Q:Where to place a fuel cut-off valve?

[FlameRed]

Hello again folks. Another newbie question here. Possibly something I am concerned about for no reason, but I will ask anyway since is the first diesel engine I have owned.

I understand it is possible, but not likely, that the 6.2 NA can run away under some unlikely conditions. So I am thinking of putting a manual fuel shutoff valve somewhere, possibly on the hose that goes into the fuel filter since it is easy to get to in that event?

I guess this can also serve as a rudimentary anti-theft device too.

So my questions are:

• Am I just paranoid, and a runaway is so unlikely this is totally unnecessary?
• What is the ID size of the fuel line going into the fuel filter?
• I am guessing I could just use a brass valve from the hardware store for this purpose? Anyone have a link to what they used and maybe a picture of it installed? Or is some other specialty type valve necessary?

Thanks in advance!

 

[Mogman]

Just carry a pair of pliers, in the EXTREMELY unlikely event that the engine starts to run away pinch off the return line from the IP and that will kill the engine.
If the engine truly ran away it would likely hand-grenade before it would run out of fuel with a cutoff valve anyway so just run.....
I have heard of engines that would not shut off (pinch the return line) and the possibility the engine could run away if the top cover on the IP was not installed correctly but I have never heard of an engine just running away on its own (with this type of IP) I have personally have had a Detroit 2 stroke run away, that is why they put a trap door on the air intake. (thank God)
So IMHO yes you are being overly paranoid.

 

[REF]

As mogman said, When you hear of Detroits running away They are talking about the old 2 stroke Detroit engines (453 / 671) and they had a trap door that when tripped slammed over the intake of the blower to shut them down. trust me when say it takes a brave person to reach over and trip the shutdown when the engine is running away.

 

[Mogman]

As mogman said, When you hear of Detroits running away They are talking about the old 2 stroke Detroit engines (453 / 671) and they had a trap door that when tripped slammed over the intake of the blower to shut them down. trust me when say it takes a brave person to reach over and trip the shutdown when the engine is running away.

The two stroke Detroits have cam driven injectors and a rack, when you shut the motor down and then return the shutdown control to run the rack goes to wide open.
When you start a Detroit the rack is in WOT until the engine reaches whatever the throttle position is set (usually idle) that is when the governor pulls the rack back.
Problem is after sitting for several months the rack can get stuck in WOT so when you go to start it it sounds like an F1 engine going down the straight away.
I had this happen on a 4-53 in my Oliver 1900 tractor but the trap door control had long ago been removed from the operator position so I had to get off the tractor and reach into the blower and trip the door as it was screaming bloody murder, now that will get your adrenaline flowing!
It actually did not shut the air off enough to kill it but it slowed down to about idle belching TONS of black smoke as it was still dumping WOT fuel into the cylinders, I then cut the fuel valve off and waited until it starved for fuel.
Both of my Oliver's with Detroits have working trap door controls now!!!
I was actually on the 1900 this morning, moved it out to replace a bad bearing on the PTO output shaft.

 

[Mogman]

As mogman said, When you hear of Detroits running away They are talking about the old 2 stroke Detroit engines (453 / 671) and they had a trap door that when tripped slammed over the intake of the blower to shut them down. trust me when say it takes a brave person to reach over and trip the shutdown when the engine is running away.

REF, did you get my PM?

 

[REF]

sorry I missed it but just replied to your PM.

 

[Hummermark]

The two stroke Detroits have cam driven injectors and a rack, when you shut the motor down and then return the shutdown control to run the rack goes to wide open.
When you start a Detroit the rack is in WOT until the engine reaches whatever the throttle position is set (usually idle) that is when the governor pulls the rack back.
Problem is after sitting for several months the rack can get stuck in WOT so when you go to start it it sounds like an F1 engine going down the straight away.
I had this happen on a 4-53 in my Oliver 1900 tractor but the trap door control had long ago been removed from the operator position so I had to get off the tractor and reach into the blower and trip the door as it was screaming bloody murder, now that will get your adrenaline flowing!
It actually did not shut the air off enough to kill it but it slowed down to about idle belching TONS of black smoke as it was still dumping WOT fuel into the cylinders, I then cut the fuel valve off and waited until it starved for fuel.
Both of my Oliver's with Detroits have working trap door controls now!!!
I was actually on the 1900 this morning, moved it out to replace a bad bearing on the PTO output shaft.

Hi not all 6-71 governors go to wot when stoped and left the ones on the 6046 twin pack stay in the no fuel rack position.

 

[Retiredwarhorses]

Hello again folks. Another newbie question here. Possibly something I am concerned about for no reason, but I will ask anyway since is the first diesel engine I have owned.

I understand it is possible, but not likely, that the 6.2 NA can run away under some unlikely conditions. So I am thinking of putting a manual fuel shutoff valve somewhere, possibly on the hose that goes into the fuel filter since it is easy to get to in that event?

I guess this can also serve as a rudimentary anti-theft device too.

So my questions are:

• Am I just paranoid, and a runaway is so unlikely this is totally unnecessary?
• What is the ID size of the fuel line going into the fuel filter?
• I am guessing I could just use a brass valve from the hardware store for this purpose? Anyone have a link to what they used and maybe a picture of it installed? Or is some other specialty type valve necessary?

Thanks in advance!

your paranoia will destroy ya…this is a non-issue.

 

[87cr250r]

Detroits with a hydraulic governor go to the no fuel position when there is no oil pressure (engine not running).

The older Detroit Diesel engines had a fixed fuel rack that contributed to the runaways. When an injector fails and gets stuck, that cylinder stops firing but the stuck injector also blocks the fuel rack from moving. When you remove the load from the engine, it can't reduce power on the running cylinders and that starts the overspeed. An air damper on the blower inlet shuts shuts the engine down during the overspeed. You can remove the shutdown damper if you install the newer style rack which has springs that allow the other cylinders to return to the no fuel position.

Another engine notorious for runaways is the Cummins Pressure-Timed system. If you block the return line fuel pressure increases outside of the governor's control and the engine will overspeed.

Your DB2 pump on your 6.2/6.5 isn't prone to these conditions. The pump also holds a large volume of fuel so it will run for quite some time even after the supply is cut off.