wvo heating, flow, and air in line problems

[Robster Craw]

Help anybody!
I am working on getting my 1981 240D to run on WVO. It runs fine on it for a few minutes, but after a while I get power loss. Looking at the inline filter I see that there are bubbles popping up. When I disconnect fuel line it is not always full of oil, it has much air in it. I am having a heck of a time finding out where this air might be coming from. When I switch back to regular diesel the bubbles go away. My theories so far:

1. Stock filter is clogged...though I have changed it twice with no effect (possibly wvo not hot enough?)
2. Leak in wvo supply line...though I have rebuilt the whole thing twice, pressurized all lines with air and sprayed soapy water on fittings to look for leaks, and pressurized all lines with water looking for drips...couldn't find any)
3. Improper priming of the lines leaves a fuel bubble trapped in the line somewhere (I loop the return line in wvo mode, in diesel mode return line goes to diesel tank)
4. Fuel pump cannot lift the wvo because it is still too thick...though I have it up to at least 130F when it leaves the fuel line and I keep reading about people who use svo unheated without this problem.

I have also tried a booster pump to help push/pull wvo through the system, but it seemed to only increase the rate of bubbles pouring into the line.

I would also appreciate any ideas anyone might have about heating the oil. Unless my temperature gauge is broken, I seem to only be able to get the oil to 130F tops, though the wvo is heated in the tank, passes through a heated fuel filter, a heated hose, a stanadyne fuel heater (300w) that I have rigged to be on all the time, and a glow plug right before the stock inline fuel filter.

Thanks very much for any suggestions you might have.

[TwitchKitty]

Hi, welcome to the forum.

http://biodiesel.infopop.cc/eve/ubb.x?a=frm&&f=159605551

Do you know about this forum? Have you read the FAQs over there and the routing and plumbing diagrams? Do you understand how the stock system traps air?

When you used the electric pump did you try it back at the outlet from the tank?

There is a faq here about veg oil also. The search should turn up many questions like this also.

[Robster Craw]

Thanks for the reply.

I have been using the pump after the vegoil filter (a heated racor 1000fg) because the filter says it should be installed on the vacuum side of the pump.

The air leak was where the glow plug screws into a 1/2" adaptor for my fuel line! It would not leak until it hits a certain temperature, then it would leak! I tightened the heck out of it and it seems to have solved the problem. The glow plug has very small threads and when it got good and hot I could see oil starting to leak/smoke out of the threads. Because it only happened after the plug got to a certain temp. it was a pain to find.
I have read everything I can find about heating the oil. It seems lots of people are using glow plugs, and getting temps up to 200F, so I can't figure out why my oil is still not hot enough...130F seems to be the top end no matter what. I thought that the air leak was responsible but now that I have fixed that I still have the problem. I daren't add any more electrical heaters to my maxed-out electrical system. I want to get that stuff HOT FAST!

[rwthomas1]

What are you using to get WVO temp? Is it possible there is a problem with the gauge/sender? This should be easy to test. Remove sender and immerse in boiling or near boiling water. Maybe the gauge is stuck? RT

[TwitchKitty]

Are you using a temperature switch for the glow plug? What switch?

Is the Stanadyne a diesel fuel heater? It maybe made for cold weather and not to heat like you are looking for.

I would think that 130°F is pretty good for temp. Mine runs without any heater. I have thought about it and planned it but have never needed it. I think I might save on filters if I had a heater.

I love this thread. Where else on earth would a conversation take place between a character named RobsterCraw and a character named TwitchKitty?

[estod]

Two suggestions: go to Greasecar.com & read the archives .... and go to Frybrid.com (where the more active posters from Greasecar went) and read their archives. Twitch may have a good point about the Stanadyne -- the electric unit most people use is a VegTherm (biofuels.ca). Many people mention that the heated filters they try don't add that much. I am planning to use a heat exchanger + a veg therm, but don't expect to heat the tank as I am in a warm place already. A lot has been written about the need to heat VO to avoid coking, said to eat up engines. A guy who used to post on Greasecar frequently - moniker OneTank - eventually said that he and several friends all destroyed their engines by using unheated VO (after spending quite some time giving people guff for bothering to heat theirs).
A gentleman named Dana Linscott has plans for sale, as well as parts on vegoilconversions.netfirm.com. He posts on Greasecar and Frybrid, seems very knowledgeable. The moderator & posters on Frybrid could no doubt give you excellent trouble-shooting advice ...... much like the many kind souls (SMART kind souls) do on this site ....
Best of luck

Ed

[veg_burner]

estod, i went to greasecar & frybrid looking for onetank's posts, searched under 'onetank' but nothing came up. i was curious to hear of his experience.

[Jimmy Joe]

I recommend a boost guage in a veg system. Great for troubleshooting, and giving a heads-up when filter cloggage is occuring. Boost is nice for both vacuum and pressure apps, so you can switch it around in various configuartions.

Can anyone explain to me how in the world a single-tank system does not have cold oil splashing into a cold motor on startup?
(cold oil combustion might mean coking, no?)

[jake1090]

From What I have read... A successful install of a one-tank-system involves a smaller tank 2-3 gallons to start and stop on diesel. I can't advocate starting and stopping on oil because of the obvious coking issues. As far as heating the oil... I run engine coolant lines to the tank and I also have my fuel filter wrapped with coolant lines...it keeps the temp right around 160 degrees...and my car has been running great... the last 4000 miles have been on WVO less the startup and shutdown intervals. I drive 100 miles everyday...so the savings has been really nice.

[Whiskeydan]

What happens if you place diesel in the wvo tank? Bubbles?

I'd say its easier to suck air than the thich wvo. Look for leaks before the lift pump.

FYI, I run a one tank system on my cummins. Up to 80% wvo/diesel blend with no heat. Ambient temp here is around 65-75f. Any cooler, I just put more diesel in. 50/50 down to 40f.
OK so far 10K miles. Idles REAL slow 'till it warms up though.

[TwitchKitty]

http://www.vegburner.co.uk/suitability.htm

This site discusses why some engines are more prone to coking. It has references to many research projects.

In a nutshell, the combustion chamber must be designed to keep the oil away from the cylinder walls.

[Jimmy Joe]

Originally Posted by jake1090

From What I have read... A successful install of a one-tank-system involves a smaller tank 2-3 gallons to start and stop on diesel.

Hmmmm. That sounds strikingly similiar to two-tank.

[mespe]

1) Remove tank cap and see if it'll run longer. (Sounds like no air is replacing the oil as the oil is burned)

2) Ensure that all heaters continue to operate while car running

3) Add a little diesel to the tank and see if it still stalls (try 10% diesel 90% oil, then increase to 20% diesel until the car continues to run)

4) any pictures??? they would help 1000%

Good luck,


http://www.benzbonz.biz

Marty

[stayalert]

Originally Posted by Jimmy Joe

Hmmmm. That sounds strikingly similiar to two-tank.

LOL....perhaps a 1 1/5th tank system? I'm working on getting my 300D to "baseline shape" and then I hope to delve into 2 tank WVO world....