OK, I have a question that I couldn't find an answer to on this forum, though maybe it is out there somewhere. I just converted my 84 300 SD to run on vegetable oil and I went the kit route. I am still working on the oil sources, but the car conversion is done. One thing that doesn't make sense to me, though, is the fact that I replaced the hollow banjo bolt that seems to connect 3 lines and the fuel filter ( a 4-way intersection) with a solid bolt that seems to isolate all 4 so that there is no connection a all between them. My buddy with an '84 300 D had run his car on WVO without the banjo bolt replaced and he almost overran his WVO tank with backfilled diesel. Upon replacing his banjo bolt with the solid bolt he ran fine and the backfilling stopped.

So, at the moment I am running from my diesel tank but with the banjo bolt replaced with the solid bolt. I am all ready for filtered WVO. My question is: what was the purpose of the hollow banjo bolt, since I seem to be running fine without it?

Thanks.

two banjo bolts sit ontop the fuel filter one on top and one slightly
to the side... there is a fuel loop there.... and you put is a new tank
and hoses and electronic switch and your switch probably has on half
for wvo and the other for diesel.... so you eliminated the need for the banjo bolt...

now your diesel probably circulates through this electric switch rather than through this banjo bolt....

Blueranger,

I think you are right, but I'll look at the setup again. It doesn't seem that complicated, but I clearly don't yet understand all that's going on. There still seem to be some 'dead ends' on the new replacement banjo bolt, but I'll think about it some more.

Thanks for the explanation - you are correct that there is some circulation happening with the valve switch setup.

The OVERFLOW banjo "bolt" ontop of the fuel filter has a small passage in it that acts as an air bleed valve. Any air that makes it into the fuel filter below it is attracted upward by several factors and exits out thru this little passage. This bled out mix combines inside the banjo "body" with the the extra fuel not used by the IP (IP overflow/return line) and the extra fuel not injected via the injectors (injector overflow/return line) These two are fed into the banjo "body" via two ports. In OEM arrangement all this; via a thrid port, is sent back to the tank thru the cigar hose and on into the return line to the tank.

A solid banjo "bolt" does NOT block all fuel if you keep the banjo "body" there. In that case it ONLY blocks what bleeds up thru the filter. All the other things flow right around the banjo "bolt" inside the banjo "body" and out to the tank.

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__________________
"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

Thanks, Coachgeo. So, since there is still flow around the solid bolt, the only thing that replacement of the hollow banjo bolt with the solid one does is block the flow of air up from the fuel filter and impede somewhat the flow of fluid?

If I hadn't converted my car and added a second tank and valves for the WVO, could I still have replaced the hollow banjo bolt with the solid one and still run OK?

Yep but I highly doubt it impedes the flow in a manner of consequence.

Yes and No. The Lift Pump that is in the engine area "sucks" fuel from a fuel tank a good distance away and this vacuum makes it easier for air to get sucked in via hose attachements, bubbles etc. Without the air bleed of the banjo bolt air will occasionaly enter the IP. An IP is made to compress diesel not air and its suppose to inject diesel into the engine and not air. Air in the IP makes the engine run poorly or not at all if there is enough air entering the system.

There are several options for creating some kind of air bleed action going on.

__________________
"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