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Thread: flathead issues!!!

  1. #1
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    flathead issues!!!

    ok new problems for me . building gold plate flatheads for my son after race have 4oz of oil in catch can. motor is fresh .003 piston to cylinder clearence. top ring .002 ,2nd .004 oil ring .008. new breather running it at 6200 rpm. not sure what is going on . changed breather with new one with hole drilled in bottom to help drain oil back. feel like it has to be the breather but new one didn't help. any thoughts.


    other engine has same specs but this one keeps pushing oil by the breather gasket. same thing change breather out. seal the gasket and after race engine covered in oil runs by breather gasket gets sucked in flywheel and blows it all over engine. at the end of my rope.

  2. #2
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    Are you sure it's not the flywheel side oil seal?

    You said you've already changed the breather to a new one, so we'll rule that out.
    Is your catch can breathing sufficiently? (ie filter and/or line not plugged)
    Pushing the breather line too deep into the breather grommet? Breather grommet cracked or leaking?

    Any chance that you got the rings out of order or upside down?



    -----
    Thanks and God bless,
    Brian Carlson
    Carlson Racing Engines
    Vector Cutz

    www.CarlsonMotorsports.com
    Carlson Motorsports on FaceBook
    29 years of service to the karting industry
    Linden, IN
    765-339-4407
    bcarlson@CarlsonMotorsports.com

  3. #3
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    [QUOTE=CarlsonMotorsports;734322]
    Any chance that you got the rings out of order or upside down?

    X2. If an engine is "Blowing Oil" it has a problem in the cylinder ! Some R3 pistons have had a "blemish" on the bottom of the top ring land that caused cylinder pressure leakage under the top ring. Too much rod bearing or wrist pin clearance will cause "Ring Flutter" at high RPM creating crankcase pressure. Excessive cylinder to wall clearance too,, but your .003" should be fine. IMHO .002" top gap could butt during initial run up and cause excessive gap after only one race night. I like .004",, just me. A well prepared cylinder with a ground top ring assembled with .004" top gap will only have .006" after 500 laps if taken care of properly. Gap for the top ring is necessary for gas pressure to load the ring against the cylinder wall. So don't over think this "tight gap" deal.

    Best, WP

  4. #4
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    2 Questions:

    1. How much oil are you running?
    2. Is the kart tight?

    Too much oil, and/or a tight kart will push oil out like there is a hole in the block
    ---------------------------------------------------------
    The Weapons - 2008 Mongoose Champ, 2004 PRC Phenom JPM Indoor Edition
    The Ammo - GKS Flathead, GKS Animal
    The Sidearm - 2006 PRC Phenom

    "We claw with our finger nails for that inch. Because we know, when we add up all those inches, that's going to make the difference between winning and losing..."

  5. #5
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    14 oz off oil. kart is a little lose if anything.

  6. #6
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    thanks brian i will check all things you have suggested

  7. #7
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    Quote Originally Posted by hawkeye1734 View Post
    14 oz off oil. kart is a little lose if anything.
    Have you ever tried running 12OZ?

    We run 12 OZ in all of our stuff...some of our engines, if we got anything over 12OZ, would puke oil big time.
    ---------------------------------------------------------
    The Weapons - 2008 Mongoose Champ, 2004 PRC Phenom JPM Indoor Edition
    The Ammo - GKS Flathead, GKS Animal
    The Sidearm - 2006 PRC Phenom

    "We claw with our finger nails for that inch. Because we know, when we add up all those inches, that's going to make the difference between winning and losing..."

  8. #8
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    never tried but i will thanks

  9. #9
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    14 ounces on a 7,8, or 15* mount.
    12 ounces on a 5* or flat mount for us.

    Personally, I like tight ring end gaps...but you've got to start with a perfectly prepared cylinder (ie square with no taper and plateau finished,) then there is a knack to low tension rings and getting the rings to fit the ring groove correctly...they are certainly not plug-n-play when you get them. You're second and oil ring gaps are considerably tighter than I tend to run, but they are larger than the top ring (which is good so that it doesn't trap cylinder pressure and cause ring flutter at high rpm.)

    Even if it were overfilled with oil, it should only push out the excess oil, not clear down to a couple ounces left in the crankcase.
    You've got cylinder pressure in the crankcase (either not enough ventilation, or pressure getting past the piston/rings.)
    You need to fix the problem -- it will only get worse.

  10. #10
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    i have made a fixture to detension 2nd ring.and also lap rings. i have been using dyno cam rings 1st and 2nd and either burris or briggs oil rings. cylinder is honed with deck plate on using sunnen jr hone. followed by 600 grit brush hone. to the best of my measuring abilitys cylinder is round and strait (no taper)not sure if there is any suggestions as to wether my procedure is correct or not. feel like im doing something wrong lol

  11. #11
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    If you lap the rings too much you'll get ring float. What is you ring side clearance?

  12. #12
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    Lapping the face or lapping the flats?
    What's your cleaning procedure ?

  13. #13
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    Do you have a leak down tester ? A leak down test will tell a lot.

    Best, WP

  14. #14
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    .002 side gap. I clean using ultrasonic cleaner. Lap the flats of rings

  15. #15
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    Is the piston hitting the head ? That will cause ring flutter,,, among other things.

    WP

  16. #16
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    Quote Originally Posted by hawkeye1734 View Post
    i have made a fixture to detension 2nd ring.and also lap rings. i have been using dyno cam rings 1st and 2nd and either burris or briggs oil rings. cylinder is honed with deck plate on using sunnen jr hone. followed by 600 grit brush hone. to the best of my measuring abilitys cylinder is round and strait (no taper)not sure if there is any suggestions as to wether my procedure is correct or not. feel like im doing something wrong lol
    Deleted
    Last edited by Marcis71; 09-19-2018 at 04:16 PM. Reason: "Cause I didn't pay close enough attention

  17. #17
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    no piston is not hitting head

  18. #18
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    Leak test

  19. #19
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    Quote Originally Posted by hawkeye1734 View Post
    .002 side gap. I clean using ultrasonic cleaner. Lap the flats of rings
    I'M old school and like hot soapy water.
    Leak test.

  20. #20
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    I have had a few like that that I fixed by replacing the gasket between the breather halves.

  21. #21
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    Any update on what you found to be the cause?

    Another thing I thought of was a crack in the block, or someone backfaced the IN valve spring pocket too deep and it's leaking through there. Seen both, and fixed both with some good epoxy. Look very closely around the lower right of the breather gasket surface on the block for a crack...also behind the right side bolt (behind the IN spring pocket) where the casting is thin and can break through from an over-zealous spring relief cut.

    You should be able to see where the oil is coming from (ie source) by where it is still wet and clean. The dust will stick and accumulate where the oil isn't running as fast.

    Hopefully you already got it figured out by now though -- season is quickly winding down.

  22. #22
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    thanks brian i will check that out. i stopped using those two engines. going to look at them over the winter. was wondering if anybody drills hole in bottom off new style breathers with small hole.seems like older breathers where better.never seemed to have problems with them

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