meratz

If a diesel car or truck can run on well filtered fry oil, why go through the trouble of converting it to biodiesel? The chemicals used to convert the oil are nasty and it is something I do not want to deal with. From what I have read you can have a small tank of straight dieasel in your trunk for starting up and heating the fry oil. You then turn a valve which stops the flow of diesel and starts the flow of the fry oil. You then do the opposite when it is time to stop the engine to clear the engine of the oil so it doesn't solidify and clog your engine. This seems to make a lot of sense to me and keeps me free of chemicals more toxic than the original deisel I am trying to get away from or at least use less of. What am I missing?

Hero999

For the reasons you stated above, additives are required to stop it from clogging the engine when it cools.

It's also possible that other ingrediants are added to help lubricate and protect the engine.

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Nigel Goodwin

Have you ever heard of TVO? (Tractor Vapourising Oil), pre-diesel that's what tractors used to run on (a VERY cheap paraffin) - start up on petrol, then switch over when warm. We used to run an old Ford Popular pickup in the fields in the same way as kids, we fitted two motorbike tanks in the back, one petrol one TVO - mostly because we could pinch TVO from the farmers storage tank, and it cost hardly anything.

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ericgibbs

hi,
I saw a farming program recently, where the guy had converted his truck to run on cooking oil.
To get over the 'cold' start problem he bought an 'off the shelf' 12v heater coil, for the fuel line.
At ready to start up, he set the heater for about 20-30 secs, started OK every time.

Sceadwian

The emissions are going to be absolutly horendous.

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mneary

In moderate climates, it's not hard to start a Diesel. When the temperature or atmospheric pressure drops it's another matter.

I had a VW Rabbit Diesel that never did start when I was at abut 12,000 ft and 15 degrees F. Fortunately I wanted to go downhill. It finally started at about 2,000 ft.

Preheating the oil sounds like a good idea if there's adequate battery capacity. Remember you may already be drawing 60A or so for glow plugs and 50-100A for the starter.

Emissions from biodiesel are ok if you really like fried food.

Sceadwian

Yeah, I bet atmospheric pressure can be hard on diesels. Throws the compression ratio right out the window.

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Oznog

I read up on this awhile ago, it's well described on the 'net.

IIRC not only is SVO (Straight Vegetable Oil as opposed to Biodiesel) difficult to start on, it can leave varnish deposits while cold. Also the SVO needs to be flushed on shutdown- I can't recall if that's because the engine varnishes as it cools down or because the fuel lines will contain SVO running right up to the engine so even if you try to switch the fuel system to normal diesel to get it started there's still SVO in the last part of the lines.

Preheating the lines ensures the SVO will flow in the cold, but it won't get the engine itself up to temp so varnish problems would still be there. Also if you have it gelled in the injector, heating up the line won't thin it there until the SVO starts flowing but it won't start flowing because the gel has clogged it. So ideally you'd need to heat the injector, line, even the bottom of the fuel tank to totally avoid the problem. In the real world, I imagine people still make it work with less than ideal heating systems though.

Also SVO can be of less than consistent quality, such as varying in PH. Some oils can be harmful to the engine. The biodiesel process can adjust for such things.

Biodiesel- or even SVO, IIRC- is actually pretty decent on emissions. OK won't compete with a Prius, but it's supposed to be pretty good.

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Hero999

Don't some vegitable oils absorb small amounts of water that could cause corrosion? Isn't that the reason why the engine needs to be flushed before it's shutdown?

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Oznog

Well I've already said more than I know for sure.
You're on the internet, why not research SVO and biodiesel info from the experts?
http://journeytoforever.org/biodiesel_make.html#2svo

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kchriste

There was a guy here in town that used an unmodified Ford 150 pickup truck this way. It had dual tanks so all he had to do was put regular diesel oil in one tank and deep fryer oil in the other and remember to switch between them at the right moments.

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Hero999

Is there a way to to this legally?

I don't fancy getting caught and having to pay a hefty fine.

I also have a feeling that it won't work on modern turbo diesel engines.

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Nigel Goodwin

Not in the UK, it's seriously illegal - the government don't like you defrauding them of excise duty - also bear in mind excise officers aren't hampered by the rules and regulations governing the police, no search warrants required, they can just kick your door in and enter!!.

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Hero999

It wouldn't bother me if the government really taxed fuel just because it's bad for the enviroment, if that were the case then biodiesel would be tax-free but it isn't.

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Souper man

"The emissions are going to be absolutly horendous"

Ive seen many programs that use fry oil, and they say it smells just like french fries!