This is a short add-on to my earlier post - can you stop the monster.
It pursues, basically, two purposes - one - to present yet another
amusing example of how unstoppable the mechanically injected diesel
engines can be, and two - to provide a proof to the universal fact that
in absolutely any situation, despite all training, planning and preparation, something at some point will go wrong!
About a month ago I got involved in restoration of
an outdated Toro 500 - a heavy underground front loader, powered by a
true engineering miracle - a V-twelve Deutz diesel. These air cooled
engines, equipped with mechanically governed injection system
(and I am referring to all versions, not only to the V-twelve), have
earned the fame of being bulletproof survival experts, capable of
putting out countless work hours under all sorts of abuses and
environmental ill-treatments. I was told at the mine that due to the
newest environmental restrictions they weren't allowed to buy such
machines any more, but were still allowed to run the already existing
ones. This particular loader had been stationary for about two years
before a decision was made to "resurrect it" as an auxiliary piece of
equipment. Since for the last year the machine had served as a spare
parts warehouse for its alike brothers, it was "partially missing" when
the works started, and after the reassembly the hydraulic brakes
wouldn't work - which was the main reason I was called to assist.
The malfunction turned out to be bad connections. Luckily,
the hydraulic schematics was there, and the the problem was quickly
solved. While making the necessary adjustments and verifying the rest
of the hydraulic system, I had to turn the engine on and off several
times. Since I had already had my share of, let's say, peculiar
experiences with unstoppable diesels, one of the first things I checked
was the engine shut down system, which was working flawlessly, and was
activated by a small spring pre-loaded hydraulic cylinder. To stop the
engine a valve injected oil into the cylinder, and the cylinder would
pull or push on something, and the engine would stop. I am not sure
whether it was a decompressor or a fuel valve, but it doesn't matter
really.
Everything was working fine, the engine was starting and
stopping whenever required, and my job was almost finished. As I was
talking to the shop mechanic, I pointed out a pilot line oil filter,
which apparently had never been replaced as nobody knew it was there.
The all helping fellow immediately took out the filter element and
rushed to the warehouse to get a replacement. The filter cap,
naturally, remained unscrewed... Very pleased with myself (the job had
gone incredibly well...) I deiced to make but one last pressure check,
and "the funny part began..."
Just like I'd been doing it for the last couple of hours,
I installed a pressure gauge, went to the cabin, and turned the
ignition key... By the moment the key had gone around half of the
travel a lightning fast thought flashed thorough my mind - an open
filter in the pilot line means no pilot pressure, you moron!!! How the
hell are you going to stop the engine?!! - by that time my brain gave
the fingers a command to stop turning the key, but it was already too
late - the tenth of a second the ignition contacts touched each
other was enough for the stupid but very well adjusted diesel engine to
start turning... By instinct I pushed the stop button (what a fool!)
already knowing that there would be no pilot pressure to operate the
stopping mechanism (which, by the way, was well hidden in the middle of
the engine). I climbed the three meter high machine in under a second,
and saw exactly what I was expecting to see - the engine going
pa-pa-pa-pa, and the stream of hydraulic oil coming out of the
dismounted pressure filter and poring all over the loader and onto the
shop floor...
The hours were late, and since the shop mechanic ran to
the warehouse I was alone with the mindless critter, which was poring gallons of
hydraulic oil on the floor. Calling for help was not an option since I
couldn't possibly outscream the twelve jugs, so I had to find a way to
stop it, and stop it fast (but not for good...) I looked around me, and
saw a piece of rubber band on the floor, which seemed to be large
enough to cover the intake, so I went for it and spread the band
directly over the huge air inlet - I could swear it was air tight, but
the f#cking engine wouldn't stop!!! I was looking at it and wasn't
believing my eyes! How in hell was it possible?!!! The diesel was
clearly choking, spitting out clouds of black and white smoke from the
exhaust, but it was not stopping!!!
In another desperate attempt I managed to twist the fuel hose in my
hand, and after half a minute of doing
ta-pum-pum-ta-pum-chaka-chaka the starved bustard finally seized
kicking. When I cooled down and descended the loader, doing all my best
to avoid landing in the oil pool on the floor, I finally looked at the
engine with a "seeing" eye and noticed that the V-twelve had two air
intakes - one for each six cylinders - so to smother it I had to close both of the inlets... which I didn't.
To conclude this - once again, mechanically injected
diesel engines can be a pickle to stop once they've started turning, so
before putting one in service, make sure the shut down system works and
that you have studied other stopping options. Oh yes, one more thing -
in case you consider smothering an engine, don' t forget that it can
have more than one air intake!!!
