Injectors

The Achilles Heels of earlier Ruston engines are the injectors.  These were of Ruston’s own design and made in-house.  Although they worked perfectly well, they were difficult to service and because they were only used on Ruston engines, there are now very few spare parts left.  Later Ruston engines used CAV injectors, as did most small and medium-sized British-made diesel engines, and hence replacement CAV injector parts are more readily available.

The Ruston Mark 37 Injector

A Ruston Mark 37 Injector from a VPH Engine

The picture shows the components of a Mark 37 Injector :-
A    Plug (overflow pipe connects here)
B    Sealing washer
C    Needle Valve Stop
D    Injector Spring
E    Spring Washer
F    Spring Housing
G    Nozzle Assembly
H    Injector Body with inlet filter
 

The injector nozzle is the most stressed part as it is in direct contact with the hot combustion gases.  It is also very critical as it must produce a spray of very fine droplets of diesel to obtain correct combustion without excessive smoke.  It contains very small holes, which can become blocked, is subject to erosion, and the needle valve and seat become pitted leading to dribbling and poor combustion.  The nozzles are designed to be serviced at intervals and replaced when necessary whereas the rest of the injector will normally last the life of the engine.

The earliest Mark 37’s had a nozzle that was separate to the needle valve and guide and was difficult to line up correctly.  Subsequent injectors, including those on Queen Anne, had a combined nozzle, needle valve and guide which is a much more satisfactory arrangement.  The nozzles are machined to very high tolerances and must be kept scrupulously clean.

The injector pressure is important, and for the Mark 37 should be 3000 psi.  Other makes of injector have a screw device to vary the pressure on the injector spring, but with Mark 37s shims have to be placed alongside the spring washer (E), and this involves repeated assembling, testing and dismantling until the correct pressure is reached.

The Water-damaged Nozzle

The picture shows a nozzle that was badly pitted due to water entering the cylinders when the loco was abandoned.  It is obviously a write-off.  Unfortunately there seems to be no replacement nozzles to be found anywhere, in spite of contacting various specialist companies and Ruston experts.

The Wrong Nozzles

When the injectors were dismantled, it was found that the wrong nozzles had been fitted at some time in the past, presumably at Longmorn.  There was one of the correct type (VRH) and three for a VPH engine, which has double the cylinder volume.  The VRH nozzles have 3 x 13 thou holes and the VPH nozzles have 4 x 16 thou holes – quite a difference!!!

You can see the wording FVPH on the left and FVRH on the right.  Also showing the needle valve.

The engine obviously ran with VPH nozzles, and as VRH nozzles are unobtainable it was decided to use VPH nozzles in all injectors.  This meant replacing the VRH nozzle and badly pitted VPH nozzle.  Of course, VPH nozzles are unobtainable too, so it was decided to “borrow” nozzles (also in poor condition) from the out-of-use Ruston 0-4-0 DM shunter, which has a 6VPH engine.

Reconditioning

Two tools were made to aid in dismantling the injectors.  A simple removal tool screws into the Needle Valve Stop (C) and pulls it and the washer (B) out.

Simple Dismantling Tool

The orientation of the injector sprays is important, and an inscribed line on the nozzle must line up with a similar line on the injector body.  A special tool was made to allow all the injector internals to be lined up before sliding the injector body over.

The Assembly Jig

Injector Internals Mounted on the Assembly Jig

The injectors were reconditioned by Rayner Diesels in Newbury.  While they normally service modern diesel fuel injection equipment, they have many years expertise and still have the equipment and knowledge to service older injectors.  For injectors in such a poor state, renewal of the nozzles would be the normal solution, but in the absence of spare parts the nozzles had to be brought back to life.  The needles were seized in the nozzles and needed to be warmed up gently to soften the congealed diesel oil.  The valve seats were badly pitted and needed carefully lapping in with very fine grinding paste.  Most of the nozzle holes were blocked up.

The sealing washer (B) is a special shape as it needs to seal both the needle valve stop (C) and the injector body (H) against the full injection pressure.  These washers can only be used a limited number of times, so some new ones were machined out of copper bar.  Rayners were short of one good washer, so one of the injectors suffers from back-leakage until we have made and fitted a new one.  This should cure the white smoke which is currently being generated by No. 1 cylinder.

If anyone knows of a source of Ruston Injector Nozzles, please let us know.

Engine Started!

On Saturday 11th March 2017, the engine was started for the first time in about 35 years.  It took took a while to get all air out of the fuel system and get all four injectors firing, but it seems to start reliably now.  From cold, you need to use the "excess fuel" device, but once the engine is warm it starts without this.

The following short video clips record the event :-

First run

Running continuously now

Spragging Gear

Spragging Gear

Spragging Gear is the name used by Ruston to describe the exhaust valve lifting mechanism that allows the engine to be turned without compression.

The spragging gear helps in starting the engine.  The crankshaft can be rotated much more rapidly (using the starter motor or by hand) if there is no compression.  When the gear is released, the momentum of the flywheel helps to maintain speed while the engine starts.  If the injectors or pump are worn, the initial rotation will prime the injectors and ensure that fuel is being delivered when compression begins.  In favourable conditions, it might be possible to start the engine by hand using this method, although it would require considerable stamina and probably the use of both winding handles (located on either side of the loco).

Each cylinder head has a side cover which carries the spragging gear.  A cam is rotated through 60 degrees and lifts an operating rod by about 80 thou to push against the exhaust valve rocker and open the valve.  The following diagram from the Parts Manual shows the general arrangement.

Spragging Gear Parts for a Ruston 4VRH

Because the gear spends most of its time inactive, it appears to have been under-designed by Ruston & Hornsby.  The cams had become very loose in the covers (there is no effective lubrication for the bearings), and there was a lot of wear in the operating mechanism.  Also the operating levers on each cam had been pinned at inconsistent angles, so the cams were not properly aligned.  The sprigging gear should be set so there is a 25 thou gap when the gear is inactive and the exhaust valve closed.  However because of wear, there was 40 thou of slack, so proper setting was impossible.  In fact, prior to restoration, the gear had been adjusted to a large gap, effectively putting it out of use.

The bearings in the covers were bored out, fitted with bronze bushes and reamed to size.  The bushes have a groove to take an O-ring seal and an oil hole to allow engine oil to drip through.  New cams were made as the old ones had worn bearing surfaces and worn cam profiles.

Cover with new bush.  New cam on left, old one on right

The operating levers for cylinders nos. 2 and 3 have a slot in the end to allow for slight differences in height.  However, these slots had become worn, so it was decided to make new ones to remove the slack in the operating mechanism.  The long lever on cylinder no. 1 had a crude stop on it to define the two positions (30 degrees either side of vertical).  This had become worn and imprecise, so a new rod was made with an improved design for the stops.

Two new levers.  One old lever.  Two refurbished levers.

Once the improved gear is in place, another attempt will be made to start the engine.

Top view of the engine with new Spragging Gear in place.

Filters

The original Ruston 4VRH engine had mesh/felt filters for oil and fuel.  These filters are not very effective and are messy to strip and clean.  A decision was made to replace them with modern cartridge filters, which are much more effective and because they are easy to change they are more likely to be changed regularly.  An additional water trap was installed on the fuel line as fuel quality cannot always be guaranteed.

New Water Trap and Fuel Filter

In order to make things as original as possible, the upper parts of the filter brackets were retained and adaptor plates made to accommodate the new screw-on filter elements.  The Ruston manual calls for an SAE20 or SAE30 detergent oil for the engine, and the use of a modern oil filter means that modern oils can be used – in this case Morris ring-free XHD30.  Diesel engines generate quite a lot of carbon past the rings and into the sump, so a good detergent oil keeps this in suspension and prevents sludge building up.

The new Oil Filter

Radiator & Fan Belt

The radiator consists of three parts; the upper tank (steel), the core (steel) and the lower tank (brass), which are bolted together with rubber gaskets.  Fortunately the steel core seemed to be OK after cleaning up.  New gaskets were made and the radiator tested for leaks.  The bottom tank was found to be leaking around the bolt holes.  This was traced to hairline cracks in the brass, and these were repaired by brazing.  The inlet and outlet pipes were badly corroded inside, and were not particularly well soldered. so these were replaced by new stainless steel pipes.

Subsequently the filler pipe started leaking around its joint with the upper tank.  It is vulnerable while the radiator cowl is not fitted and had probably been strained.  It was found to be rather crudely soft-soldered to the tank with only a steel wire ring underneath for support.  Because the pipe itself was badly corroded inside, it was decided to replace the pipe and secure the new one using large brass nuts and sealing washers.  The original filler cap was worn and would only engage on a few threads, so a new one was machined out of brass.

The original reinforced rubber hoses were replaced with new polyurethane hose, which is much more durable.  It was decided to incorporate a water level indicator.  This consists of a standard steam loco “gauge glass” tube contained in a machined brass holder and has been fitted next to the thermostat.

Radiator, water gauge and fan belt

The fan belt has been fitted and tensioned.  The belt is of the “link belt” type because it would not be possible to fit a standard belt without removing the bevel gears on the front of the crankshaft that comprise the hand winding mechanism.  In any case, the pulley profiles are of an obsolete type, and modern belts would not fit properly.  Indeed modern link belts are of the wrong profile too, but some suitable “Brammer style” link belt was obtained from Stationary Engine Parts.

Gearbox and Transmission

Gearbox and Transmission

Thanks to the generosity of the Friends of Broomhill Station, we have received a donation that has enabled us to buy a new drive chain.  Fortunately 1.5 inch pitch heavy-duty roller chains are still available.

The new drive chain

 The power from the engine is taken via a flexible coupling next to the flywheel to the Ruston patent constant-mesh gearbox, which has 3 speeds.  This feeds the integral transfer gearbox, which moves the axis of rotation 90 degrees and is equipped with a forward-neutral-reverse lever.  The output shaft, running across the gearbox, has a sprocket at each end driving the two axles via roller chain.  The axles are suspended from adjustable-length swinging arms, whose pivots are approximately (but not exactly) in line with the transfer gearbox output shaft, so that the chain tension does not vary too much as axles move up and down.  The adjustable swinging arms allow wear in the chains to be taken up.

The new chain in place, before adjusting the tension

The Ruston patent gearbox was designed in 1931 and used in almost all narrow-gauge and the smaller standard-gauge shunters with chain drive.  It proved to be a robust and reliable transmission.  Each gear ratio has its own friction clutch, and a system of interlocking selector levers ensures only one clutch can be engaged at a time.

It was noticed that the gearbox input shaft on Queen Anne had some side play, so the top gearbox cover was removed (it weighs 3 hundredweight).  The input shaft runs in the upper cover supported by a ball bearing and a caged roller bearing.  The ball bearing was not the original, and at some time in the past the shaft had been rotating inside the bearing.  The roller bearing also seemed a bit noisy, so both were replaced with new British-made bearings.  The worn shaft was built up with weld and machined back to the correct size.  An extra rubber shaft seal was also fitted to prevent dirt entering the ball bearing.

The gearbox was also given a good clean out.  Because it uses friction clutches, a lot of grey sludge is formed as the friction linings wear.  Also the flange that joins the two parts of the casing had been damaged in the past and a corner bolt-hole had broken.  A crude bracket held the broken part in place.  The broken pieces were welded back using an arc welder and pure Nickel rods.

General view of the gearbox

The gear selector mechanism bolts onto the side of the gearbox.  A roller on the bottom end of the lever depresses one of three tappets that select the appropriate gear.  The roller and its pin were badly worn (their position means that they are unlikely to get any lubrication), so initial thoughts were to make replacements in silver steel and harden them.  But after some thought it was decided to use a Cam Roller which is a special sealed ball bearing designed to be used for this purpose.  A new pin was made to hold the roller in place.  After fitting the roller, it was found that the gear lever could easily be made to spring back into neutral – it would be very painful to be hit by the lever as it springs back.  The roller is designed to go over “top dead centre” and be held in the engaged position by the tension of the clutch springs, but on investigation the tappets were found to be slightly worn so that the roller was barely going over top dead centre.  Dressing the tappets with an abrasive flap wheel restored the correct profile and resulted in firm engagement of the gear lever.

The original worn roller

The new Cam Roller

The Cab Floor

The cab floor consists of several steel panels which bolt together.  The original design used nuts and bolts in some places, which meant access to both sides was required to remove sections of floor – essential to gain access to the gearbox etc.  So it was decided to ensure all fixings were via countersunk screws that fitted into tapped holes in the supports.  Stainless steel screws were used to prevent them from seizing up.

Some of the floor panels and the fuel tank after painting

While parts of the floor were supported on brackets on the chassis, the edges were originally supported by the cab sides, which in turn were attached to the chassis by a metal plate which was a rust trap.  This arrangement was re-designed to use four pillars rising from the chassis at each side to support the floor close to the edge.  Not only does this produce a more rigid floor, but the floor can now be a solid stand-alone platform without needing the cab to be present.  Also the rust-trap at the bottom of the cab sides can be eliminated and be replaced by a simple stiffening bar.

View showing the 4 vertical pillars towards the back

 The floor panels were bolted down with rubber pads underneath to reduce vibration.  In future it should be a simple matter to remove a section of floor for maintenance purposes by undoing a few stainless steel screws.

The outer floor panel is screwed to the 4 pillars

Latest News

Here is a recent photograph showing the cylider heads in place and the reconditioned injectors fitted.

A view of the engine

New Owner's Plate, Nameplates etc.

Owner's Plate

If you look at the black-and-white photograph at the top of the blog, you may be able to make out a small sign fixed to the lower bodywork of the locomotive.  After purchasing a full-resolution copy of the photograph and blowing it up, it can be seen to be an owner's plate.

Detail of the side of the locomotive in 1977

It reads "Ms. Longmorn Glenlivet Distillers Ltd." - the "Ms." stands for Messers.  The plate is long gone, but by measuring the distance between the empty bolt holes on the locomotive (15 inches apart) it is possible to work out the size of the lettering etc.  A desktop publishing program (Scribus - it is free open-source software) was used to produce artwork to match the original :-

Artwork for the Owner's Plate

Kingussie High School has been very generous in allowing us to use some of the equipment in the Technology Department, namely the CNC router and the casting furnace.  The artwork was used to produce a pattern in MDF using the CNC router.

Casting patterns in MDF

The pattern is placed in a wooden frame known as a flask, and oil-based moulding sand compacted firmly around it.  The easiest and quickest way to cast something like this is to use an open mould, and simply pour molten metal (Aluminium in this case) into the flask after removing the pattern.  However, the quality of the resulting castings was not very good.

First attempt at casting

The metal has not flown fully into the lettering, and shows a meniscus instead of sharp edges.  The reason for this is that there is not enough pressure to force the molten metal in - the pressure is only about 15mm of Aluminium.  The answer is to take more time and use a two-part flask.  The pattern is first placed in the lower part (the drag) and packed with sand.  It is then turned over and the upper part (the cope) placed on top.  Pipes are fitted to produce risers for the molten metal to flow in and out.  The cope is then packed with moulding sand and the cope is lifted off the drag.  The pattern and pipes are removed, everything is cleaned up and the cope is re-fitted.  Molten Aluminium is then poured into the flask until it appears at the vent.  The greater height of metal gives a higher pressure - about 100mm of Aluminium.  The result is much crisper definition.

The Drag and Cope ready for pouring

Pouring the molten Aluminium

Cope and Drag separated after the metal has solidified

Nameplate before removal of the sprues

The final nameplate cleaned up and ready for painting

Nameplates

The same process was used to make the nameplates.  The artwork was based on the font used in the original Queen Anne advertising panels, and truncated corners were also used for this reason.

The finished nameplates

Worksplate

All Ruston locomotives have a worksplate with the works number of the locomotive.  Unfortunately, this had been stolen by souvenir hunters while the locomotive was dumped behind Aviemore Speyside station - or it may have been removed for safekeeping, but if so where is it?  The lower front cab panel shows the marks where this and other instruction plates were originally.

Location of missing plates inside the cab

Fortunately, a picture of a worksplate from a Ruston 48DS of similar vintage appeared on an auction site, so the artwork could be reproduced.

The technique for producing the worksplate is quite different and involves etching the design onto a piece of sheet brass.  The artwork is produced in negative format - that is black background and white letters.  This is then printed onto a transparent sheet using a laser printer.  The brass blank is covered with UV-photosensitive resist.  Spray-on resist is no longer readily available but self-adhesive film from China is very cheap (even including postage).  It takes a lot of practice to apply the film without air bubbles, but it can be done.

The negative is placed over the resist-covered brass plate and exposed to strong sunlight for 5 minutes (not much of that this year).  Afterwards the unexposed resist is washed off with some of the developer powder dissolved in water (the instructions are all in Chinese).  To etch the brass away, Ferric Chloride is used.  Fortunately an etching kit designed for making your own printed circuit boards and dating from the days of "Practical Electronics" magazine was to hand.  The etchant had not gone off, and after an hour or so (to get a really deep etch), the plate was removed and cleaned.  A proprietary brass blacking solution was used for the background.

The finished worksplate

The Size, Class and works number will be stamped onto the plate at a later date.

As can be seen from the picture of the cab panel, there were also 3 rectangular plates inside the cab that gave instructions on the driving the locomotive.  The text for one of these has been recorded from an online photograph, and the text for the other two will be investigated.  If anyone knows who has the originals, please let us know.

Colour Scheme

The choice of livery for a locomotive can be controversial and the cause of much heated argument among railway enthusiasts.  Hopefully the proposed livery for Queen Anne will not stir up too much trouble.

As can be seen from the image at the top of the blog, QA has panels advertising Queen Anne whisky on a strange beige coloured background with white lining.  An earlier colour photograph shows the same adverts against a greenish background, but with subtly different lining, so the background must have been repainted at some point.  It is likely that the locomotive never ran at Longmorn with this colour scheme, but was painted specially for delivery to the Strathspey Railway in 1980.  QA was delivered to Longmorn painted in green with white lining and white buffers, and ran in this state until 1980 when the distillery’s private rail network closed.

Pure Ruston

While many industrial customers for Ruston & Hornsby’s locomotives would ask for their loco to be painted in their company colours, it appears that the distillery did not specify any such colour scheme, so the locomotive was delivered in R&H’s own standard livery at the time (1948).  This consisted of “Ruston Green” (also known variously as Lincoln Green or Verdigris Green, BS381C Shade 276) on most of the locomotive and inside the cab with white lining, red buffer beams (exact shade unknown) and a black cab roof.  There was a Ruston & Hornsby crest on the side of the cab, and RH monograms inside the cab.  The green background at the top of this blog is "Ruston Green".

There are sufficient black & white photographs of the locomotive at work at the distillery to re-create the white lining.  Some “paint archaeology” has exposed the original crest on the cab sides so that its size and position could be determined.  No colour photographs of the locomotive at work have been found so far.

The original Ruston crest on the cab side exposed

Some original Ruston transfers have been purchased for the cab

There are quite a few Ruston 48DS locomotives in existence, although only a few are in working order, and none are in pure Ruston livery.  This is another good reason to restore Queen Anne as closely as possible to its as-delivered state.The locomotive never carried a number or name while at Longmorn, but since arriving at the Strathspey Railway it has been known as Queen Anne because of its advertising panels.  For this reason it has been decided to cast Queen Anne nameplates to be fitted on the upper bonnet of the loco.  For those people wishing to take photographs in completely “Pure Ruston” condition, they could be removed temporarily in exchange for a £20 donation to locomotive restoration.

The Queen Anne advertising panels have been photographed and reproduced using desktop publishing software.  The artwork is in the form of actual size print-ready PDF files, so could easily be printed as self-adhesive vinyls or magnetic sheets at fairly low cost.  So it would be possible to temporarily create something approaching the “Queen Anne” of the 1980s if required.

Original Queen Anne advertising panel

Reconstructed artwork using best-match modern fonts

Hopefully reverting to the original livery will appeal to those who would like to see an accurate restoration of a distillery shunter as well as fans of Ruston & Hornsby locomotives.

Latest Updates

The reconditioned cylinder heads have now been put back on.

The Ruston 4VRH engine on 16th July 2016

The right hand side of the engine on 16th July 2016

Also, the GNSRA article on Queen Anne can now be seen on the "Queen Anne History" page.

Latest! Cab sheets arrive.

While the other posts on this blog have been recapping what has been done in the past, this post relates to progress right now (July 2016).

It would be feasible to make new sheeting for the cab in-house by plasma-cutting, hand-finishing with an angle grinder, marking out and drilling holes.  However this would require a lot of time and effort, and it would be difficult to get really straight vertical edges where the sides are joined on with angle iron.  It takes much less physical effort to measure up the old cab sheets and produce drawings in AutoCad.  CAM (Computer Aided Manufacturing) can then produce new cab sheets with a high degree of accuracy an no hard work!

A CAD drawing of the cab sheets was produced after careful measurement of the old metalwork.

Upper & Lower Cab Front CAD Drawing

There are three main ways of producing metal sheets using CAM; plasma, laser and water jet.  Plasma cutting is the fastest, but is less accurate and requires some finishing.  It is not very good for cutting small holes (eg. 10mm), but you can use it to produce a shallow cross to mark hole centres.  Laser cutting is very accurate and requires little finishing.  It is also good for fine detail and holes.  Water jet cutting is often used for cutting thick materials, but is also good for sheet metal.  It is a bit slower than the other methods but very accurate.  Because there is no heat-affected area around the cut, there is no distortion and no finishing is required.  Water jet cutting uses a very fine jet of water at 60,000 pounds per square inch pressure, either with or without an abrasive (depending on the material).

Initial thoughts were to use plasma or laser cutting, and there are companies that can do this in Aberdeen and Glasgow.  However a recent volunteer at the locoshed is a machinist at Forsyths in Rothes.  While Forsyths traditional market was making and maintaining whisky stills, they also do specialist work for the oil and gas industry, and have a water jet cutter.  Jim took away a memory stick with the AutoCad drawings, and most unexpectedly a couple of weeks later the new cab sheets arrived at Aviemore sheds!

Upper rear cab

Lower front cab

Lower cab sides

The finish is truly amazing, and the cut edges are perfectly straight with no burrs.  They arrived as bare metal, so were immediately sanded and professionally painted with red oxide primer.  It is important to apply primer carefully (avoiding sags and brush-marks) to make life easier when applying the final coats.  Otherwise it would require a lot of sanding down to obtain a good finish.

Detail showing clean edges and neat holes

This slot (for the spragging lever) shows the precision of the cutting process

Lesson Number One

Assume nothing.  There are 4 "identical" handrails on the sides of the cab, and on the CAD drawing the fixing holes are all the same distance apart, based on the measurements of one old sheet.  However, it appears the handrails were not accurately made and differ in length by a few mm, so the original cab sheets must have been drilled to fit the handrails.  Some dressing of the holes will be required, but it won’t be noticeable when the handrails are fitted.  This is the first job using CAD/CAM, but there can be no excuses – what you get is only as good as the drawing!