Author Topic: Fuel Shutoff (Read 12836 times)

jsw123 · « **on:** December 02, 2009, 12:04:29 PM »

I am wondering if a standard fuel shut off will shut down a 24/2 engine without a serious delay time from when the solinoid shuts off and the engine does. I wonder because it is said that these engines have a very high idle efficiency and that means it may take a while to drain the remainder fuel in the line. Is it necessary to have an actuator on the lever for the governor to shut off the injectors instead?

Tijean · « **Reply #1 on:** December 02, 2009, 01:37:23 PM »

They dont shut down quick enough to satisfy any emergency condition and subject the injection pump to dry running. If the fuel shut off is ahead of the filter you also pull a shit disturbing vacuum on the filter. When you go ro restart you will likely have to do some bleeding. Shutting the fuel rack is the way to go with possibly a positive shut off on the air intake. The intake shut off is not really a dead positive way either as valve overlap can allow enough air in to still allow engine to shudder along.

toydiesel01 · « **Reply #2 on:** December 02, 2009, 06:49:21 PM »

I'm not sure of the pressure on the lister's injector but alot of the old diesel's injection pressure was 2300 to 2800 pounds. Something to think about if you are thinking of shut off's in the injector line.

Tijean · « **Reply #3 on:** December 02, 2009, 08:23:45 PM »

Injector crack pressure of 2300 or so PSI is the only escape route for the injector pumps positive displacement so you definitely cannot put a shut off valve in the high pressure discharge line or you will be picking up broken pieces off the floor or out of the crankcase.

somian · « **Reply #4 on:** December 04, 2009, 10:14:13 AM »

In principle you could put a dump valve off the injector line, so that it is closed for normal running, and open to stop the engine. However actually doing so without disturbing the stiffness of the injection system would be another matter completely, and of course for a 24/2 you would need two of them. The way to stop a diesel is push the rack to the "no delivery" position, or do as Petter do on AV1s and such like, to stop the pump travel. This last cannnot easily be done on a Lister CS.

Ian

listeroil · « **Reply #5 on:** December 04, 2009, 04:47:25 PM »

No question about it close the fuel pump rack the way it is designed to stop. The pump is designed to cut the fuel completely when in the off position. Switching off the fuel supply to or from the pump is not the way to stop these engines. The only reason to switch off the fuel from the tank is when changing filters so your fuel don't leak out, absolutely no other reason to switch off your fuel supply.

Lister's made a very nice shut off system for the Start O Matics and other generators using this type of engines. That uses a strong solenoid pulling against a strong spring for the engine to run. The when the power to the solenoid is cut the spring pushes the rack to the no delivery position on the fuel pump, and inserts the decompressor ready for the next start. here's some pics.

Above is a drawing of the solenoid coil that fits in the casing. Ive got an empty casing and used this drawing to get a quote to have a new one made I was quoted 300 pounds to get one wound. I didn't go there, they would be quite easy to wind up yourself and they don't need to be a brass tube up the middle plastic will do. Early ones had a brass tube later ones made a bit cheaper used plastic tube. If anyone wants more information and size's I can do. As i got one in bits at the moment.
Mick

Stan · « **Reply #6 on:** December 05, 2009, 06:50:26 PM »

300 pounds to get a solenoid wound? That's cause for an investigation into fraud charges!

Stan

Doug · « **Reply #7 on:** December 05, 2009, 07:41:15 PM »

Maybe its a 300 pound man spininng the coils Stan...
Sitting at a winding bench all day is not good for your figuere

Stan · « **Reply #8 on:** December 05, 2009, 07:58:33 PM »

Climbing up and down a 24' extension ladder all day IS good for your figure. I had to buy an new 5000 box of crown staples a month ago after going through that many stapling up 1/6 T&G sofitt and cedar shingles for a month. Lost almost 25 lbs! My wife calls me a wraith.
Stan

Doug · « **Reply #9 on:** December 06, 2009, 12:30:47 AM »

So now we know how you keep that swelt figuere.

Just don't fall off the roof

jsw123 · « **Reply #10 on:** December 06, 2009, 02:54:35 AM »

Thanks Listeroil,

The arm that the solenoid is attached to is also the arm that moves to allow more fuel to the engine when the mechanical governor calls for it , correct? If so, how does it move with the arm and also shut the engine off?

jsw123 · « **Reply #11 on:** December 06, 2009, 10:12:52 PM »

is there anyone who has tried using two solenoid valves on the suction side of the injector before on a 24/2?

listeroil · « **Reply #12 on:** December 07, 2009, 12:50:08 AM »

jsw123

The picture shows the engine in stop position with the valve lifter engaged and the fuel pump switched off.
When the solenoid is energised it pushes up a rod in the middle of the solenoid which pulls back the valve lifter and at the same time twists the arm back out of the way to allow the governor to open the pump up to max.

More on the coil winding it needs less than 2 kilos of 0.9mm enameled copper wire to wind one of these cost £36.46 inc delivery.

Mick

jsw123 · « **Reply #13 on:** December 07, 2009, 01:03:40 AM »

I think this will not work on a 24/2 because the place where the solenoid would connect to is the place where a rod goes that connects the governors from both sides. It may be necessary to have the solenoid on the shut off handle instead.

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