Detroit Diesel 3-53 would not stop after air intake closed? WTF?

    I would guess that with the valve cover off, the engine is breathing
through the "breather" hose on the valve cover?
    Normally the breather would be applying vacuum to the valve area &
crankcase and only "breathing" the limited amount of blowby from past the
rings... but with the valve cover off it's "breathing" fresh air?

David Courtney wrote:

That sounds plausible. Also wondering why he isn't using a fuel shutoff
to shutdown like every diesel I've operated uses.

Great idea. Thanks.

I have added a fuel shutoff just 5 minutes ago. It helps in getting
the situation under control.  

On Tue, 21 Jun 2011 13:04:26 -0500, Ignoramus31413


Didn't the engine have a spring loaded "damper" in the intake when you
got it?

yes, it does.

Ignoramus3171 wrote in
rec.crafts.metalworking  on Wed, 22 Jun 2011 07:11:36 -0500:


FYI: A CO2 fire extinguisher can stop a runaway engine.
A little pricey, but sometimes things can go real bad, real fast.
If you have one, you might want to have it handy.

--

Dan H.
northshore MA.

On Wed, 22 Jun 2011 07:11:36 -0500, Ignoramus3171


That is the normal emergency shutdown device. But as someone wrote it
is a bad practice to use them as a "normal" shutdown device. If you
have some strange wiring around the engine and a solenoid on the inlet
damper you probably have the remnants of an automatic shut down
system. They usually have sensors for high water temperature, low oil
pressure and over RPM.

wrote:


The GMC engines are two stroke and use a roots blower to provide
scavenging pressure. As the blowers are lubricated by engine oil
pressure if a shaft seal fails it injects lube under normal operating
pressure into the incoming air stream. If you shut off the fuel under
this condition the engine won't stop; if you shut off the air it will.

On 06/21/2011 12:37 PM, Pete C. wrote:


Many Detroit Diesels from that period had an emergency shutdown that
moved little arms into the path of the valve spring retainers, jamming
  one valve per cylinder partly open , and in so doing, killing the
compression.  That may be what Iggy was referring to as something moving
in the valve cover area.  Taking off the valve cover on those
engines definitely would defeat that mechanism.

Jon

wrote:


I believe that the spring loaded rack system was made as a substitute
for the inlet damper which DD recommended be disconnected. However
engines used in the oil industry are still required to have inlet air
damper type shutdowns.
Cheers,

John B.

I have both the rack and air damper.

The cause of my trouble was that one injector was stuck and the rack
could not pull the arms out of the injectors.

i

On Wed, 29 Jun 2011 21:19:19 -0500, Ignoramus20088


Nope Iggie, you had an old Jimmy. You rack was the old style that
could stay partially open if an injector stuck. Later versions called
a single screw" will shot off all the injectors except the one that
sticks
Cheers,

John B.

wrote:


A lot of errors - hmmm must be my spelling checker. It should have
read "called for a "single screw" will shut off".

Cheers,

John B.

On 06/21/2011 09:20 AM, Ignoramus31413 wrote:

Either you have a leak in your intake manifold, or leaky intake valves,
or it's sucking air past the rings from the crank case.  Or I have my
head up my ass -- I'm no diesel mechanic, nor a truck driver.

I thought diesel engines were supposed to cut off fuel to stop, and only
cut off the air as an emergency stopping measure?

I was told, a long time ago by someone who wasn't a diesel mechanic (but
did drive them quite a bit, and pay for them when they broke) that a
diesel can 'run away' by sucking both air and crankcase oil past the
rings, and be unstoppable until it has seriously depleted the
lubricating oil.

I:

1: don't know how often that happened.
2: don't know if it's true at all (but it was my dad, who didn't
    usually exaggerate, and who was in a position to know)
3: don't know if it's common now, as opposed to the mid 1970's
    when I heard it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

Tim Wescott wrote:


I owned a Volkswagan Rabbit diesel for a
little while.  The rings were worn and after
a few weeks about an inch of crankcase oil
would build up in the air box.  Hitting a
bump or going around a tight curve would
slosh the oil into the intakes and give you
a very exciting 5 seconds of about 150%
full throttle.  Especially if you were in
that tight turn at the time.

I learned to pop the airbox open and mop
out the oil about once a month.

Maybe I have my head up my ass too.


I have added a fuel cutoff valve.


I thought that it was all about just sucking oil, not air. That is a
very scary possibility.

i

Ignoramus31413 wrote:

A chap I used to know, now dead, told me lots of interesting stories
from when he worked in construction and some of those included large
earth moving machinery where the diesel engines ran away. In one case
the operator realised what was happening and drove the machine into the
tunnel wall to stall it before any serious problems occurred. Those big
machines in question had oil bath air filters IIRC and in some cases the
engine would start to run on the oil in those. The chap had an
interesting life, he said on another occasion he was almost killed by
shrapnel from a generator donkey engine exploding when someone  used
compressed oxygen to start the genset rather than compressed air, that
was when he was working on the Aswan dam.

wrote:


A drilling rig? No compound?

wrote:


http://www.energmart.com/a,12,Drilling-rig-National-T45 -(800hp)-Drawworks,-127%E2%80%99.htm
for the inventory of a small (800 HP) rig.

The compound connects the main engines to the rest of the rig, and
allows the use of several engines to power the rig.