Well, now that the excitement of steaming this
baby up for the first time is over, it's time to look at what needed to
be done next. Still have a ton of things to do like fixing a few things
that need attention to make it run a bit better. Also have to do the
lights, front pilot, skyline casing, skirting, install the
injectors, whistle, install the bell, on and on and on...
One of the problems I had was with
the flame being sucked out when opening up the throttle when going up a
grade. If this was a coal burner, this would have been great as it
would pull a lot of air over the coals and get the fire real hot. For
propane, that's another thing. A club member (Jason) suggested I
enlarge the blast nozzle because he could hear that the engine was being
choked on the exhaust side. This would also lessen the affect of the
flame being sucked out when the throttle is opened up. The picture
below shows the original blast nozzle on the left. It had a 3/8"
diameter hole and made it like a venturi. I also got carried away and
used a cross pattern. The second time it was steamed up, the nozzle in
the center was used. It has a 1/2" diameter hole and is also shaped
like a venturi. This improved the situation but still had excessive
exhaust back pressure and the flame still was being sucked out (but not
as often). The nozzle on the right was drilled out to 5/8" diameter and
also shaped like a venturi but less radical. This is the one I stuck
After a couple test runs, I raised the blast nozzle to the bottom of the
petticoat to reduce the vacuum in the smokebox. This totally goes
against the 1:3 and 1:6 “cone” theory which may be great for coal but
useless for propane. After these changes were made (and other
Fuel System Mods),
flame-outs were more rare.
Another problem I had to fix was
the electric blower. The blower I got was too powerful and sucked so
much air through the flues that it made it near impossible to light the
fire. The original plan was to use a door dampener (as can be seen in
the picture). The idea was to open or close this door to regulate the
air. It kind of worked but once it got hot, you couldn't touch it.
That problem could have been fixed but it didn't allow for fine tuning
of the air flow. A light dimmer was installed on the blower which fixed
Once the blower problem was fixed,
I still had to figure out why the burners had a small weak flame. The
engine steamed up well but still wasn't up to it's potential. The flame
was yellow at the tips and were being starved of fuel or air (or both).
When I tested the burners on the bench, all the flames were strong and
blue. Something happened once they were put into the firebox. Another
club member (Carl) suggested that the propane quick disconnect between
the tender and the engine might be starving the burners of fuel. After
the quick disconnect was removed, the engine was taken outside for a
static test. The propane tank was connected and the modified blower was
put on the stack. Then I lit her up. The blower speed was increased
until the flames were a perfect blue. As you can see from the picture
below, the flames look great. Another problem solved.
Further changes were made in the
Fuel System Mods section.
The last thing on my list to fix
before the next steam-up was the front truck. It derailed twice the
last time I took her out. The truck tried to turn totally sideways but
the cylinder caught it along with my "expensive" SuperScale cylinder
cocks. Bent the cylinder cock on the right ride and put some nice cuts
in the cylinder cover. I didn't want this to happen again. I had to
find out what caused the derailment but before I did, A chain was put on
the front truck to limit the movement so it can't hit the cylinder
again. The prototype actually has this also (and I thought it was just
for looks in this scale).
I finally figured out why the
pilot truck derailed for no apparent reason. The drawbar had no play
for vertical movement, just horizontal. When the engine went up, so did
the tender and vice-versa. As the tender bounced up and down, it would
push the engine up and down also, causing the front truck to derail when
it lifted (or something like that). I made the drawbar tight, thinking
that it was good to reduce the "play" when starting/stopping. I made
the holes a bit larger and to allow more vertical movement without
making it "sloppy", both holes on both sides we beveled. Problem fixed!