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Timmeeh 07-23-2015 02:18 AM

OM617 wvo conversion
Hey all. I have a 300GD om617 that I've installed a second tank for wvo on. Have some questions about the plumbing.....

Everyone is talking about plugging the banjo on top of the diesel filter. I did not (yet?). I'll try to explain how i plumbed this:

Diesel tank->prefilter->primary diesel filter->feed valve->lift pump->IP!
VO tank->veg filter->feed valve->lift pump->IP!

So for the return I've tee'd Injector overflow and return from IP to common return valve. Plugged the Injector overflow hose on dieselfilter banjo.
Diesel: Return valve->banjo on dieselfilter->cigar hose to diesel tank.
veg: return valve->tee'd before veg filter (loop).

After some trouble i managed to bleed air from diesel side and started.

1: Will the lift pump suck diesel through the return line since the filter is under vacuum instead of pressure, and will this fuel bypass the filter? Or is the fuel returned to this banjo bolt going through the filter again?

2: Would it be a better solution to buy a 3rd valve, and get both filters after lift pump, so that they can be under pressure instead of vacuum?

I have also thought about getting an electric pump for the veg side, but I'd prefer to use the stock lift pump. Maybe to bleed air on veg side but not only this..

Hope you understand, unfortunately I cant make a diagram as I'm on my work computer.

Timmeeh. Libula libulla!

Timmeeh 07-24-2015 02:19 AM

Could i just fit a one way valve on the cigar hose, problem solved? It will return fuel, but not suck fuel (or air when the tank level is low)?

Also I'm trying without a heat exchanger first. Partly because the 617 engine eats everything, but mainly because it is limited space under the hood. And doesn't the eckes filter (VW oil cooler) heat the oil enough on it's way out?

oldsinner111 07-25-2015 11:05 AM

I quess with cheap diesel no one will talk.I couldn't afford electronic valves,I used all manual valves.The only thing I bought was injection line heaters,a electric thermostat to turn off heaters at 180 degrees,A used heat exchanger,fuel hose,fm 100 5 micron filter from napa.I used a boat tank. I used a common water hose splitter,with 5/16 fittings,to either send veg or diesel to engine,oh yeah a 10 psi electric pump to push both fuels.At engine area.My 5 micron filter head has two inputs,and two output.I blocked one output off.Fuel would go into heatexchanger into primary filter into FM,then to engine lift pump.At the cigar return hose I used a gas valvave reducded to 5/16,and a tee before valve to shut return line off,then recycled hot fuel back into FM100 input opening.When in veg mode return fuel was recycled.Hot coolant to heat exchanger also had manual valve to turn off hot coolant.

Timmeeh 07-25-2015 11:41 PM

Don't know where diesel is cheap, but in Norway it's the same as before the oil price dropped.... so veg we go!

I think i'm gonna buy a one way valve just to be sure. Cause i had trouble bleeding air at first. Low level on diesel tank made it suck air from the return line... Or is it better to replace bolt with a solid one?

I also have ball valves on the coolant. So if i'm going on short trips, or don't have wvo I can just close them and don't run coolant through the veg system. Made an alu pipe coil with the fuel pickup in the middle of it. Have a 40L alu tank made for racecars!! in the trunk, running every hose inside the car to maintain heat :cool: Winter gets cold...

oldsinner111 07-26-2015 06:08 AM

I never understood the bolt theory,thats why I looped my fuel back to system,for one it keeps hot fuel at the motor,two if you send hot fuel back to the veggie tank,it will cause trouble with water.I never had problems with air because I added a electric pump.It bleeds air in seconds.Diesel has dropped here in U.S. to $2.50 a gallon.WVO is so hard to get,I just keep 150 gals. of used clean,motor oil,for emergency fuel.

Timmeeh 07-26-2015 01:49 PM

I think the problem is that if you don't plug the banjo, and run the return hose (where the cigar hose is) to the return valve; You will get some veg rests in the diesel filter. Because the returned fuel is passing the diesel filter... And when you place the filter before the lift pump it will become under vacuum and therefore suck fuel from the return line.

Atleast I had trouble bleeding air with low level on the tank. And from what I heard the return line is about 1/4 fromt he bottom. I managed to bleed air when i filled 20L diesel on the tank so it became about half full.

hehe thats about 1/3 of the price I pay in norway!!! And wvo is not that common here, so free flow on the oil!

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