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Author Topic: Kohler 250 liquid piston question  (Read 2209 times)

gspaulding

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Re: Kohler 250 liquid piston question
« Reply #15 on: March 09, 2017, 11:35:45 PM »
Hello alongtimeriding
Rings are very complex as far as material and design, and to be honest, there are not that many 2-stroke ring manufacturers. In the 2-stroke world, I only now of one company that manufactures both pistons and rings for 2 stroke engines, could be more but not many. The vast majority of 2-stroke  piston manufacturers source the rings from a few other company's and then it's the balance between cost, cylinder plating nikasil composition, sealing, and coatings/plating applied to the rings. There are basically 3 types of base ring material, cast iron, ductile cast iron, and steel, then a huge number of available treatments and coatings to those. Just so people know, when you said chrome moly rings, you were referring to a ring with a moly (molybdenum) coating applied which has fast sealing break-in but may not be as durable as some other coatings.

Greg         

Vintagesleds.com

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    alongtimeriding

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    Re: Kohler 250 liquid piston question
    « Reply #16 on: March 10, 2017, 12:16:54 AM »
    the rings I refere to are l-rings with the center machined out and molly inserted into the ring , its not a coating it is a inserted molly . most high performance ski-doo`s use it and the mercury twisters used it (elko`s ) , and probily others that used Elko or Mahle pistons

    gspaulding

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    Re: Kohler 250 liquid piston question
    « Reply #17 on: March 10, 2017, 12:34:11 AM »
    Hello alongtimeriding
    Yes I know the ring your talking about, cast iron with a molybdenum filler like an early Rotax 340-440 type. Seals quickly but not very durable and very sensitive to shock from pre-detonation in which case the moly flakes out.  Could be done again but expensive tooling and would need to be large quantity's to produce. The 250 Rotax (61 stroke) and I suspect the 250 Kohler liquid, did not have a moly filled L-ring, cast iron phosphate originally.
    Greg 

    popatopracing86

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    Re: Kohler 250 liquid piston question
    « Reply #18 on: March 13, 2017, 12:28:29 AM »
    All the Kohler twister motors came with a moly filled rigs and they work very well with all the new cylinder coatings out there the Kohler steel rings won't last long with the new coatings.  Now in my opinion from a performance stand point if I was to make pistons it would be with 2 1mm thin chrome face rings.   

    gspaulding

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    Re: Kohler 250 liquid piston question
    « Reply #19 on: March 13, 2017, 11:56:23 AM »
    Thanks for the info, I don't have an OEM Kohler 250 ring to look at but the Kohler 250 pistons and rings I'll produce will have a 1/2 keystone L-ring of cast Iron with a phosphate coating, the same as an OEM Rotax 250 ring and the same as the Rotax 250 pistons I offer now.

    Thanks
    Greg

    gspaulding

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    Re: Kohler 250 liquid piston question
    « Reply #20 on: March 21, 2017, 12:05:05 PM »
    Hello
    Anybody have a NEW Elko/Kohler 250 piston they would borrow me for a short time? I need to verify a couple dimensions before making them and just want to make sure of some dimensions since I've only had used ones to have measured. I could return it within a few weeks at the latest.

    Thanks
    Greg 

    sledwrenchin

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    Re: Kohler 250 liquid piston question
    « Reply #21 on: March 24, 2017, 01:25:19 PM »
    Sent you a PM

    back in the day racing

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    Re: Kohler 250 liquid piston question
    « Reply #22 on: May 19, 2017, 10:57:56 PM »
    Greg just looking for a up date. And did you find out if the rings will work on the stock Merc pistons. Thanks
    SRX RACER
    There comes a time when the ice and snow will melt.

    gspaulding

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    Re: Kohler 250 liquid piston question
    « Reply #23 on: May 22, 2017, 01:28:54 PM »
    Hello Back in the day.
    Sorry for the late reply. The Kohler 250 pistons are in process now and scheduled for mid to late Aug. As far as the L-rings, they are produced and I have them but they will not retro to the OEM piston. The OEM L-ring was a full keystone design and mine are 1/2 keystone like my Rotax 250 pistons. Also I had the 250 Rotax die modified to produce the 51.5mm Kohler pistons and I can't go back to a die that produced the 250 Rotax pistons. But on the good side, the die modification was much less than producing a new die for the Kohler 250 so I'll be able to reduce the price on the piston kits for both the Rotax 250 and the Kohler 250. Not sure how much quite yet but should be able to figure that out in a month or so.

    Thanks
    Greg 

    AllenJ

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    Re: Kohler 250 liquid piston question
    « Reply #24 on: May 22, 2017, 08:52:44 PM »
    Greg how many Rotax pistons did you have run before you changed the die?
    Deserve's got nothing to do with it.

    gspaulding

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    Re: Kohler 250 liquid piston question
    « Reply #25 on: Today at 12:40:00 PM »
    Hello Allen J
    I had 230 Rotax 250 piston kits produced.

    Greg