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Old 09-09-2005, 08:34 PM
Dan Fernandez
Join Date: Jan 2005
Location: Monterey CA
Posts: 188
WVO-Banjo bolt-fuel injector all in one

I just converted my '84 300 SD (204 K) to run on grease. It didn't like its first taste. It vibrates and then stalls once the veg. oil gets to the engine... Switching it back to diesel, it ran fine. I suspect its the injector nozzles, which are probably the originals and I doubt have ever been cleaned. May be the source of my mediocre mileage (about 20 mpg). I'll look into cleaning them (and will take any advice/input on that topic), but upon looking onto the engine I noticed fuel leaking from the furthest injector nozzle down (the one furthest from the firewall). The leak is from the return line, which seems to have popped off.

Here's my other question: Since I replaced the banjo bolt with a solid bolt for the WVO conversion, the other end of the fuel line is at least partially blocked by the solid banjo bolt. Could pressure buildup from the fuel in the line resulted in its popping off? It popped off the other end from the banjo bolt, so it is very suspicious. If so, maybe I should go back to my original hollow banjo bolt?

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Old 09-10-2005, 05:26 PM
coachgeo's Avatar
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Join Date: Jan 2003
Location: TX between Dallas and OK
Posts: 1,793
Do you have a fuel return loop? If so does this return loop include the injector return. If so remove the injector return from the loop and send it back to the tank(s). Keep the IP return looped when on veg fuel. This should reduce the back pressure on the injecor return system and not pop the return lines or the block off cap when your on veg.

After all the reading I have done my theory is to do it like this:

keep the hollow banjo bolt and the injector return system like OEM. More on what to do with IP return port on the banjo fitting in a minute. Use Pollak valve to select which tank this return goes for diesel and veg.

Now take your IP return and run this thru a pollak valve. On diesel use the valve to send it to its OEM port on the banjo body you dealt with above. On Veg. have the valve arranged to send into a loop that "T"s in before your lift pump.

Your veg. filter.... either use the OEM for both veg. and diesel or if seperate have the veg oil go first thru your veg filter and then thru the diesel filter. YEP both filters. This is more veg. to flush out when switching back to diesel butttt..... it keeps the OEM air bleed system intact. BTW the OEM fuel filter is very warm since it sits right at the engine.

overall I think this can be done with one six port pollak valve, but Im not sure I have not sat down and counted switches.

IMHO This keeps things simular to OEM when it comes to bleeding air from the system even when on Veg. It keeps the whole fuel system the same as OEM when on diesel.

IFFFFFFFF...... you want different fuel filter for the veg. you might consider getting one of a junk MB 617 motor. Yep the same arrangement. Then you can do a near complete two sided OEM system for air bleeding etc. Just block off the IP return port on the banjo atop the veg MB filter since this wont be used when on Veg. fuel.

Has anyone done either of these.
"If anyone knows other lessons I need to learn, please tell me. I'm tired of learning them the hard way".
by JerryBro

The Glow Plug Wait: This waiting period is a moment of silence to pay honor to Rudolph Diesel. The longer you own your diesel the more honor you will give him". by SD Blue

My normal daily life; either SNAFUed- Situation Normal... All Fouled Up, or FUBARed- Fouled Up Beyond All Repair

62 UNIMOG Camper w/617 Turbo, 85 300SD daily driver- both powered by blended UCO fuels

Last edited by coachgeo; 09-10-2005 at 05:32 PM.
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Old 09-10-2005, 07:52 PM
JamesStein's Avatar
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Join Date: Apr 2004
Location: Tallahassee, FL
Posts: 586
I thought about the solid banjo bolt and major modifications like that but in the end I opted for a return to the trunk line.

I've got a Racor 5 micron filter in the trunk. Vegi goes through this filter into a 6 port valve under the hood. The original diesel lines also go into the valve. Fuel supply and fuel return on the value connect to the hoses that originally went to the stock diesel lines. No modifications to the banjo, filter, lift pump, etc. There is a little mixing of diesel and oil in both the main tank and the vegi tank, but its minimal and I don't really see it as a problem and I've been running like this for over a year now.

So far I've had no problems other than clogging secondary filters more frequently than I'd like. I do not have a fuel pump in the trunk, the stock lift pump does the job just fine.

Is the original incarnation of my '83 300D. I've made some minor modifications (Replaced braided pvc hose with copper tubing. Added 2 more copper lines for coolant (HOH heating). Added a cage to hold 2 jugs of oil in the trunk) but the valve and return are the same.

The beauty of it is that even though I introduce a little air when changing the filters and changing jugs I never have bled the system other than to prime the lines in the first place.
'84 300CD Turbo 132k (Anthracite Grey) - WVO - My daily driver - Recently named coo-coo-coupe by my daughter.
'84 300D Turbo 240k (Anthracite Grey) - Garage Queen
'83 300D Turbo 220k (Orient Red) - WVO - Wifes daily driver

I'm not a certified mechanic, but I did stay at a HolidayInn Express last night.
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