It was back to the main event again this week with work progressing on all fronts with Sherwood. The front cab bulkhead was glossed and fitted out with new insulation panels. Carl continued fitting out the instrument box with a set of restored bulb holders.
Now that the compressor is finished, Matt and Jacob dismantled the traction motor blower motor, which turned out to be none too soon. The brushed were almost down to the pigtails, and the commutator is badly worn. Both bearings were extracted for renewal, and the armature loaded up for despatch to Bowers. As before, the field frame will be cleaned, tested and restored by our team at Barrow Hill. Also restored and now in undercoat thanks to Nathan are the fan, snail cowling and motor stand.
A day was spent steam cleaning off black gunge from the six removed B-bank cylinder heads, transferring large quantities of the substance to the operator. The heads were first left to soak in a mix of paraffin and diesel, steam cleaned off, and then coated with strong sodium hydroxide solution to dissolve the remaining grease and carbon. After a final blast with the steam cleaner, the process revealed six heads in good condition, and no signs of cracks around the valve seats. The first head was duly put through a day of laborious valve lapping, until both valve faces and valve seats were free of pitting and perfectly matched. So thats four down, eight to go!