Now with the new parts installed the engine was run once more and this times things were much better it was a bit stiff but as a fellow engineer used to say “its only the newness”And after setting and resetting the valve timing and letting the engine run for 30 minutes it soon showed that the extra work paid off and it had lots of steam and power the speed at full boiler pressure was great enough to run the engine off the curves despite its slightly smaller wheels.
Here you see it as I have just managed to catch it as it nips round my small track with 2 coaches on
I did add a set of rubber tyres to the third set of drivers these were the standard Hornby tyres for the A3 and A4 and appear to fit ok.
I still have the problem with the rear truck wheels and as you can see from these pictures just how far the rear end of the chassis swings over the rails making things hard to work as the full size engine with flanged wheels.
Another problem I found was the pivoting Hornby connecting rods these seam too flexible and would lend them selves to locking up the wheels and in some cases jam the quartering or slow the engine down so a quick fix was to solder the flexible link on the rear of the rod on the second driver this was the wheel set connecting to the piston and was therefore delivering all the power to the wheels especially the set with the rubber tyres on.
The fixing points were made to fit the body to the chassis this way I could get an idea as to how thing were working out and all looks fine the steam exhaust from the working chassis was almost directly under the hole in the brass body so no real problem there the only thing to change was the very front of the oil tank which needed more of an angel to match the angel of the front of the brass body so a little filing and this fitted better.
Still thinking on the working valve system for the model i came up with this idea which is to take the drive from the Hornby valve system and extend it out the front of the valve cover and with a small double pulley and 2 rubber o rings drive 2 small shafts above the cylinders and then down to the second drivers this way as the engine moved along the small shafts would rotate and look like the full size engine but we will see as there is still much to do on the chassis and body.