my v4, How to make oil scraper ring?

Discussion in 'A Work In Progress' started by sition, Jan 27, 2019.

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  1. Jan 27, 2019 #1

    sition

    sition

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    My V4 is 3.5cc. How can I make a scraper ring? Smoking is really annoying.

    Sorry I can't publish piston pictures.
     
  2. Jan 27, 2019 #2

    sition

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    I'm making a V4 engine. It works at 90 degrees.
     
  3. Jan 27, 2019 #3

    sition

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    I made an oil pump and sprayed the lubricant onto the crankshaft for splash lubrication.
     
  4. Jan 27, 2019 #4

    Cogsy

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    What are the dimensions of your piston? I'm building a ~10cc V4 and I thought that was getting pretty small, 3.5cc sounds very tiny. How many rings per cylinder do you have at the moment?
     
  5. Jan 27, 2019 #5

    sition

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    Single cylinder 3.5cc total 3.5*4

    Two rings at present
     
  6. Jan 27, 2019 #6

    Cogsy

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    Ahh, about the same size then. Maybe you could add a third ring below the gudgeon/wrist pin but possibly you are overwhelming your rings with oil. The V4 I'm building uses a dipper on the bottom of each conrod for simple splash lubrication. I can't say on my model as it's not finished, but I have not seen a smoking issue with other peoples' builds of the same engine. Maybe try reducing the amount of oil spraying onto the crank.
     
  7. Jan 27, 2019 #7

    Hopper

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    As well as reducing oil supply, you could look at putting on a crankcase breather with reed valve so crankcase pressure can escape but air can not be sucked back in.
     
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  8. Jan 27, 2019 #8

    sition

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    I tried to reduce it, but the cylinder on the left has almost no lubricant, and the cylinder on the right has normal lubricant. If a ring is added, will the resistance be greater? The displacement of 3.5CC is uncertain whether these resistance can be overcome well. Thank you very much
     
  9. Jan 27, 2019 #9

    sition

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    When there is no spark plug, turn the crankshaft and the ventilator has no gas. When there is a spark plug, the gas is blown out. Are these gases leaking from the piston? Is there no negative pressure in the ventilator? Thank you
     
  10. Jan 27, 2019 #10

    WOB

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    It sounds like excessive ring leakage to me. That will cause crankcase pressure as well as oil burning. I suspect your rings are not sealing well. I'm guessing your bore dia. is between 1 and 1.5 cm. Making rings that seal well at that small size is very difficult. I would suggest lapped pistons rather than rings as a cure.

    WOB
     
  11. Jan 28, 2019 #11

    sition

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    O-ring Seal Is it suitable for high speed?

    Thank you
     
  12. Jan 28, 2019 #12

    editor123

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    No, they will melt.
     
  13. Jan 29, 2019 #13

    Cogsy

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    I believe the Tiny inline 4 uses o-rings as piston rings successfully. Your bores are going to need to be super smooth though.
     
  14. Jan 29, 2019 #14

    sition

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    Nice, thank you. What is the maximum speed?
     
  15. Jan 30, 2019 #15

    Cogsy

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    The Tiny inline 4 revs to very high RPM but I don't know the surface speed of the orings.

     
  16. Jan 30, 2019 #16

    necowboy

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    Heavy oil consumption can also be caused by a lack of valve seals, particularly on the exhaust valve.
    Exhaust gases rushing past the valve guide cause a low pressure around the valve guide.
     
  17. Jan 31, 2019 #17

    sition

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    Are there any running videos? Thank you
     
  18. Jan 31, 2019 #18

    sition

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    Yes, I didn't make valve oil seals. The valves are very small. What can you do to make such small valve seals?
     
  19. Jan 31, 2019 #19

    Cogsy

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    I don't get what you mean - it is running in that video. If you search 'Tiny Inline 4' on Youtube you should get plenty of other videos.
     
  20. Jan 31, 2019 #20

    sition

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    Good. Have you tried to run for a long time? Great L4
     

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