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Thread: Oddball engines and prototypes

  1. #1606
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    a thinner version of you grumph!!!!!!!!!!!!
    riding history into the future since ages ago.

  2. #1607
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    Quote Originally Posted by robajs View Post
    a thinner version of you grumph!!!!!!!!!!!!
    I am jealous of that beard....
    Reason is a tool - remember where you left it..... The late, great, John Clarke

  3. #1608
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    Quote Originally Posted by Pursang View Post
    No wonder I like the whine of quick change gears,
    my Dad built and raced Midgets in the 50's
    Cheers, Daryl

    So is that Vic Tracey any relation to Ted Tracey, who used to be pretty big in Auckland speedway? (Ted Tracey Motors)
    it's not a bad thing till you throw a KLR into the mix.
    those cheap ass bitches can do anything with ductape.
    (PostalDave on ADVrider)

  4. #1609
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    11th October 2016 - 21:23
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    Quote Originally Posted by Frits Overmars View Post
    In case you want to extract the angle.area values from those older engines: don't; it will blurr your view.
    Here is something a little less vintage, that I posted on the French Pit-Lane forum: http://www.pit-lane.biz/t6246p25-gp1...vermars-part-5
    Attachment 331772

    PS: did Agnetha, Björn, Benny and Anni-Frid really make it to the Nobel Committee? I think I like their music after all .
    Perfect!

    I had seen the graph and have those area numbers as reference in my spredsheet, but hadn't seen the text with the real meat. Thank You!

  5. #1610
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    18th July 2015 - 16:21
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    Quote Originally Posted by Frits Overmars View Post
    In case you want to extract the angle.area values from those older engines: don't; it will blurr your view.
    Here is something a little less vintage, that I posted on the French Pit-Lane forum: http://www.pit-lane.biz/t6246p25-gp1...vermars-part-5
    Attachment 331772

    PS: did Agnetha, Björn, Benny and Anni-Frid really make it to the Nobel Committee? I think I like their music after all .
    Frits,if this idea is applied to the MB40 engine, what numbers do you get. I now have an MB40 engine, and can measure the transfer are and timing and the exhaust, so will be able to follow the example better. Your above example I am not able to follow sorry.
    Neil

  6. #1611
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    Quote Originally Posted by Frits Overmars View Post
    In case you want to extract the angle.area values from those older engines: don't; it will blurr your view.
    Here is something a little less vintage, that I posted on the French Pit-Lane forum: http://www.pit-lane.biz/t6246p25-gp1...vermars-part-5
    Attachment 331772

    PS: did Agnetha, Björn, Benny and Anni-Frid really make it to the Nobel Committee? I think I like their music after all .
    Plugged the numbers in and was puzzled about getting about 2x the Aprilia values from my cylinder. Then noticed that the picture says effective areas... Am I correct to assume I should use the classic mean (angle) area for the calculations?

  7. #1612
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    28th November 2013 - 21:58
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    Quote Originally Posted by Grumph View Post

    Here's a pic for Daryl - just to whet your ambition....
    Bit further on.
    Attached Images Attached Images
    Note to self: Before posting anything, search ESE thread, it's probably already in there!

  8. #1613
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    Quote Originally Posted by Jannem View Post
    Plugged the numbers in and was puzzled about getting about 2x the Aprilia values from my cylinder. Then noticed that the picture says effective areas... Am I correct to assume I should use the classic mean (angle) area for the calculations?
    Plugged the numbers in where?
    You may also want to take another look here, regarding your mean area: https://www.kiwibiker.co.nz/forums/s...post1131055378

    Come to think of it, maybe a more fundamental explanation may be in order:

    Blowdown angle.area

    Blowdown angle.area is not simply the total blowdown area multiplied by the total blowdown angle. It is the sum of a lot of small area steps, multiplied by the time during which each of these steps is open.

    For example, let us assume that the exhaust port is a simple rectangle, 40 mm wide, that it opens 1 mm further for each degree of crankshaft rotation, and that the total blowdown angle from the point where the exhaust port is beginning to open till the point were the transfer ports are beginning to open, is 30°.
    Then the first degree of exhaust opening will open an area of 40 mm x 1 mm = 40 mm², and this area will be open during the whole 30° of blowdown period. That first area thus has an angle.area of 30° x 40 mm² = 1200°mm².

    When the crankshaft turns 1 degree further, an additional area of 40 mm² is opened. This second area will be open during 29°, so its angle.area is 29° x 40 mm² = 1160°mm².

    Repeat this calculation for each crank degree until the end of the blowdown phase, and add all the angle.area values; that will give you the total blowdown angle.area.

    In reality this calculation is complicated by the fact that not every degree of crank angle gives the same port height difference, and even more complicated by the fact that the exhaust port is not a simple rectangle. But you will understand the principle of angle.area.
    ================================================== ==============================

    Transfer angle.area

    Let us assume a transfer port with a timing of 130°.
    When you turn the crank 1º past Transfer Open, a certain area of port, say A1, will be exposed. I don't know or care what that area is, that's for you to measure.
    That area of port A1 will be open for 130º. The angle.area for this area A1 is = 130 x A1.
    Turn the crank another 1º and an additional area of port, A2, will be opened.
    This additional area A2 will be open for 128º. The angle.area for this area is = 128 x A2.
    The next degree of crank rotation will open Area A3 which will be open for 126º and its angle.area will be 126 x A3.
    Keep going like this until BDC, then add up all the angle.areas you have calculated.
    The total is the angle.area for that transfer port.

  9. #1614
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    Quote Originally Posted by pete376403 View Post
    So is that Vic Tracey any relation to Ted Tracey, who used to be pretty big in Auckland speedway? (Ted Tracey Motors)
    The Tracey was Fred Tracey, former Solo rider and then promotor.
    (Vic) was for Victorian Drivers.

    fredtracey1938.jpg

    Cheers, Daryl

  10. #1615
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    Quote Originally Posted by Lightbulb View Post
    Frits,if this idea is applied to the MB40 engine, what numbers do you get. I now have an MB40 engine, and can measure the transfer are and timing and the exhaust, so will be able to follow the example better. Your above example I am not able to follow sorry.
    Here you go Neil.
    MBFGAL30.png
    If your MB40 engine is recent, you will have a narrower exhaust port and an accordingly smaller blowdown angle.area than the value shown in my picture.
    These small methanol-burning engines have lousy carburation because the fuel is not sucked in by the air flow passing through the carb, but pushed in by means of exhaust pipe pressure exerted on the fuel bladder. Big globs of fuel enter the engine with no time at all to evaporate, so the mixture will be anything but homogeneous;
    it will vary from very rich to very lean all over the place.
    In order to get anything like a decent burn speed the mixture needs pre-heating by means of mixing with spent gases, so a blowdown time.area that would be too small for a bigger engine, may work better in these small screamers. It took me quite some time to grasp this...

  11. #1616
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    Quote Originally Posted by Grumph View Post
    Those pics take me back. Very similar atmosphere at the time on this side of the Tasman. Push starting race cars on grass....

    The Standard Vanguard engine was not used as much as it could have been for motorsport. Triumphs obviously, but special builders didn't seem to want to use it - and it was common as they were assembled here. My old man worked at the assembly plant in ChCh as a day job.
    Hec Green's ChCh built twin cam alloy race engines were built around the Vanguard crank - supplied courtesy of the old man...
    Quote Originally Posted by WilDun View Post
    That engine was very good and was used in just about everything from Fergie tractors to family cats to Triumph sports cars (diesel versions too - as used in the Fergie Diesel tractors and some Taxi cars in Britain - these were very successful and the sweetest running little diesels ever, however not so well known in NZ, just in the tractors at the airports, also used in Antarctica by Edmond Hillary).
    I would be interested in the twin cam alloy engine too, did he use any other Vanguard parts other than the crank? (eg the wet liners).
    Dad fitted the Vanguard in the early 50's, replacing a 4cyl Chrysler. He worked at a big Standard dealership. The engine block was rescued from the rubbish bin, it had thrown a rod out the side and had been replaced under warranty. The block was patched, the rest was usable. It was pretty high tech at the time, most midgets still ran Model A, V-8 60, Jeep, Studebaker's & JAP V-twins. They quickly discovered it's deficiencies for racing. First problem was the valve spring retainers, these were a stepped ring with a slotted hole to fit into the groove in the valve. Uniquely, the longer outer 'retaining' spring was quite soft and the inner was the strong one. Clever idea for easy assembly & quiet operation, but highly likely to spit out the retainers and drop valves when revved. Early crankshafts were soft and needed nitriding to prevent journals going out of round. The cylinder head has a large water passage over the gap in the liners between 2 & 3. The gasket is only supported by the top edge of the liners and is prone to blowing out there. Although not officially sponsoring the car (except the 'under the counter' parts, especially new big end bearings, every week) the Dealer did send reports to the UK and many things were rectified by the time the Triumph versions were released (except the head gasket issue). The Vanguard was eventually replaced with the ubiquitous grey (side-plate) Holden 6 cyl.

    I think I've discovered the cause of the big end bearing problem, which is good, I'm rebuilding this version of the car from original parts.

    cheers, Daryl

  12. #1617
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    Quote Originally Posted by Frits Overmars View Post

    Come to think of it, maybe a more fundamental explanation may be in order:

    Blowdown angle.area

    Blowdown angle.area is not simply the total blowdown area multiplied by the total blowdown angle. It is the sum of a lot of small area steps, multiplied by the time during which each of these steps is open.
    Ah ha! lightbulb1.jpg

  13. #1618
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    Quote Originally Posted by Grumph View Post

    Here's a pic for Daryl - just to whet your ambition....
    Quote Originally Posted by guyhockley View Post
    Bit further on.
    I really hope that just one cylinder will be enough to do the job.

    Cheers, Daryl.

  14. #1619
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    Thanks Frits, that explains a lot more. Yeah the fuel delivery is really bad, and efforts to make it better a atomisation for the effort did not deliver any more power. Part of that could be that when it does get a better atomisation, then requires a larger blow down more approaching that of the petrol engines. Something that we did not try and so may have missed the boat on that testing series.
    Neil

  15. #1620
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    When I first arrived in NZ in 1966, (51 years ago, - still can't believe it!!) - I had never seen either Motorcycle speedway or Midget Car racing and I remember that the Holdens were starting to gain control - that was way before the VW's (or derivatives of) had taken over and I was hearing the name "Offenhauser" a lot. I was told that their cylinder blocks and heads were 1 piece castings - what happened to the Offenhausers?
    I never did get to see one.
    Freedom of speech is important but if what we say is incorrect, our peers will quickly put us right.
    P.C. will eventually destroy our right to tell the truth.

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