what makes a detroit run away?

[steponmebbbboom]

some clarifications; on a two-cylinder detroit with one injector rack seized in the wideopen position, a sprung rack wont really help with shutting down the engine as you're only cutting power to half the engine. also, a detroit engine cannot run away in reverse, the timing is so far off you will barely get an idle out of it. which is why blocking the intake might actually stop it successfully. and thirdly, pulling the stop lever does not cut off fuel flow to the injectors, injectors are fed from a gear pump that supplies fuel to a common rail and jumper lines to the injectors, and pressure is maintained at 50psi through a restrictive orifice in the return elbow coming off the head.
detroits can overspeed for a number of reasons, stuck injector racks being one, plugged airbox drains being another, improperly set or damaged governors most commonly, and leaking blower shaft seals. if you have the means to stop an overspeeding engine with a large CO2 extinguisher, it is the least harmful method as closing the emergency stop flapper or plugging the intake will create enough vacuum to suck the seals out of the blower shaft. be aware the engine moves a lot of air at those RPMs and you do not want to get body parts stuck in the intake when this happens.
if you have a small CO2 extinguisher either deadhead the hydraulics slam it into top gear and dump the clutch or close the flapper before the RPMs pick up again. you have only seconds to save the engine before the block and crank are destroyed.
if you have a machine with a detroit take this opportunity to verify that you have an emergency stop flapper installed on the blower intake, that can be easily tripped from the operator's position so that safe control of the machine can be quickly regained in the event of a runaway. and make sure the operator is drilled and drilled again on its proper use so it's not forgotten in a panic situation. D

 

[steponmebbbboom]

also do NOT discharge a dry chemical extinguisher of any size into the intake of an engine unless you want to destroy it.

 

[Phil]

Good post, welcome to the forum Steponme:drinkup
I've noticed whenever the name Detroit Diesel comes up, in any forum, the response is a good one. I worked on one once in a Dynahoe backhoe, a 3-71, as I recall. There is an interest in putting these engines in pick-ups, including the 3-53 Gamma-goat engine that had the aluminum block. I don't believe there was a more adaptable series of engines ever made. Phil

 

[Koehringman]

Detroit

Yeah, Those classic screamin' Detroits. I love em' Got a 4-71 in my Koehring.

 

[steponmebbbboom]

i am actually looking for a 3-53T for a jeep project i'm building but id prefer not to use the aluminum gamma goat engine because of the FWhsg pattern no PTO plates and the corrosion problems of an aluminum block. thanks for the welcome. D

 

[tripper_174]

Keep us posted on the jeep project step...should be very interesting!

 

[steponmebbbboom]

im not the first one to do it,
YouTube - wheelin' thru a wash #10
ronnie passmore's jeep has a 3-53NA with T19 trans and dana 300 case, 14 rear and 60 front with 44" swampers. i came up with the idea on my own and met up with him later, i like detroits and would like to run it on SVO on the street rather than build it for serious offroad like he has. D

 

[Komatsu 150]

I would just like to mention another way Detroits would run away in the real old days. A machine with an oil bath air cleaner would try to go up or down a steep grade and oil from an over full air air cleaner would slop over and get sucked into the engine. The air cleaner usually had too much oil not from being over filled when servicing but because someone was too lazy to clean it and the dirt built up in the bottom and raised the oil level.

 

[chuck jacobs]

detroits will run away .as i said ,i almost stalled my dragline,it started running in reverse wide open.the cable drums turning backwards also,causing a rats nest in the cable.i dont know how to explain it any other way.

 

[mitch504]

We rebuilt a 6-71 and instead of the steel plate we usually kept at hand, my brother set a piece of 3/4 marine plywood on the radiator. When we started it for the first time it ran away, he grabbed the piece of plywood and dropped it on the intake. That old girl sucked the middle out of the plywood and ate it without slowing down. We had to scramble around to find a piece of steel and by that time we had to pull the engine back down and start over.

 

[Mikefromcny]

Think thats a screwed up looking block? Look up a Volkswagon VR6.

 

[atgreene]

I've never had a Detroit run away on me, yet. Couldn't you grab a fuel filter and either unscrew it or shut off the fuel/crack a fuel intake to shut it down? Unless of course it's getting oil from elsewhere.

I've had a few 3208's run in reverse, weird feeling to see exhaust pour from the intakes.

 

[powerjoke]

I've actually seen a diesel engine consume its own oil and blow itself up, so it's not always fuel related.

Pj

 

[monkey]

wow, great reads :notworthy

I have a back up generator with a 6-71 in it, ya'll got me scared to walkin the contianer when it's running

 

[Komatsu 150]

Well it's not that it happened a lot it's just when it did it was really memorable.

 

[stinkycat]

Detroit's overspeeding

In the mid 60's we were testing Donaldson air cleaners on electro haul trucks with 12V149 Detroit Diesels with 4 turbos and 2 roots. the engine was under full load and the Donaldson Tech was blocking off the air inlet and slipped and covered the inlet completely the turbos over sped and the roots blowers rotors were sucked into the valley the engine started to take off the shut down. Both blowers were junk all 4 turbo over sped and were reduced to junk. That was a wild time.

 

[Cat Wrench]

what makes a detroit run away?

An approaching Cat will make a Detroit run away in shame!

I got the privilege to see a detroit over speed and have a major mechanical "malfunction" that created a new exit port for oil in the side of the block at a shop I was working in. I believe it was a 8V-92. I will never forget that sound. It had a very high pitch at the end. It seemed like the noise stopped for a couple of moments before I heard the loud boom, kind of like a pause, it was really cool.

 

[upbrakie]

I've been around alot of Detroit's but haven't had the priviledge to see one overspeed yet. We have 3 operable machines and 2 that aren't with 3-53's, one with a 2-53 and one with a 4-71. They have been fairly reliable engines with few problems but fnding parts for them is becoming more and more difficult.

Andfor starting engines backwards, I don't know how I did it, but I managed to fire the diesel in an old pony start cat D47U backwards. Oil started pouring out the air breather. Luckily, I was able to open the compression release seconds after it fired to kill it. Since then, the engine has run like a top!

 

[Zed]

The older 2 stroke detroits had an injector rack that was adjusted by 2 screws, and as said way back at the start of this post, if an injector seized then the whole lot stuck in that position, if it was in full fuel, then you had an engine overspeeding.
Because of this fault, they changed the rack to a single screw adjuster, and a spring system so if one injector stuck, then all the rest could return to a no fuel position.
If you have an older 2 stroke with the 2 screw rack, you can change it to the new style and avoid a catastophe.
Other ways to overspeed them are to have a nitwit do a tune up for you and not read the book. Or get same nitwit to do some repairs and put rack control rod in the wrong way, seen that happen, instant death of 16V92.
Also seen a 16V149 overspeed and had to shut it down myself, which scared the crap outa me hitting the blower emergency shutdown flaps with the poor thing screaming. That was a mechanical fault in yeild link and we got it going again after replacing all the heads. The valve train doesn't like high RPM and broke valve bridge posts off everywhere, but other than that it was ok.
Whenever we started an engine after major work we'd leave the intake off turbo and have the service manual right there to jam on the turbo.

Remember the golden rule "RTFB". Read The F**king Book.

 

[johnnypixon]

There is great wisdom in the words of steponmebbbboom. Today I fired up my hein-werner c12 hd excavator and the 4-53 detroit diesel suddenly flew into full throttle runaway. I had the knowledge to do the right thing (jump out of the cab, run through the mud to the other side of the machine, climb up on the swing platform over all the hoses etc. and hit the emergency shutoff) but it happened so fast-- I paniced, jumped out of the cab and I ran. That terrifying roar chased me into the woods. I hid behind a giant oak tree waiting for the inevitable BOOM. Then by the grace of god the old beast calmed down and began to pur like a kitten. I'm not sure if it's an injector or the govener but I'm sure that I won't start it again until I connect the emergency shutoff on the engine to a makeshift lever in the cab.