?? flow paths of the 617 fuel filter - PeachParts Mercedes-Benz Forum

coachgeo · #1 08-05-2003, 08:00 PM

can anyone describe or diagrahm the various flow paths of fuel into, out of and around etc. of the 617 fuel filtering arrangement .

Thanks in advance

George

#2 08-06-2003, 07:32 AM

You can look at it and trace it. The line from the tank goes into the prefilter. The lift pump then goes to the main filter, from the main filter to the IP. What might confuse you is the bypass hoses.

Good luck,

P.E.Haiges · #3 08-06-2003, 07:23 PM

coachgeo,

Larry didn't finish the bypass hose explanation.

The overflow lines from the IP and the injectors are connected to the top of the filter housing. Below that connection is a bleed hole to get any air out of the filter. Since the pressure inside the filter is higher than in the return lines, fuel does not go into the bleed hole but any air and a small amount of fuel come out. The excess fuel and any air is then routed back to the fuel tank thru the return fuel line

P E H.

coachgeo · #4 08-06-2003, 08:35 PM

Quote:

Originally posted by P.E.Haiges
coachgeo,

Larry didn't finish the bypass hose explanation.

The overflow lines from the IP and the injectors are connected to the top of the filter housing. Below that connection is a bleed hole to get any air out of the filter. Since the pressure inside the filter is higher than in the return lines, fuel does not go into the bleed hole but any air and a small amount of fuel come out. The excess fuel and any air is then routed back to the fuel tank thru the return fuel line

P E H.

Now this is KEY information for my purposes. THANK YOU>>>

Please allow me to claify what you are saying. Please correct me if I am wrong.

Path of return fuel (overflow) from the IP:

Unused fuel leaves the IP --->enters a union at top of filter---> air and small amount of fuel from inside the filter joins the IP's return fuel thru a little hole in top of the filter---> then both exit on to the tank.

What I'm hopping is that I can find a way to maximize the amount of warmed fuel (vegetable oil) going back to the IP, but still expell the air. Or does that happen already? I get the feeling right now that most goes on to the tank along with the air.

If most goes back to the tank could I do the following:??

1. Block off the return where it "enters" the top of the filter.
2. Leave intact the fuel return line where fuel and air "exits" the top of the filter and returns to the tank.
3. "T" into the fuel line from the tank (before the filter), the warm returning fuel from the IP, thus sending it (and any air)directly back into the filter.

NOW---> The air and a small amount of fuel will continue to (like normal) enter the the small hole in top of the filter and "exit" on to the tank. Majority of the fuel (now warm fuel) goes on to the IP and the injectors.

So overall the difference being is:

(a) Warmed fuel from the IP goes right back into the filter instead of returning to the tank
(b) The small amount of fuel and air that "exits" the top of the filter, no longer combines with the returning fuel that came from the IP. Now only this small amount and the air goes on back to the tank.

Will this flow path work? Warmer fuel is the goal thus reducing the viscosity of the Vege oil making it closer to that of diesel fuel.

THANK YOU....... Im gettng close to making this all happen.

Palangi · #5 08-06-2003, 09:45 PM

Coach

If I remember right, a while back you posted some links to various Unimog and MB engine manuals. Wasn't there a 617 manual in there? If so, there should be a clear diagram of the fuel flow in there.

coachgeo · #6 08-06-2003, 10:24 PM

Quote:

Originally posted by Palangi
Coach

If I remember right, a while back you posted some links to various Unimog and MB engine manuals. Wasn't there a 617 manual in there? If so, there should be a clear diagram of the fuel flow in there.

I do not "yet" have any manuels for the 617, thus my questions.

No Unimogs used the 617. The manuels I posted about were all USMC SEE Unimog. Also there is a cut away drawing of a few of the non mog engines but that is it. The cut away may be of interest to you non moggers. I'll post the link to those later.

P.E.Haiges · #7 08-07-2003, 01:46 AM

Coachgeo,

As far as I can tell, you have the fuel flow figured out correctly.

I understand what you are trying to do: Keep the warm SVO going into the IP and engine instead of sending it back to the fuel tank.

I will have to study your modification plan. Its too late tonight so I will try to answer tomorrow.

P E H

coachgeo · #8 08-07-2003, 03:14 AM

Quote:

Originally posted by P.E.Haiges
Coachgeo,

As far as I can tell, you have the fuel flow figured out correctly.

I understand what you are trying to do: Keep the warm SVO going into the IP and engine instead of sending it back to the fuel tank.

I will have to study your modification plan. Its too late tonight so I will try to answer tomorrow.

P E H

Tanks man.. mucho appreciato

P.E.Haiges · #9 08-07-2003, 09:47 AM

Coachgeo,

I think if you disconnect the IP and injectors overflow lines from the filter and tee them into the input to the fuel pump and leave the fuel return line to the tank from the air bleed hole you will keep the warm fuel near the engine and still return any air to the fuel tank.

The problem is starting when the engine is cold. You still might need a second tank for Diesel to use until the engine warns up enough to heat the SVO. If it gets cold the SVO may solidify in the fuel lines and tank and you won't go very far that way.

That is the problem commercially available kits attempt to solve. They run the engine on Diesel fuel until it is warm and pump the hot engine coolant to the furl tank to warm the SVO in the tank and lines so the engine can be run on SVO in cold weather.

P E H

coachgeo · #10 08-07-2003, 12:35 PM

Quote:

Originally posted by P.E.Haiges
Coachgeo,

I think if you disconnect the IP and injectors overflow lines from the filter and tee them into the input to the fuel pump and leave the fuel return line to the tank from the air bleed hole you will keep the warm fuel near the engine and still return any air to the fuel tank.

Coolio. I like MB

Quote:

The problem is starting when the engine is cold. You still might need a second tank for Diesel..., Kits are available....

......
P E H

I am well aware of the kits, coolant heat, 12v heat etc etc. BUT I still got much to learn. Also, I'm lookng into commericialization of my own version at some point. I am also looking into sovents that reduce the viscosity. Hopping to find one that is good for the engine and elimenates/reduces the need for heating. On this trip I will be cutting the Oil with gasoline (5-15%??) to reduce viscosity a little. Not sure the % cause the 617 motor is know to run on the worst of things just fine. Others cutting with gas are having glowing success even at start up (in warm climate) There is a new bioD manufacturing process I am keeping my eye on too.

On the Mog I have a total of 4 tanks. One will be diesel which I will drive on at start up and prior to stop most often, one Large one will be a filtering system that cleans old oil. The last two are tied together creating essentually a tank with a huge baffle in it. This is where the cleaned vege oil will be sent along with returning fuel. I will drive from this tank once warm, as it nears empty I pump out the Large tank into it. I then I refill the Large one with Vege and start filtering again. My car will run on vege too so I can pump out of the Large tank into my car as well.

Thanks again for the invaliable information!!!!!