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Thread: ESE's works engine tuner

  1. #35176
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    8th February 2007 - 20:42
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    Thanks Frits , I have used your Torlon plugs in the KZ engine , and freaked out when the pins turned blue. Its hard enough to keep these engines together
    without the worry of a small end lubrication failure.
    Seems very strange that Jan says the Aprilia turned blue immediately , maybe with the Pankle stepped version , eventually the lube makes it thru into the piston load surface
    and the pin doesnt suffer anymore.
    As it stands , the laser welded caps I have made are working perfectly , not as cost effective as Torlons , but hell of a lot better than Pankle.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  2. #35177
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    18th May 2007 - 20:23
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    .
    Even more two stroke stuffing.......
    .

  3. #35178
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    18th March 2012 - 08:35
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    Homebuilt chassi, Kawasaki 212cc
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    Is it possible to use some other exclusive material in the whole pin?
    Like titanium or something, and run it solid.
    Maybe some ceramic?

    And is there an powerloss if having a boosthole in piston?
    This to ventilate the gasses under the piston.

  4. #35179
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    22nd November 2013 - 16:32
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    For piston pins to start going blue raises lots of questions. Look at a tempering colours for steel and, for blue, the temp is in the range of 250C plus. If the bluing is only in the ends and the central section and pin bearing are not discoloured, then the only logical conclusion is that the heat must be coming down thru the piston bosses. As Wob has pointed out, this occurs even with plugs which would prevent any hot gases being the culprit.

    If it is the piston transferring the heat to the pin, then one can conclude that the piston would have to be above this temp. With a cast hypereutectic piston, the T6 heat treatment requires an aging temp of around 210C. Anything above this would create softening of the material, both permanent and also being considerably weakened during operation at the higher elevated temps, maybe to half its original aged strength.

    Given this, one would think the pin boss bores would be flogged out, but this is not always the case. Perhaps there is so much distortion taking place there is no rotation of the pin, perhaps adding to thermal transfer to the pin.

    Could the bluing be some form of stain ? Intriguing.
    "Success is the ability to go from one failure to another with no loss of enthusiasm.

  5. #35180
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    16th April 2018 - 08:17
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    Quote Originally Posted by wobbly View Post
    So here is a pipe optimised for a piston port cylinder drag racing with a CVT.
    Most all piston port cylinders have crap transfer ducts that cannot be " fixed " except for introducing stagger and remedial work on the radial angles to help
    chronic short circuiting that occurs with anything even approaching a modern diffuser design.

    These old engines like a long header , much longer than we would even think of using today , as this helps to delay the depression formed around BDC , allowing the transfer streams to at
    least make a start up the Leaning Tower before being overcome , and creating a big loss in Trapping Efficiency.
    The mid section is as fat as I dare go , and its very long due to the steep rear cone.
    This is just for sharing and comparison.... here's an OEM pipe from a piston port (+tiny case reed) 530 parallel twin suzuki used in a snowmobile (CVT). This would nominally run about 8250rpm. DISCLAIMER: It's a stamped pipe so hard to differentiate inflection points. It could probably use better measurement resolution towards the end of the diffuser to capture more accurately.

    Click image for larger version. 

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  6. #35181
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    16th April 2018 - 08:17
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    Here's another oldy OEM pipe for a similar suzuki piston port (+ tiny case reed), this time 500cc. This is a 2 into 1 pipe, y-pipe not shown.

    Click image for larger version. 

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  7. #35182
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    20th April 2011 - 08:45
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    Quote Originally Posted by SwePatrick View Post
    Is it possible to use some other exclusive material in the whole pin? Like titanium or something, and run it solid. Maybe some ceramic?
    And is there an powerloss if having a boosthole in piston? This to ventilate the gasses under the piston.
    Titanium is too elastic to serve as a needle bearing surface, and coating it with a hard layer such as TiN or DLC won't help because this layer would be much too thin; the needles would 'sink through the ice', so to speak. A solid ceramic pin might fill the bill. It can be hard, light and probably also tough enough.
    However, a solid pin would help against gas flow through the pin, but that is not the problem. The problem is short-circuiting from the A-transfers to the exhaust and that can only be counteracted by 'closing' the piston skirt at the pin bores.

    I cannot see a reason for power loss through a boost hole in the piston. On the contrary, I remember a strange experience with a Rotax-124 kart engine.
    Its C-transfer port is fed in the now usual way via a duct from the crankcase; the cylinder has no provision for feeding the C-transfer through the piston.
    One race weekend we needed a new piston but the only available piston had a C-boost window. I could see no harm, so we fitted that piston, and all went well. Very well, so after the weekend I put the engine on the dyno and it produced more power than it had done with a closed piston.
    To this day I cannot explain what had happened. There could not be any gas flow through that piston window because the only time it opened, was when it ran over the C-transfer in the cylinder, and the pressures inside the piston and in the C-duct ought to be equal....

  8. #35183
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    8th February 2007 - 20:42
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    Back when the Rotax 256 was first introduced to Superkarts I was factory manager at Zipkarts in England.
    We were so excited I managed to get the boss Martin Hines to spend up large on a real Heenan Froude.
    This was pretty basic - it had no data logging , the only way to record the power/rpm was to use a VHS video camera and play the digital readouts back in slomo , and
    write down the numbers.

    Anyway I spent all the time i could on the new engine , even staying back at night dyno thrashing endlessly.
    With alot of hard pipe/port work I finally managed to get it over 13,000 where it promptly broke a rod and cut the front of the case completely in 1/2.
    As it was so new , Rotax actually coughed up a complete replacement - with new much heavyer rods.

    One of the best power advances was a 1/2 moon cutout in the boost port skirt , then I moved it up and it became a round hole about 16mm Dia with a corresponding hole near the bottom
    of the boost port duct.
    Later the factory , who refused to believe the power numbers we were getting ( until our world champ winning engine /pipes were sent to them ) changed the cylinder casting to our deep 1/2 moon cutaway at the boost port duct entry , just like the Aprilia got much later.
    That setup with a 1/2 moon in the skirt was factory stock for many years after - finally the skirt cutout was deleted as the restriction to the boost port entry no longer existed.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  9. #35184
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    2nd March 2013 - 15:04
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    Quote Originally Posted by Frits Overmars View Post
    One race weekend we needed a new piston but the only available piston had a C-boost window. I could see no harm, so we fitted that piston, and all went well. Very well, so after the weekend I put the engine on the dyno and it produced more power than it had done with a closed piston.
    To this day I cannot explain what had happened. There could not be any gas flow through that piston window because the only time it opened, was when it ran over the C-transfer in the cylinder, and the pressures inside the piston and in the C-duct ought to be equal....
    Is it possible that pressure in the boost port lagged a millisecond behind the pressure under the piston due to it's more torturous route, so that there was brief flow from under the piston into the port, thereby giving a tiny window of lubrication to the bearing?

  10. #35185
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    8th December 2014 - 14:39
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    1980 Suzuki Gs1100E
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    optimized piston port pipe w/ cvt

    Wobbly
    In your drawing of an optimized pipe for a singe exhaust port engine with cvt, would you explain why you added a 24.2 dia 20mm long section instead of just covering up the 24.2 dia end of the rear cone with the 28.6 dia silencer? By the way, thanks for the drawing. jfn2

  11. #35186
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    8th February 2007 - 20:42
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    The 24.2 dia is a 20mm long insert inside the front of a 28.6 dia ID standard size stinger tube.
    The insert effectively does all the restriction , and in effect negates most of the length and diameter effects of the stinger tube.
    I have found that having a stinger length about the same as the rear cone length minimises the effects as well.
    Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.

  12. #35187
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    14th April 2011 - 23:44
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    2008 Yamaha fino
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    Quote Originally Posted by Frits Overmars View Post
    Titanium is too elastic to serve as a needle bearing surface, and coating it with a hard layer such as TiN or DLC won't help because this layer would be much too thin; the needles would 'sink through the ice', so to speak. A solid ceramic pin might fill the bill. It can be hard, light and probably also tough enough.
    However, a solid pin would help against gas flow through the pin, but that is not the problem. The problem is short-circuiting from the A-transfers to the exhaust and that can only be counteracted by 'closing' the piston skirt at the pin bores.

    I cannot see a reason for power loss through a boost hole in the piston. On the contrary, I remember a strange experience with a Rotax-124 kart engine.
    Its C-transfer port is fed in the now usual way via a duct from the crankcase; the cylinder has no provision for feeding the C-transfer through the piston.
    One race weekend we needed a new piston but the only available piston had a C-boost window. I could see no harm, so we fitted that piston, and all went well. Very well, so after the weekend I put the engine on the dyno and it produced more power than it had done with a closed piston.
    To this day I cannot explain what had happened. There could not be any gas flow through that piston window because the only time it opened, was when it ran over the C-transfer in the cylinder, and the pressures inside the piston and in the C-duct ought to be equal....
    A solid ceramic pin was tried at Aprilia in 1995.
    I think it was made by Mercedes, but I am not sure.
    It broke at 10.000 in its first test....

  13. #35188
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    7th October 2015 - 07:49
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    honda ns 400
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    Quote Originally Posted by ken seeber View Post
    For piston pins to start going blue raises lots of questions. Look at a tempering colours for steel and, for blue, the temp is in the range of 250C plus. If the bluing is only in the ends and the central section and pin bearing are not discoloured, then the only logical conclusion is that the heat must be coming down thru the piston bosses. As Wob has pointed out, this occurs even with plugs which would prevent any hot gases being the culprit.

    If it is the piston transferring the heat to the pin, then one can conclude that the piston would have to be above this temp. With a cast hypereutectic piston, the T6 heat treatment requires an aging temp of around 210C. Anything above this would create softening of the material, both permanent and also being considerably weakened during operation at the higher elevated temps, maybe to half its original aged strength.

    Given this, one would think the pin boss bores would be flogged out, but this is not always the case. Perhaps there is so much distortion taking place there is no rotation of the pin, perhaps adding to thermal transfer to the pin.

    Could the bluing be some form of stain ? Intriguing.
    Maybe it could be the reason why some pistons are not lightening at place between crown and pin boss bores, just left all material without any inside or outside lightening. (add photos of cast Prox KTM sx 125 and forged YZR 500 pistons)
    Honda stick to outside cavity type shape for Rs 125/250, but pin boss bores are coated with some material. Is it thermal barrier or sliding coating or both?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  14. #35189
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    18th April 2017 - 23:08
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    Quote Originally Posted by ken seeber View Post
    For piston pins to start going blue raises lots of questions. Look at a tempering colours for steel and, for blue, the temp is in the range of 250C plus. If the bluing is only in the ends and the central section and pin bearing are not discoloured, then the only logical conclusion is that the heat must be coming down thru the piston bosses. As Wob has pointed out, this occurs even with plugs which would prevent any hot gases being the culprit.

    If it is the piston transferring the heat to the pin, then one can conclude that the piston would have to be above this temp. With a cast hypereutectic piston, the T6 heat treatment requires an aging temp of around 210C. Anything above this would create softening of the material, both permanent and also being considerably weakened during operation at the higher elevated temps, maybe to half its original aged strength.

    Given this, one would think the pin boss bores would be flogged out, but this is not always the case. Perhaps there is so much distortion taking place there is no rotation of the pin, perhaps adding to thermal transfer to the pin.

    Could the bluing be some form of stain ? Intriguing.
    All the used pankl pins I have seen look like below. Maybe makes sense as the area for heat radiation decreases when closing the sides
    However, this has not always been the scenario when they (the plugs) were made of a material with less thermal conductivity and mass.

    Fritz is right as usual!
    I think there is something linguistically wrong on my part that makes me want to put in that E.
    Sorry for my substandard spelling, I'll try to get better
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by Muhr; 8th March 2021 at 01:50. Reason: A bad habit of misspelling
    No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

  15. #35190
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    20th April 2011 - 08:45
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    Guys, in case you are having problems finding things with Google: there's no e in Pankl
    https://pankl.com/en/

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