Thursday, 15 October 2015

Playing Catch Up: Part 1

There's an underlying flaw to blogging that has well and truly done for me this year: the more you do, the less time you have to write about it. 

Photo: Graham Richardson, Plymothian Transit
Since we first became manacled together (can you believe, almost six years ago now), this has been the busiest year for 270 KTA - and for me personally, the most intense.

Now, this is not just an excuse for the lack of activity on 270 KTA's blog over the past ten months, but also for the length of the posts you're going to have to endure if you want to catch up. And both our friend and I sincerely hope that you do...

To spur you on, there are the usual dramas that have become the staple of this blog over the years - like a 450 mile round trip to fetch a water pump for fitting overnight; like barricading-in a Police car at the entrance to Morrisons' car park in Bath; like spending £10 on a magnet to retrieve an escaped nut, only to find it's made from brass. Those sorts of things do you? There are also many highs, and many pretty pictures to enjoy along the way.

Let's pick up where we left off. I believe you wanted to know how to change a head gasket?

This pair'll show you. Back in February, Sheppards Junior and Senior set about solving 270 KTA's determination to mix oil and water. You'll recall that huge amounts of coolant were being deposited in the sump, a typical sign that the head gasket (which provides a seal between the top of the engine block and the head of the engine, and through which water travels) had failed. Indeed it had, though as you'd expect from our devious friend, that turned out to be only part of the story...

You can see from the scarring on the head (above, upside down on the bench) where coolant had been passing from the water jackets through the failed gasket in two places, and into the cylinders. The gasket certainly did need to be replaced, but the head, block and piston liners also needed work to ensure we'd get a good seal on the new one. The opportunity was taken for a full decoke, and many happy hours were spent grinding in the valves with our trusty 'gob-stick' and a tub of Chemico grinding paste that's older than I am. 

10 litres of Jizer proved to be almost enough for the many days of cleaning necessary to remove the milky white emulsion which had invaded every part of the system. Having installed the new gasket and refitted the head (and realised that a Sheppard will break long before a torque wrench), we then set about tackling the inevitable nine-hundred and ninety-nine jobs allied to the one we'd set out to do - brazing up a crack in the fuel bleed off pipe, sorting out the air cleaner, retrieving that aforementioned brass nut from the gap between the block and the chassis - all those little unexpected things that take so much time. 

No wonder that Jizer wasn't the only fluid consumed in volume...

Another of the nine-hundred and ninety-nine jobs was an old weakness of the Albion EN250 engine, whose rocker-cover is an aluminium casting with four fixing nuts across its centre. With the engine mounted on its side (had you never noticed?), it's necessary to get a good seal when fitting the cover, otherwise oil will simply drain to the ground through any gap. Over the years, the tendency has been to over-tighten the nuts, therefore bending the rocker cover and... oh dear - aluminium castings are so fragile look. When we took it off, 270 KTA's rocker cover was found to be both badly bowed across its length and cracked in several places, and would never achieve a seal if we put it back like that.


Just as well we have some clever friends in our midst. Not only is Alex Heath a very skilled precision welder (yes - aluminium can be welded), but a creative technician too. Above is his ingenious method for correcting the banana-shaped sides, a specially manufactured jig, used to vary the tension across the rocker cover as it was heated and cooled. Huge amounts of work went into getting this right, and we're very grateful for his help and skill.

By early-April, we heard this sound again - for the first time in 2015...


... but all was not as good as it sounded. After the shortest of test runs it was clear that, while necessary, the head gasket change hadn't completely solved the problem. Still, coolant was somehow finding its way into the sump, and with our traditional Penzance Running Day deadline looming, the pressure was on to find out how. 

Your scribe asked himself what might have caused the head gasket to fail in the first place, and suspicion fell on the water pump. This is the unit, driven by the engine, which pumps coolant around the system to prevent it from overheating. If it failed, the engine would run hot and very soon the head gasket would fail. Consulting the Albion diagram, it's clear that when the water pump is in good working order there is no direct route for coolant to pass through the unit into the engine. But if something wasn't right inside....

Bingo! This extraordinary sight is the impeller ('P' in the diagram above) which should force the coolant around the system. Dramatically sheered from its drive shaft, it clearly hadn't been doing a lot of impelling for quite a while, and was probably therefore at the root of the head gasket failure. Worse still, with no fixing ('R') at the end of this shaft, the innards of the water pump were free to float around - including, crucially, the rubber gland ('N') which would normally prevent coolant escaping to the engine. If only we had another water pump...

Oh! Here's one, together with somebody else who's owed a drink or two by 270 KTA... 

With the Penzance time-bomb ticking, Conductor Farley (more on whom in Part 2) managed to combine a work commute from Exeter to London and back with a stop at Maidenhead station. Here, he was met by Colin Billington and a fully functioning waterpump, which he'd kindly had overhauled by Graham Green while our courier attended his meeting. A splendid team effort.

This was on Tuesday; we were due in Penzance on Saturday, so having received the goods your scribe wasted no time in getting his overalls on. Overnight, I fitted the pump, flushed the system and changed the oil for the fourth time in as many months. A test drive at dawn suggested that all was well this time, and I ventured to work in the absolute certainty that we'd probably cracked it - or might have done.

Now, there's something I haven't told you about thus far. In parallel with Gasket-gate, a second work front had been slowly progressing since last Autumn, and had itself run short of time. That's why, days before the Penzance deadline, 270 KTA's interior looked like this:


I know, I'm an idiot. You'll remember from here that I'd taken the Winter opportunity to swap some seats and 'quickly' paint the frames. Well, just as Gasket-gate grew into nine-hundred and ninety-nine jobs, so too did this lil' lick of paint. 

While the seats were out, I'd decided to repaint the headlining, which had been done (very badly) some years ago and really did look tatty. You can see what a difference it makes. The light shade (a bit more creamy in real life than it looks here) is much closer to the original colour of the headlining, and really lifts the whole appearance internally.

Having discovered the ease with which a spectrograph can match paint colours from swabs of rexine, I decided it would be churlish, while the seats were out, not to repaint the walls into their original shade of green... and on I went, giving myself a huge number of different loose ends to tie up at the last minute. 

Optimistic idiot. And yet...


... we made it. We're reminded of this blog's mantra of old (well, actually it belongs to Frederick Douglass, who first said it in 1873): "If there is no struggle, there is no progress". And so this year's Penzance Running Day seemed sweeter than ever before - not that 270 KTA has a good record on that score....

The sun shined throughout, the sea glistened. And fortunately, that was the only ocean we saw that day. After a 250 mile road test, and some of the most punishing routes of West Cornwall, I was satisfied that we'd finally solved the oil-water issue: my dipstick was mercifully un-milky once again. What's more, the de-coke and head gasket change have combined to improve the performance of the engine, which is noticeably more tenacious on hills. Time to celebrate with an ice cream...

Ah yes - that reminds me. Notice anything different (aside from Conductor Page's yoof cut and the unusual sight of me devouring anything other than a light green salad)? No?

In that case, time for a quick competition: Spot the difference. 

To the right you'll see the three main styles of fleetname carried by the Western/Southern National SU coaches. 

Style 1 was carried by all when new, and was a gentle chrome yellow in colour (not gold, a common misconception in preservation), with serifs on the letters, black outline and variable width of uprights and horizontals within the letters; 

Style 2 arrived in the late 1960s and was a much brighter colour, almost orange-yellow, much bolder, no seriffs and with only subtle variation in width of the stems - a good number of SU coaches had this style applied on repaint;

Style 3 was a bright yellow, think block, generally with black outlining tough not always - this wasn't widely used across the fleet, and to my knowledge only one SU coach ended up with it in service. (408 [922 GUO], since you ask...)

270 KTA carried style 1 until 1970, when style 2 was applied during its tenure at Taunton. In preservation before my time, a version of style 3 was applied in thick vinyl (the originals were thin varnish transfers), and have offended my eye ever since. 

Ultimately I intend to reapply style 1 to represent 270 KTA's time at Trowbridge in 1968-70, but those are transfers to save until repaint. To allow me to rest in the meantime, I had a set produced in style 2 as a little reward for spending almost every waking hour working to get 270 KTA ready for the 2015 season. 


Fittingly, I stayed up until 3am and applied them the night before Penzance...

'Playing Catch Up' To be continued...

3 comments:

  1. Phew ! I'm puffed out, reading this.

    Keep up the good work.

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    Replies
    1. Good man, Petras. Breathing like an Albion EN250!

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