Stuart Triple Question

[atomarcParticipant @atomarc]

I’ve machine the eccentrics for the valve timing as separate pieces versus the double castings supplied by Stuart-Turner. The print calls for offsets of 30 degrees on one set and I believe 15 degrees on the other two. I can join my separate pieces to these offsets, but I would love to know if they are indeed dead nuts accurate. Keith Appleton(?) also does his separately to achieve more precise FWD-REV operation of the engine.

Should I affix my two pieces together at the factory supplied offsets..OR, leave the separate so I can tweak the timing to perfection?

My first assumption would be that Stuart-Turner has their ducks in a row and that I should follow their prints and offset the eccentrics per the drawing.

Thanks,

Stuart Miller

Eureka, CA USA

[JasonBModerator @jasonb]

Use the Stuart settings as a starting point and then adjust if needed. Timing will depend to some extent on whether you are just running the engine unloaded for display or want it to work under load. Air running will again be different to steam as will the pressure of both affect things.

[atomarcParticipant @atomarc]

Jason,

 

Thank you for that note. I’ll only run the engine on compressed air..no steam. So, what you’re saying is, affix the two eccentric halves together at the Stuart offsets, then adjust as a unit together on the crank to fine tune timing…at least that’s how I interpret your post.

 

Thanks,

Stuart Miller

[JasonBModerator @jasonb]

No doing them as a unit on the crank will only allow for making sure you have the same timing for forward and reverse.

For tweaking performance you need to alter the angles so for example the HP rather than being 30/30 may need changing to 25/25 or 20/20 as you don’t need as much lead when running on air.

Also debatable if it will run as a triple on air, some people leave the valve or piston out of one of the three so the air just runs straight through or you may need to feed air to HP and IP

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