ME 4761 – Sirius Piston Valve C**k up Corner

[Charles LamontParticipant @charleslamont71117]

I am surprised this 3-page article by Graeme Quayle has been published apparently without sanity checking the content.

This bloke has based the whole thing on an evident total misunderstanding of the Sirius’s valve design. His new valve ‘works’ on the wrong edges altogether.

I don’t have the drawings, so I can’t check the dimensions, but I think there can be little doubt that the original valve as drawn was fine. If there had really been a problem with it, it would have been known about long ago.

This needs a correction printing ASAP.

[JasonBModerator @jasonb]

I don’t have the Sirus drawings but if the Sun is anything to go by then  the bottom image in fig 3 has the valve in the wrong place, The widened 1/4″ section is not meant to be in the middle. This is the same way as the old Stuart drawing in Fig 1 has it.

Also Photo 4 shows the two full diameter parts of the new piston valve the same width but the drawing says the one at the end is 5/32 and the other 1/4″

Seems to have missed the point that it is inside admission and the inlet passage should nor be covered at any time

Looks like Cock up corner will be continuing into the new mag!

[Charles LamontParticipant @charleslamont71117]

Yes, its a sirius error.

[JasonBModerator @jasonb]

I am 99% sure that the Sirius is the same as the Sun and that the ports between cylinder and valve are machined. these are the important ones not the rough cored ones to the exhaust at the top and within reason the central hole to inlet is not an important size and could probably be anywhere from 3/16″ to 5/16″  and still work without problem using the valve as drawn on either of the Stuart drawings.

 

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