you don't feel any binding as you turn it over by hand, you should be in fine shape and it will only get better with some runnning time on it. I case you haven't noticed yet, this group loves pictures!! Hope you will post some of your first project.

    Bill
     
  4. Dec 30, 2008 #4

    mklotz

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    Bob is correct. As long as there is no binding, it's more or less impossible to relate how often it turns to eventual engine performance.

    Mine has a solid steel flywheel and, with a reasonable flick, will turn over a few times but that doesn't mean much in the greater scheme of things.

    Go ahead and finish it and test run it. That's where the satisfaction lies. If you're still unhappy with its performance at that stage, look to the fit of the wobble arm on the wobble plate. That's the place where most of the problems will lie. I recommend a light grease rather than oil on the wobble plate.
     
  5. Dec 31, 2008 #5

    Ross_macker

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    Hi,
    Thanks. just wanted to know that i was on the right track. i am only 25 and have not done that much machining yet....

    anyways here are some pics....
    [​IMG]
    [​IMG]

    hope it works
    thanks
     
  6. Dec 31, 2008 #6

    cfellows

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    Gonna be a nice engine. Unfortunately, you can't see the posted pictures unless you have a login to facebook.

    Chuck
     
  7. Dec 31, 2008 #7

    Ross_macker

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    hi all,

    ha ha that fixed it. ;D

    btw it is twice the size of the plans as i don't normly work with things this small.

    thanks
    ross
     
  8. Dec 31, 2008 #8

    Maryak

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    You too [​IMG]

    Coming along very nicely.

    Best Regards
    Bob
     
  9. Dec 31, 2008 #9

    stevehuckss396

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    Nice job! I love these air engines and Elmer is the king.

    I'm just the opposite, I tend to go smaller and smaller.

    Steve
     
  10. Jan 2, 2009 #10

    Ross_macker

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    hi all,

    What is the best way to go about finishing the bore and piston ??? Just the machined finish would not be good enough. I thought about using a brake cylinder hone ??? I had to make the cylinder out of aluminium as i could not find any brass to make it out of.

    thanks
    ross
     
  11. Jan 2, 2009 #11

    Brian Rupnow

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    That doesn't look like a wobble plate engine to me. It looks like a wobbler which is something entirely different. An aluminum piston in an aluminum cylinder won't work too well---the two similar metals will "gall" and seize up. Should be an aluminum piston in a brass cylinder or vice versa. As far as finishing--Use a reamer to create the cylinder bore, then turn the piston to size using conventional lathe tools, for a "snug" fit. Use some plain white toothpaste for a lapping compound, and slide the piston in and out of the bore by hand untill it loosens up. These air engines are not terribly demanding of a real precision fit. Better to have it a bit loose and add a couple of drops of 30 wt. oil to the bore---it will seal the piston and act as a lubricant.---Brian
     
  12. Jan 2, 2009 #12

    b.lindsey

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    Well, Brian beat me to what i was going to add...a reamed bore done with a good sharp reamer is sufficient assuming you have a reamer the correct size. Most of Elmers designs used common sizes for bores, pistons, etc. Elmer does call it a wobble plate engine Brian...with the addition of a few more parts it should become clearer. Here is a picture that may help.

    Bill

    [​IMG]
     
  13. Jan 2, 2009 #13

    Brian Rupnow

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    Thanks Wlindii--I see the error of my ways. When I hear "wobble plate", my mind jumps to "swash plate". I guess that its not a common wobbler, as I had thought. the "wobble plate" controls the valving.---Thanks.
     
  14. Jan 2, 2009 #14

    Philjoe5

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    Nice work Ross. :bow: You've done a lot more machining than I did when I was 25 so congratulations and great success in your future projects.

    Cheers,
    Phil
     
  15. Jan 2, 2009 #15

    Ross_macker

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    thanks, i will have to see if i can get hold of a reamer. i have just started out and dont have much tooling. The cylinder is made from aluminium but the piston is still brass. Is there any other way of doing it without the reamer???

    Thanks for the pic Bill. I have not been able to find a decent pic of one finished. :bow: now i know what i am aiming for.

    thanks
    ross
     
  16. Jan 3, 2009 #16

    Divided He ad

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    Hi Ross,

    You beat me to my next type of engine build...They look really good to me :)
    I meant to have started it last year!! Now more like this summer!

    Anyway... It looks like it's progressing nicely.

    The cylinder can be done very effectively and cleanly with what is called a 'D' bit....Gives a smooth finish and can shape the bottom of the cylinder too (Some I've seen are made with rounded ends) You can get these cheaply enough from some engineering supply company's. Mostly in imperial sizes (don't know where you are?) so the metric heads might have to make the piston to the plan size... I convert all my builds to the nearest metric ;D

    Idea is that you use a drill to get the hole just under the 'D' bit size then use it as a kind of reamer to open the bore smoothly to size.
    (Good enough for Boggie, good enough for me!)


    I would assume that in aluminium you would need to use a lubricant of sorts whilst drilling (both with twist drill and 'D' bit)

    I'm sure some of the older knowledgeable guys will shout up if I'm wrong!?


    But that's how I would go about it. Since I don't have too many reamers either ;D


    Good luck, I hope to see it running soon... But probably no where near as much as you do ;)



    Ralph.


     
  17. Jan 9, 2009 #17

    Ross_macker

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    hi all,

    finally got around to getting some more done. have the cylinder and head done and have finished con rod..... no piston yet. that should be tomorrows job...
    [​IMG]
     
  18. Jan 10, 2009 #18

    Divided He ad

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    Looking good Ross ;D

    How did you do the cylinder in the end?


    Now just a few fiddly bits and you should have a nice little engine ;)



    Waiting for the video :D


    Ralph.
     
  19. Jan 10, 2009 #19

    Ross_macker

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    hi, i ended up just using the hone. i got the best finish i could on the lathe then machined the piston and honed the bore till the piston was a nice smooth sliding fit. i put a few drops of oil on the bore and it all still turns over nicely....
     
  20. Jan 10, 2009 #20

    b.lindsey

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    That is looking very nice R_m. Looking forward to a video as well.

    Bill
     

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