Pioneer Diesel Locomotive Group

Work on Sherwood has been paused for the last two weeks while Barrow Hill was turned upside down for the steam gala. The team helped tidy up our area and covered over the roof of the loco to protect it from the inevitable volcanic ash falling out of the atmosphere from the steam locos. However, we were reminded why diesel locos did not mix with steam traction on BR, when we returned to find that a fine layer of rust had developed on any exposed steel surface including some of our polished cylinder heads. Our neighbours on 58016 were similarly dismayed to find several of their restored components afflicted by the acid rain.

Work resumed on the nose end, with completion of wiring in the instrument box and a quick test by Carl. The cover over the engine block was pulled back, and the top cleaned of oily gunge by Nathan and Matt – once the studs have been cleaned, the area will be primed before the liners are extracted, to minimise the amount of dirt falling into the crankcase.

Jacob has set up a production line in our workshop to clean various small engine components and got through six of the rockers. Cylinder head No 8 was prepared for valve lapping.

Rockers after cleaning

Engine block after cleaning

With the Barrow Hill steam gala approaching in 2 weeks, we have been racing to complete as many jobs as possible, so that our area can be tidied up. This has meant a busy weekend cleaning and painting the various bits lying on the benches and around the loco. This included the snail cowling for the blower motor that was refitted to the ducting in the nose with a new set of rubber seals. The field frame for the blower motor itself was restored and the internals painted in anti-track by Matt, while the armature and fan were delivered to Bowers for commutator skimming and balancing. One of the brush boxes was found to have a broken spring, so this may have contributed to the worn commutator profile due to lack of pressure on the carbon brush.

The tally on overhauled cylinder heads reached 7 this weekend, with some aching arms from lapping valves and spigot rings. The heads were queuing up to be painted by Matt and Adam.

Paul spent Sunday fitting the last of the resistor grids to the boiler room, and cleaning out the whole compartment of accumulated dust and muck. Carl continued with the rewiring of the instrument box.

We were pleased to see the 33/1 group in attendance with guest visitor JC from Swanage. After several hours on the charger and some replacement battery cells (ex 33035), 33 108 burst into life and did a quick revolution on the turntable to entertain the Roundhouse public and volunteers.

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!

Engine block after heads removed

B-bank heads were unbolted and lifted out of Sherwood this weekend. An initial inspection found that they appear to be crack free, which is a relief after the 50% failure rate on A-bank.

The top of the engine will now be cleaned off prior to pulling out the liners. In the meantime the heads will be steam cleaned and overhauled.

Cyl head being lowered on to scissor trolley

Carl has reconnected the fault lights at No 2 end and checked they light up correctly.

Nathan and Matt winding off the cyl head nuts with the torque multiplier

The Sunday mission was to reassemble the compressor for Sherwood, as the armature had arrived back from Bowers and the last few parts were restored during the week. A heat gun was used to heat up and expand the bearings so that they can be slid on to the armature shaft. Adam and Matt learnt the hard way that you have to be quick to avoid the bearing cooling and shrinking on to the shaft before it is in the correct position. Once this was rectified, the armature was reunited with the field frame and the end plates and seals refitted. Finally the motor was craned on to the compressor base and the original shims used to ensure correct alignment for the gear drive.

Carl moved into the closing phases of fitting a new set of switches and warning lights for the driver’s instrument panel, now enclosed by a newly fabricated box.

45105 was not forgotten this week, as the overhauled triple pump was given a final coat of gloss.