ValveGear getting close

Close but no coconut

I have been working on the valve gear completing the expansion links and die blocks. The link slots are longer than designed (due to iffy dimensioning on the drawings), so I made the die blocks longer to match, so I think all should be OK.

Colin Sims and I have been debating if the eccentric rods are too long, and having now assembled the LP Valve gear I can confirm they are!! I have ad to shorten the clevis (?) at the bottom of the valve rod, and also shorten the valve rod to get everything to fit – not a complete disaster, but it seemed to be about 3/8″ long over all…

Worried about LP Valve too

Having now assembled the LP gear I could not resist applying some compressed air to see what happened – and what happened? The valve leaked (a lot). Inspection revealed that the eccentrics and eccentric rods are too close to the valve chest, and so exert some side pressure on the valve rod, and the design of the “buckle” means that this resulted in the valve being held off it’s seat. I am sure this is all as a result of inaccuracies in my machining, but it’s still a bit of a concern.

A normal slide valve buckle allows the valve to settle smoothly onto the port face, but the circular arrangement in the Leak has the opportunity to hold it at an angle in either the vertical or horizontal plane. Disconnecting the expansion link from the valve rod, resulted in the valve seating, so I think it’s just a matter of providing enough “slop” to prevent the crank endfloat from forcing things out of line…

However, I also found if I upped the pressure the balanced valve started to leak. – It  seemed to be that the part a the valve bearing on the valve chest cover is forced off it’s seat.  (not a good sign). It would appear that there is insufficient surface area on this part of the valve to hold it in contact with the cover, a large change!.. Time will tell…

Some picks of machining the links and assembly…

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