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Thread: Oddball engines and prototypes

  1. #2806
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    Quote Originally Posted by ken seeber View Post

    Will,
    Ozzies don’t bulldust, just bullshit.
    Bulldust (to those who may not understand) is just airborne bullshit!
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  2. #2807
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    Ken, maybe since it was a near-horizontal cylinder Laverda thought they needed extra help since the oil wouldn't just fall into the sump? But then the late 1960s Guzzi V7 also had an extra scraper ring

    From a Mick Walker book: "The following year, 1968, saw the 700cc V7 continue, but now with a new starter motor and the carburettors changed to square slide ... A new type of piston was used although there were still four rings, the oil scraper was moved to join the other three above the gudgeon pin and the skirt was relieved to give an almost semi-slipper type appearance."

    Here's a link to a photo of one of the Guzzi pistons:

    Click image for larger version. 

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    cheers,
    Michael

  3. #2808
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    Rings at the skirt bottom is quite common in aircraft engines,the Continental O-200 has the oil control ring at the bottom of the skirt;
    http://www.aircraftspecialties.aero/piston-aec530348/
    The bigger Continental 470,520,&550 engines have the oil control ring above the piston pin,but have an oil scraper ring in the skirt which
    scrape 'up' to keep an oil film between it and the control ring;
    http://www.aircraftspecialties.aero/...nced-654850bp/
    ..All these designs are direct drive,low RPM(2850 max) engines of old design,but very reliable..

  4. #2809
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    Quote Originally Posted by 190mech View Post
    Rings at the skirt bottom is quite common in aircraft engines,the Continental O-200 has the oil control ring at the bottom of the skirt;................................All these designs are direct drive,low RPM(2850 max) engines of old design,but very reliable..
    Do those aircraft engines need the extra rings for inverted flight?
    I once (illegally) checked out a Hiller crop spraying helicopter parked in a field on our neighbour's farm for the night and being a teenager with a couple of friends, started it up too! - (I also had some lunatic thoughts of taking off as well- but commonsense prevailed!)
    I did however notice that it had a flat 6 Lycoming engine mounted with its crankshaft sitting vertically - I guess this would be a case where an extra oil scraper would be necessary?
    I'm also supposing they had seperate oil tanks with scavenge pumps in the crankcase?
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  5. #2810
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    Quote Originally Posted by WilDun View Post
    Bulldust (to those who may not understand) is just airborne bullshit!
    Damn Fine Bullshit!

    Cheers, Daryl.

  6. #2811
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    Quote Originally Posted by Pursang View Post
    Damn Fine Bullshit!

    Cheers, Daryl.
    Seriously though, it was brought home to us in Auckland (NZ) last Sunday - when we looked out at 3 pm it was like looking at twilight through yellow tinted sunglasses! - sure brought it home to us just what it might be like in Australia ........ to you overseas guys, (just to get it in perspective), - Australia is at least a 3 hour plane trip across the Tasman sea! . ......... no bullshit!
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  7. #2812
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    Daryl, I reckon I've seen something like this handy bike stand before - can't remember where!
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  8. #2813
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    Quote Originally Posted by WilDun View Post
    Daryl, I reckon I've seen something like this before - can't remember where!
    Strong Meds will do that!....but you don't want to spend too much time hanging around here!

    Click image for larger version. 

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    These have electric lift & tilt. Rated for hundreds of kg's.

    Bargain priced, when they 'date out' and need to be disposed of.

    Don't google 'motorcycle lift / workbench' etc.


    Cheers, Daryl.

  9. #2814
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    Talking about prototypes, what do you think F1 and Moto GP are brewing up on a two stroke platform?

    Back in the sixties when all those wonderful new ideas kept pouring out from the manufacturers - the lead up to the 1962 (first) 50cc IOM TT was on and very exciting, - every man and his dog wanted to enter his 'specially tuned fast 50' - some even claiming 70 mph! - it was completely unknown what the manufacturers were going to come out with!

    In the actual event it turned out that all the home brewed fifties were not quite up to competing with the works machinery and Honda and Suzuki probably did a better average speed than the the others top speed! - i think they were reaching top speeds of around 115 mph! - i seem to remember the Kreidler was the best of the road bike based entries (I think it had a compound gearbox (4X3, giving it 12 speeds) but I'm sure Frits knows more..

    So I'm hoping we get the same sort of surprises when (if) these new two strokes eventually do become reality!
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  10. #2815
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    Quote Originally Posted by WilDun View Post
    ... i seem to remember the Kreidler was the best of the road bike based entries (I think it had a compound gearbox (4X3, giving it 12 speeds) but I'm sure Frits knows more..
    Those 12-speed Kreidlers had little in common with their road-going cousins: rotary inlet discs on both sides of the engine and indeed twelve speeds. Initially 4-foot x 3-hand like you say, but downshifting without losing count was a nightmare for the riders, so the later versions had 6-foot x 2-hand. I posted pictures of both versions here some time ago: look for Kreidler 12V. Or you can take a look at the FOS Google drive: https://drive.google.com/drive/folde...rNTk89_KgwgWof

  11. #2816
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    Quote Originally Posted by Frits Overmars View Post
    Those 12-speed Kreidlers had little in common with their road-going cousins: rotary inlet discs on both sides of the engine and indeed twelve speeds. Initially 4-foot x 3-hand like you say, but downshifting without losing count was a nightmare for the riders, so the later versions had 6-foot x 2-hand. I posted pictures of both versions here some time ago: look for Kreidler 12V. Or you can take a look a the FOS Google drive: https://drive.google.com/drive/folde...rNTk89_KgwgWof
    Thanks Frits for sharing your treasure trove!! ....... (you're right up there with Husa!!)

    I have only just started to go through all the stuff I thought I would never see again - I guess we were lucky in that we grew up through the post war explosion of new ideas, some ridiculous, some very successful - but all very exciting stuff!
    Kreidler at that time (until Jamathi came along) certainly kept Europe afloat through the Japanese explosion! but unfortunately, it was getting to the stage where only the rich manufacturers were able to continue with their (ridiculous) innovation and the ordinary guys couldn't compete (again except Jamathi).

    Also road bikes weren't ever likely to be able to follow suit in their designs and much as I hate rules, this is one case where rules did work extremely well, that is when fifties and 125 classes became restricted to single cylinder and six speed - instead of 14 speeds and 3 cylinder fifties (as Suzuki were trying when it all changed)! that's when they actually started (forced ) to look for more torque and less revs! instead of the crazy stuff of the late sixties!

    The (short lived) Bridgestone fifties (yes, the Bridgestone tyre company) were right in the thick of it as well! - ie until forced to concentrate on tyres by the other Japanese companies - or so I'm told! ..... Tohatsu were in the mix as well!

    Oh no! - I'm off again! - and just as I thought I was winding down!

    As I said, i've only just started to look through all your stuff - thanks again.
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  12. #2817
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    Still here, just waiting at the dentist.
    I guess I might have some stuff to put up soon.

  13. #2818
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    Quote Originally Posted by Flettner View Post
    Still here, just waiting at the dentist.
    I guess I might have some stuff to put up soon.
    That sounds good!
    We have had some stuff from Frits pop up - lots of stuff I hadn't seen for years (much worth revising).
    I thought Husa had just about everything in his (missing??- confiscated?) archives. - still we can maybe look to the future now, seeing that F1 and Moto GP are actually contemplating using two strokes would you believe!

    However, the whole automotive market may then start looking in the direction of using new clean two strokes, ie if they can break into the mindsets of the people who matter ....... customers! - and that will take some proper marketing expertise I guess!

    Ironically, I (grudgingly) have to admit that I actually admire Harley Davidson for doing just that, by still managing to sell early post war designs ..............70 years later!!
    Freedom of speech is important - but
    P.C. has destroyed our right to speak the truth.

  14. #2819
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    I thought this might be the place to post seeing as it’s and oddball idea.

    So hearing about how someone somewhere has been discussing the possibility of using a two stroke engine in F1 at some stage in the future, I remembered Ferrari had made a two stroke prototype engine at one stage. I noticed this engine had an OHV for the exhaust.
    So I thought to myself what would be the flaws in having an OHV two stroke but placing 4 small inlet valves in the head and running the exhaust ports down the bottom like in a normal two stroke with conventional expansion chambers. The inlet valves would open with standard durations when the transfer ports would normally open.

    I can see the pros being:
    -more exhaust area
    -wet sump for higher rpm
    -better for emissions with no oil in the fuel
    -less wear
    -getting the benefit of the expansion chambers
    -cooling the bottom of the piston with oil sprayers

    Cons being:
    -more parts and cost
    -most likely everything escaping straight out of the exhaust

    So I would appreciate if someone could poke some more holes in this idea for me.

  15. #2820
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    Rpm would be restricted due to poppet valve limitations. A conventional disk valve engine would work well in a hybrid drive with an exhaust turbocharger. An electric drive turbo could allow a wet crankcase, but you would loose the natural piston cooling of a crankcase scavenged engine. That's not too different from current systems. Even more power could come from an opposed piston, FOS, or sleeve valve engine. Piston cooling could come from crankcase oil spray into the piston.

    Lohring Miller

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