There are a few problems to sort out with the engine. Firstly the electric pump is not working as well as I would expect. More immediately important are a couple of steam leaks. There is a leak at the joint through the right hand wing plate where the main steam pipe joins the lubricator. The other leak is where the main steam pipe joins the cylinder block. Both are sealed by 'O' rings which tend to blow out under high pressure. They should be ok once I have found a way to constrain them somewhat.
The new motor is much bigger
The new motor has much chunkier gears. It has a 6mm shaft rather than 4mm so the crank disc needs to be modified. I made a new disc so that I could put the old motor back should the need arise. The motor shaft has to be shortened. New mounting holes are needed through the frame and the pump conn rod now needs an offset in the opposite direction. To ease fitting the battery the bracket under the control box was narrowed. The job took quite a long time as various bits and pieces have to come off before you can get at the motor and electric pump. Once the pump is in place they all have to go back.
New larger motor in place
In the process of undoing the pipe from pump to boiler I managed to twist the boiler end of the pipe severely. Making a new end involved silver soldering a new pipe nipple and a short jointing piece of pipe.
Having tested the new pump against an air compressor I was reasonably confident that the electric pump could now overcome working pressure to get water into the boiler. In the process I blew the fuse in the control box. I do hope this is not a sign that the new motor draws too high a current.
With the pump in place I turned my attention to the problems with 'O' ring seals mentioned yesterday. I turned up a narrow ring to surround the 'O' ring seal between the main steam pipe and cylinder block. I also turned short tubes to fit over the main steam pipe to lubricator joint. These now await another steam test.
Modified steam pipe to lubricator joint
Trying out seating position on the riding truck
Here is a video clip from today
I modified the safety valve by adding an 8BA grub screw to lock the setting as recommended by the boiler inspector. He had also advised looking at the saftety valve spring. He advised that the ends of the spring should be flat to stop the valve stem canting over. I followed his advice and tweaked the ends of the spring so that it would stand upright on a flat surface. After reassembly the valve seemed to work more cleanly on air, that is opening sharply at the right pressure and closing again with only a small pressure drop.
Here are a couple of photos taken today.
The builder awaiting the green flag to start off up the lawn. The riding truck is on loan - Thanks Edward!
Passengers seem to enjoy the ride even if the truck is a little cramped.
Two issues have been resolved, the sticking reverser mentioned before and the smokebox seal. The reversing problem turned out to be caused by interference between the clevis on the valve rod and the left hand expansion link. To solve this without dismantling the loco I ground down a rifler file so it would just fit under the clevis with the exoansion link in mid gear. Though it took a few hours to find the cause it was the work of moments to resolve. The reverser now operates smoothly with the expansion link in all positions.
I found out that the smokebox was not air tight by accident. I inadvertantly disconnected the fan from the battery whilst raising steam. Smoke emerged from below the smokebox lid on all sides. A ring of silicon sealing compound has cured this. Steam raising is now quicker and the fire burns brighter and hotter. So hot in fact that the paint on the chimney has started to flake off.
Here are two video clips of Chaloner on the Stafford & District Model Engineers track.
