It
is surprising how long assembly takes. All of the small jobs, threaded
holes, small details or finishes that have to be added to a part to
complete it. It is always tempting to rush ahead and get the engine
running on air or steam without completely finishing the mechanical
parts. I try and make everything first then assemble it to the main
part of the engine.
View
of the HP slide valve, cylinder now fixed to the boiler! : Note the
size of the LP steam passage!
The
flywheel was a very nice fit on to the crankshaft. I did not want
to distress the crank while fitting the flywheel so I decided to heat
the flywheel up to allow it to slide into position. The machined key
seat for the flywheel had to be lined up during assembly to allow
the key to be fitted later. To align the key slots I made up a small
cube of steel this was adjusted so that it would slide the complete
length of the key slot in both the flywheel and the crankshaft.
The
flywheel was warmed using a fairly large propane torch, the flame
was moved round and over the surface to allow gentle expansion of
the whole area without distortion. When hot. the flywheel was laid
down onto two wooden blocks that supported the flywheel off the ground
and to the correct and final resting place. The small alignment cube
was inserted into the flywheel key seat followed by the crank. The
crank inserted easily due to the heat in the flywheel.
Gaskets
were made from 1/32" graphite paper for the steam chest and cylinder
covers. The cylinder had to be positioned and lined up correctly with
the con rods and with the centre line of the boiler (crank). To do
this is a lot of messing around. I fitted the pistons to the crossheads,
con rods etc to the engine. Rotating the flywheel allowed the cylinder
- Stroke position to be found. I have allowed a total of 1/32"
mechanical clearance & 1/32" for the gasket paper for the
front cylinder cover when the engine is cold.
When
the engine is steamed the boiler expands with heat and pushes the
cylinder forward about 0.080". This has to be allowed for during
the design of the piston length to allow clearance of the rear cover
when hot. The cylinder was aligned with the boiler (& crank) centre
line using an engineers spirit level. The type used for machine tool
installation. The boiler was drilled and threaded 1/2" BSF (nice
thread) to secure the cylinder. So how do you seal the boiler and
cylinder? I have tried using high temperature silicone sealant from
Screwfix. This product has a working temperature of up to 300 degrees
centigrade. Hope it works!
View of
the valve gear swung back out of the way
Valve
timing on a large engine can be a trial. I find it easier to find
top dead centre (TDC) for the crankshaft then remove the connecting
rods to allow the engine to turn easier, especially if the piston
rings have been fitted. To find TDC I use a dial test indicator (DTI).
Place the DTI close to the limit of crosshead travel. fine adjust
the DTI and crank position so that you can measure the last five thousands
of an inch travel. Make and attach securely a position indicator at
the outer edge of the flywheel. At each position either side of TDC
mark a small line on the flywheel outer edge. TDC is midpoint of the
two marked positions. I usually cut a small notch on the inner edge
of the flywheel with a junior hacksaw at TDC. This secures a permanent
record for future use if required!
Set
square clamped to the horn plate, align the top edge for TDC positions
Valve
timing is then easier, I use a small spacer bush on the eccentric
bolts to allow me to remove and fit the rear half of the eccentric
quickly. During the timing operation the eccentrics are only secure
by a enough thread to fill half a nut. With the TDC mark aligned move
the eccentric and observe the position for the slide valve. Adjust
the valve to be open by 0.010" at TDC is recommenced for the
Big Mac when the reversing lever is in the running position, Rotate
the flywheel, observe the valve opening position at the other end,
if incorrect try centring the slide valve. Several iterations of this
in both forward and reverse are required to get the timing pretty
good. Good design practice should allow both forward and reverse valve
settings to be the same but! If needed, optimise for best timing in
the forward direction, this is what you will be using most of the
time. Both the HP & LP valves need to be accurately set
Home
made disposable ring clamp!
The
piston rings were fitted to the pistons, home made ring clamps were
made from a small thin (0.012") strip of stainless steel and
jubilee clips. This works quite well. The jubilee clips can be unscrewed
completely to remove them from the piston rod.
The
crosshead trunk guide's are bolted to the wayshaft bracket from below,
two fasteners in each guide. Getting the distance between the trunk
guide and wayshaft correct requires the addition of packing and shims.
I made the packing from 3mm mild steel plate. This was ground to the
correct thickness using a surface grinder. This allows a very rigid
connection to support the trunk guide from flexing when pulling hard.
The
5-7/8" LP pistons fit easily!
Following
the completion of the valve timing all of the boiler washout holes
were plugged to seal the boiler for testing on compressed air. I have
two small compressors. Both of these were connected to the engine
for the air test. The engine ran well on compressed Air. Moving the
reversing lever back to mid position made the engine notch up as expected.
It is so nice to see the engine run after such a lot of hard work!
Update,
April 10th 2004 : To Steam or not to Steam, that is the question?
Having
got to this stage it is quite a task to make the right decision, will
I run the engine in primer for a steam test, a whole season? What
would a steam test do? where will it get me? Lots of questions, possibility's.
I reckoned the following, if I steam test the engine I would probably
only run it once or twice to make sure it runs well, it should run
better on steam than it did on air. Steaming the engine would get
the engine coated in oil and soot, this would get baked on to the
engine, painting would be a lot harder due to the extra cleaning.
I talked this through with steaming friends and concluded it will
be better to paint the engine. The engine will be finished when steamed
for the first time.
Belly tank
internal coated with black bitumen paint
I
painted the inside of the belly tank with black bitumen paint to seal
it form leaking. This is quite a messy task. The lack of ventilation
in the tank causes a very slow drying time. The inside of the tender
water tank was also painted. I made a list of items that needed to
be done before steaming or painting. It is surprising how much time
the little jobs take, some of the little jobs were in fact quite big.
I needed to get the wheels riveted. Allen offered to rivet them using
the traditional hot riveting method. To speed things up I decided
to get them spun riveted. this was done at LSM engineering. LSM have
a machine that is capable of spinning 8 mm rivets.
Lashed up grinding method
One
remaining job was to grind the vulcanised rubber on the rear tyres.
I had previously ground the front tyres a couple of years ago. I lashed
up my old valve facing grinder as used for the front wheels. A small
geared motor was used to rotate the rear wheel. The gearbox had a
pulley and a very long drive belt from a combine harvester. Good having
Farming friends. I started the grind, very slow and tedious indeed.
In fact I had such a large amount of rubber to remove it was going
to take ages. If you try and apply too large a cut the rubber gets
hot, then melts in to a sticky mess. It is hard to get out of this
situation when this happens!
Turning the wheel rubber with the Webster & Bennett
boring machine
Allen
& Tom Prout called over, Allen suggested we turn the excess rubber
off and groove the tyres using his large Webster & Bennett boring
machine. The wheels were loaded in to Allen's van and taken to his
engineering works. The wheel looks small on the boring machine even
the O/D is 44 inches!
Hacksaw
blade tool holder
That
evening I made up a special tool holder that would hold a 1/2"
hacksaw blade that was heated, bent, ground to profile and tempered.
The excess rubber was simply removed using this method. The two grooves
were also added using this tool. Cutting the grooves was like parting
off a 44 inch rubber blank. the groove could be cut in minutes. The
tool was mounted on a small compound slide. The slide was attached
to a plate that mounted it in the Webster. I can supply details of
how this cutter works on request if anyone would like it.
Rear Wheel before after grooving & Grinding
The
edges of the rubber tyres were square after grinding. Radii were ground
on the rubber to reproduce the effect of original tyres.
Boiler lagging steel with wood visible on rear section
The boiler is lagged with 12 mm x 12
mm wood. I had to cut the wood to size using a band saw to get the
correct thickness. The strips of wood were cut to length and attached
to the boiler with Silicone sealer. This works quite well. The boiler
lagging steel was rolled from 1 mm mild steel sheet. Lots of accuracy
is required to fit the lagging steel. One wrong cut and all is wasted!
2 off M3 pan heads at centre joint of lagging sheets
The lagging sheets were attached to the
boiler at the top with 3 mm pan head screws. These fasteners will
be filled to replicate the effect of rivets. The 3 mm fastener were
threaded in to small pieces of 1/2" x 1/2" mild steel that
had been previously welded to the top of the boiler. This would allow
me to fix the sheets to the boiler and attach the boiler bands easily.
Boiler band and angle bracket
The boiler bands were guillotine cut
from 1/16" brass sheet. The edges of the bands were draw filed
to remove the sheared edges. This would be beneficial if I used the
band edge as a guide for lining! The boiler bands needed angled brackets
that would allow me to fit a fastener that would pull the two ends
together. I fabricated these from 1/8" brass. The brass sections
were silver soldered together. Quite a lot of filling and fettling
was needed to make the brackets nice.
Paint &
Colour scheme? Well this could be one of the
hardest part's of the build so far. I had trouble finding anyone who
could tell me what green to use. This type of engine was produced
for the War Ministry and would have been originally painted in plain
un-lined drab olive green. I think this would not look too nice. Boadicia
is nicely painted I am told the the paint was mixed and is not to
a repeatable colour code. So there are the standard Mc Laren colours.
Red Wheels , black boiler, tender tanks etc? One of our friends has
a young son called Joseph Lowen-Grey or J-Lo as I call him, Jo is
a BIG fan of steam and said he would like a green engine, Jo got his
wish!
I took some colour photo's to a paint
shop in Gloucester to try and get the correct colour. I bought 2.5
litres of RAL6002, looked alright in the shop? I had convinced myself
that it would darken with use! Later that day, Allen and Tom Prout
called over with Richard Hunter to view the progress. Ransoms green
was the conclusion! I had chosen a nice shade of Ransoms green. This
would look stupid on the engine. I returned the pain to Gloucester
to get the colour adjusted. Blue and black was added in large quantity's
to reduce the colour. I thought it would be fine after the change.
Allen called over later in the week and could see my frustration with
the paint. When Allen was leaving he Hijacked the paint and some photo's,
he knew I would use the paint on the engine later that week.
Well I must say that the following morning
Allen had a local car repair shop mix a lovely colour, looked just
like the photo's. At last I could apply paint and be sure the colour
was good. The metal was lightly sanded with 400 grade wet and dry
paper, degreased by wiping over with white spirit several times then
finished off with a cellulose thinner wipe. Two good coats of Hi-build
primer were sprayed on to the front wheels, belly tank and boiler
lagging sheets. The following day these surfaces were lightly sanded
and flattened with wet & dry sand paper. Later I applied three
coats of two pack paint. This gives a very durable finish that is
easy to clean and maintain, it will still be shining in ten years
or more. Dave Prout's Burrell Shownmans engine Nancy was painted in
two pack paint and still looks like new 14 years later. I name this
paint, Allen Prout Green! In fact it has paint code of 1942.
Boiler lagging sheets & belly tank
Partially
Lined front wheels
It
is hard to determine colour with photo's, look at the difference of
the front wheels and belly tank photo's. Obviously the camera flash
is changing the image.
To
apply the lining I have two types of tool. One is a professional BUEGLAR
lining roller set. The other is a home made item that was made from
an old draughting pen (placed on top of the roller set. Using these
tools is easy BUT, it takes practice. You need to do a lot of practicing
before you get the confidence to start applying lines to your single
coloured parts. I usually find that the last parts you do have the
best quality and you would like to start all over again!
Black painted Cylinder block, trunk guide support
& wayshaft
The
cylinder block assembly and trunk guide assembly was masked to allow
me to spray it as an assembly. The inner surfaces of the trunk guides,
valve spindles, Piston rod spindles and glands were all carefully
taped up with tape. Stove enamel was applied in several thin coats
by allowing the previous application to dry slightly first. This allow
you to get a really thick of paint!
The
Pre-painted lagging was re-fitted to the boiler, the boiler bands
were attached loosely. Care was taken to measure their spacing to
get them lined up and square. The brass bands were later used by the
paint application roller as a guide to apply the lined bands. Note
the paint that pulled off with the masking tape. Always a blasted
curse!
Crank and flywheel during drying after painting, Coal
Tub in the back ground!
Winch Drum Assembly
Painting
the winch drum was an easy task. Just hoist it up, spray it black
and let it dry!
Lots of work later!
The engine was run for it's firs steaming
on May 5th. 5 hours of fun and anxiety were had, getting the engine
out from the back yard, driving such a large and powerfully beast
for the first time, taking care not to flatten the children that were
all eager to get on for a ride. It is hard to put in to words what
this is like. I found the Mc Laren was very able to produce steam.
I feel that I had too much fire in the box, and with out the ash pan
damper door fitted it would reach safety valve blowing off pressure
in a very short space of time.
Boiler Steam
Test details to be added later!
