Springless valve train for BBC
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Springless valve train for BBC

  1. #1
    Satisfied Member Mid-Life Crisis's Avatar
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    Default Springless valve train for BBC

    Hey Guys, I rarely post on here and am not a technical guru by any stretch when it comes to BBC's.. I just want to know if any of you on the boards have had any experience with this springless valve train system? It looks like a really good idea but don't know if this would only work on a low HP N/A application or if you could use it in a high horsepower Blown racing application.

    The strong points of eliminating the spring pressures are easy to see, but what would be the weakness??

    Decuir Engine Technologies

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    Senior Member lilrick's Avatar
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    Keep your eye on the ball and quit worryin about all of this other chit! Now, how far along is that sled yuh fag?

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    Satisfied Member Mid-Life Crisis's Avatar
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    Quote Originally Posted by lilrick View Post
    Keep your eye on the ball and quit worryin about all of this other chit! Now, how far along is that sled yuh fag?
    All the stuff I need to do is done...just waiting for the phone call...Just bring your jalopy to puddingstone and take your beating like a man!!

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    Senior Member Uncle Dave's Avatar
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    Another take on the demosdromic system Ducati uses in their motorcycles.

    Downside is added reciprocating weight and valve adjustments are typically much more time consuming.

    Clever though implementation though.


    Uncle Dave

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    Default Springless?

    Seems there would have to be a spring somewhere in the system?.... Maybe not on the valve stem, but somewhere... I have no sound, so I couldn't hear the video, but something has to force the lifter back down as the cam goes over center...AND, zero lash???....
    Ray
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    Senior Member snoopjonnyjon's Avatar
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    Here's a thread from earlier in the year about the same topic.

    Why don't we see more of this ???

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    Senior Member Uncle Dave's Avatar
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    Quote Originally Posted by Moneypit View Post
    Seems there would have to be a spring somewhere in the system?.... Maybe not on the valve stem, but somewhere... I have no sound, so I couldn't hear the video, but something has to force the lifter back down as the cam goes over center...AND, zero lash???....
    Ray
    There is a follower on the opposite side of the cam lobe that closes the valve. Think of the lobe rotating in a square- when it hits the front corner it pushees the valve open - when it hits on the back corner it pulls.

    Yeah and adjusting that "zero lash" adjustment part- is like a science project.

    Basically its an answer to the spring problem with a few more reciprocating parts- it does work well though watch a a ducati twin run with a jap inline 4 - then watch the guy adjusting it the next day.....


    UD

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    gn7
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    Quote Originally Posted by Moneypit View Post
    Seems there would have to be a spring somewhere in the system?.... Maybe not on the valve stem, but somewhere... I have no sound, so I couldn't hear the video, but something has to force the lifter back down as the cam goes over center...AND, zero lash???....
    Ray
    Still using those pesky piston return springs aren't you Ray.

    LINK: piston return springs
    LINK:GN-RACING.COM

    "there are too many pigs for the teats"
    Abraham Lincoln

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    Satisfied Member Mid-Life Crisis's Avatar
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    Quote Originally Posted by snoopjonnyjon View Post
    Here's a thread from earlier in the year about the same topic.

    Why don't we see more of this ???
    OK then.... looks like this topic got beaten down like a rented mule by GN-7, so I guess I'll just stick to Jessel shaft rockers..

  11. #10
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    Default Nah....

    Quote Originally Posted by gn7 View Post
    Still using those pesky piston return springs aren't you Ray.

    LINK: piston return springs
    Nah, the shims kept falling out and I couldn't keep the piston return pressures within tolerance to each other. The boat would speed up and slow down whenever it felt like it......... I'm all about precision...
    Ray
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  12. #11
    Senior Member Uncle Dave's Avatar
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    The desmo type valvetrain is very cool and works, just dont know how practical it is because off what the real trade offs are.


    Another real cool idea, that doesnt seem to get much play....

    Coates International Ltd. - Home


    I wold imagine the big gremlin ion this setup is the sealing.


    Uncle Dave

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