Centaur gas engine valve springs

[Maurice Cox 1Participant @mauricecox1]

[Maurice Cox 1Participant @mauricecox1]

I am involved in helping a friend to complete a part built Centaur gas engine. The cylinder head, valves and rockers are parts that have already been finished to a high standard, but the valves take a thrust of about five pounds to lift them off their seats. Is this normal please? It seems a lot of work for the cams to do. I have built steam engines for over fifty years, but this is my first experience of I/C. Any advice would be welcome.

Thanks in advance Maurice

[Johan van ZantenParticipant @johanvanzanten]

Hi Maurice, I se nobody answers your question. I never build the Centaur engine but lost of other designs. I think 300 to 600 grams is more than enough. Don't use needless strong springs to prevent exessive wear on the cams. Succes with your engine. Regards, Johan.

[Maurice Cox 1Participant @mauricecox1]

Thank you for your help Johan. I thought that the existing springs were ridiculously strong. Your reply confirms this. One more thing to correct! Oh well…..

Thanks again Maurice

[Roderick JenkinsParticipant @roderickjenkins93242]

Hi,

I've just done a quick check on my Wyvern and get 1.9lbs to hold the inlet valve fully open. I don't suppose the Centaur needs any more – I doubt that valve bounce will be an issue!

HTH

Rod

[Maurice Cox 1Participant @mauricecox1]

Thanks Rod, I now have a target to aim for. Can't think why the ones fitted were chosen. But then, seeing just how badly some of the work on this engine has been done, it should be no surprise to me. Thanks again

Maurice

[Roderick JenkinsParticipant @roderickjenkins93242]

Maurice,

I wound my springs from 22SWG wire. I did a little photo essay here: **LINK**which showed me winding the Wyvern springs – Post on 4/7/2014

Rod

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