A while since the last entry...but no let up in the work going on...

 

26043 has seen most attention to the engine block where the damaged bores have been "belzona'd" to make them....well less damaged... Belzona is a very expensive high performance chemical metal, that's over £160 per kilo its extremely tough and will very very quickly blunt anything less than 60grit sand paper.

 

 

 

No6 Bore (closest the main generator) you can see the cavitation damage caused by 60 years of running an engine on water attacking both seal lands and working on the 3rd, this is prior to belzona being applied, this issue is not unusual in baby sulzers, because they have never been re-bored, class 33s and class 44s 45s 46s and 47s were all rebored, which meant the damage was less severe (but not eliminated) as the re-machined surface stood up better.

 

 

 

A layer of belzona applied and in the process of being sanded back to bare metal, the vast majority of the pits you see above are now filled, you have to sand back to bare metal because the belzona will not stand the pressure from the liner seals and will be torn away from the liner surface to the left you can see the belzona layer to the right you can see the finished side of it....all achieved with a cordless drill and flap brush, and takes on average 6 hours per bore! the black bag beneath prevents the majority of the dust entering the crankcase where if it was able to enter the oil system of the engine would cause severe damage to the oil pump. You are looking at the interior of the water jacket and despite being a 60 year old casting is in remarkably good condition, the same cant be said of the bore though and all 6 had this issue in varying degrees. Other present was fretting, this is where slight movement of the liner with the stroke of the piston causes movement and wears the bore leaving an inprint of the liner seals in the machine surface....this is exactly why the larger sulzers were re-bored to correct this, the baby sulzers being lower power generally didnt suffer this issue bad enough to warrant this work.

 

In an ideal world the block would be separated from the crankcase, and this bore would be built up with weld and properly bored back to the original specification......but the ideal world is rarely the world available to you.

 

So after a lot of time with a dead arm, yours truly has got the bores back to an reasonable condition....

 

 

time to put the liners back where they belong.

 

26043 has a 6lda engine....the 6 being the number of cylinders, when we took the liners out during the strip down, 4 liners ended being deemed beyond reasonable further use, if you had to they could have been re-used, but internal and external damage would have significant dampened the impact of the rebuild as such it was deemed appropriate to source 4 new standard size cylinder liners. Liners 5 and 6 were assessed as being in the best condition and were retained, liners 1 2 3 and 4 were rejected.

 

 

here we see liner 5, liner 5 unique in that it has a nylon fret band, these were added to combat the described fretting (movement in the bore) the idea was that the band was sacrificial (and cheaper to replace than the block) these fret bands are very common on 12LDA engines but less common on 6LDA engines, they a monumental pain in the backside, incorrect insertion of the liner means this band gets displaced and disrupts the liner seals and you end up with a leaking liner, and you have remove and start again. being an older liner you can see the damage to the seal lands, this looks worse than it is.

 

 

 

on the other side of the liner the corrosion is a bit more severe and has been repaired with belzona and carefully re-profiled.

 

 

Liner 6 again and original liner....non fret banded...but note the wear on the area covered by the fret band...again belzona repairs to the liner seal lands.

 

 

 

 

the brand new liners (non fret banded) slight surface rust from winter strorage, nothing a scouring pad wont sort out, the ring in the upper picture is called a soft iron ring, and originally it was the only "gasket" sealing the block and the liner on the upper deck, the idea is the liner crushes the soft iron to form a water tight seal.

 

 

originally as mentioned the soft iron ring was the only seal......however in the late 80s and early 90s this was proving to not be enough, damage and corrosion to the liner top deck mean that a new fix was needed, and this time railfrieght distribution were instructing depots to fit gortex to the liner sealing surface to give a better seal 26s never had this....but being a sulzer its still applicable. here we see the gortex fitted to the lip of the liner, this will be crushed into a water tight glob...when installed in the block.

 

Liners 5 and 6 being transported down on a modified trolley with the tackled used to "insert" them into the block. The flanged plate sits at the base of the liner and the two 1 inch diameter rods are passed down the interior of the liner to thread into the flanged block the, the large thick plates are then put on top.

 

 

No 6 liner with its new seals fitted and an illustration of the lifting tackle.

 

 

Another view.....underneath.

 

 

Hopefully the last time this liner see's daylight.

 

 

the block prior to liner insertion....the soft iron ring in place with hylomar for added "belt and braces"

 

No 6 liner....entering the block.....

 

 

The liner goes in so far and then sits on the liner seals.....the clearance between the liner and the bore is about .4mm normally the liners would be screwed down against the head studs by hand....but this risks crabbing the liner and damaging the seals and, beside we are lazy, so in this case a jack was used against the head studs to push the liner into its final position, the head when attached will firmly clamp the liner down.

 

 

you will have to turn you head to one side....but 12 hours later...all six liners have been installed. The four holes are for water flow to and from the cylinder heads.

 

 

the first 3 pictures are of various water pipes being re-painted, the picture above is the bogie retaining brackets...