|
Williams Brothers 1/8 Wright J-5 "Whirlwind" engine - Part 4 by Rogério ´Rato´ Marczak As I said in part 3,
the kit has no sort of fixture to install the engine on its mount.
During a CAP mission in a watch repair shop I found a good alternative:
tiny metal nuts and bolts. They are chrome plated (too bright),
so they will be painted over with flat clear. In addition, they
are too short to pass all the way through the engine mount section
and mount structure holes. My plan is to glue the engine on the
mount using regular cement and place these mini-bolts capping the
holes as a decorative measure.  The metal nuts & bolts used. But before installing
the bolts, I attached the #1 cylinder. Wow, now we´re talking
about engines.
Next I installed the nuts/bolts around the engine mount arc. They were brushed with flat clear and washed afterwards. I then proceeded with the remaining cylinders, always checking the alignment. It may seem stupid to mention it here, but the cylinders have no alignment pin or slots to ensure a proper fit. To make things a bit worse here, the cylinders rest very loosely on the bases. Antecipating problems with the pushrods, I shortened the cylinder bases by sanding each one of them on a glass mounted piece of rough sandpaper.
The pushrods were the
next parts to be installed in place. After waiting the cylinders
glue to dry, I discovered that all the pushrods were too short to
fit between the pushrod pads and the bottom of the rocker boxes.
Even after sanding the cylinder bases every pushrod remained about
0.5 mm too short. To solve the problem, I punched plastic discs
and cemented them at the end of each pushrod. Of course I had to
retouch the area with gloss black paint. The fit was much better
then, and I installed the right pushrod of each cylinder first,
then the left ones.
 Lengthening the pushrods.
At this point I discovered
that, for some reason I still don´t understand, a wedge shaped
gap remained at the pushrod attachment point of each left rocker
box. They were quite visible for some cylinders, but putty was out
of question. I then mixed carpenters (wood) glue with gloss black
Gunze acrylics (H2) and carefully filled each gap using a fine pointed
brush. In some places a second application was needed. The excess
was removed with a moistened cotton swab. Because carpenters glue
shrink much less than regular white glues (and dries faster, too),
it is virtually impossible to say where was filled.
And so I finished with
the pushrods. Not a smooth assembly, sure. I think the kit lacked
a bit of engineering here...
The next step was the installation of the intake pipes. They fit nicely to their flanges, so I placed a small pool of cement in each flange and installed the pipes. The other end (the one which enters the distribution housing) was simply inserted in their holes.
I must confess that the
idea of differential application of flat and gloss black on the
intake pipes (see
part 1) really gave a nice touch here. It was an enjoyable
project so far... at each new part installed, it looked a bit more
like an engine.
Before going on, I had
to stop and take care of a few smaller details. Firstly, I needed
eighteen new spark plug pipes. I selected three pipes cut from the
kit rubber parts (the only reasonably in shape) and prepared the
silicon molds. After a half dozen resin pouring sections, I got
my 18 new resin pipes. They were cleaned and drilled at both ends
to fit the spark plugs and the new ignition wires.
Another thing I had
to take care of was the advance link rods. I broke one of them during
their removal from the sprues. The kit parts are not bad, but I
lost the broken end and decided to make a new pair of them. Using
the kit part as a guide a length of brass rod was cut, and small
sections of brass tubing were telecoped at the ends. The spherical
hinge at the ends were made by a novel method (to me, at least):
small balls of solder. Just melt solder wire on a rubber pad by
holding the solder point over the melted wire for some seconds.
I had to make quite a few of them only to select the four with roughly
the same diameter. They were then superglued at the ends of the
rods. The joints were smoothed with a coat of Mr.Surfacer, and the
excess wiped out with isopropyl alcohol.
Then I proceeded to
the new ignition wires. I started with cooper wire. Bad idea. While
a single wire is easily bendable, when you group three or four of
them is another story, and I thought it would be impossible to conform
a sheaf of them in the tight space behind the magnetos. Then the
cooper wires were replaced by telephone wire. Much better: more
easily bendable and the thickness seems to be more correct than
the original bubber part. In addition, I guess it would be impossible
to clean all the seam lines in the rubber item.
The wires you are seeing
in the photos are not the only ones. They are the ones which will
be inserted in the distributor blocks of the magnetos. The other
wires will connect the spark plugs to the harness loom, and so they
can be installed later. I used the kit part as a guide to cut the
all the wires and painted them with flat brown to simulate that
rusty look. Here´s another hint: these wires will be bent
to their positions after painting, so enamel paint is not a good
choice (you may run the risk of chipping/breaking the paint coat
after all the work). I elected polycarbonate paints - very similar
to the usual acrylic paints, but with a different formulation. These
paints can be found in art stores, and they remain slightly flexible
for many days after drying. And then the harness
loom was glued to the crankcase. I´m afraid of the next step:
to bend all these wires without damaging the painted parts or breaking
the fragile loom mounts.
Let´s see how it
goes in the next part. Now, where the hell I placed those magnetos? |
