Want to convert car to run on veg oil

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Want to convert car to run on veg oil - anyone done it ?
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boff

Joined: 23 Mar 2005
Posts: 354
Location: Still alive and kicking

Posted: Wed Jan 23, 08 10:48 am Post subject: Want to convert car to run on veg oil - anyone done it ?
We want to convert our diesel car to run on veg oil, seen lots of sites promising all sorts. Wondered if anyone had done it already, found any snags or useful tips etc ?

VSS

Joined: 14 Jan 2007
Posts: 2845
Location: Llyn Peninsula, North Wales

Posted: Wed Jan 23, 08 10:55 am Post subject:

I daresay that someone will give you the technical lowdown.

BUT,

we ran a Diahatsu 4 Trak on 90% veg oil with no problems except that it was difficult to start.

I beleive this can be overcome by installing a second, small tank. You put diesel in the little tank and use that to start off, and once the engine is warm, you switch over to the veg oil.

Performance wise, the engine ran very smoothly on the oil, and the torque at lower revs, particularly when towing a heavy load was better than on diesel.

I say ran because it is now off the road - nothing to do with the fuel though - knackered transfer rods in the gearbox.

boff

Joined: 23 Mar 2005
Posts: 354
Location: Still alive and kicking

Posted: Wed Jan 23, 08 11:26 am Post subject:
Thanks VSS, I thought it was possible just to "chuck it in". As for the starting issues thing, I'm sure Ive seen that mentioned somewhere before. I assume (uh oh....) that its something to do with the viscosity of the oil. Come on techno downsizers, where are you ?

Penny Outskirts

Joined: 18 Sep 2005
Posts: 23385
Location: Planet, not on the....

Posted: Wed Jan 23, 08 11:56 am Post subject:
It does smell like chips cooking though Our old truck ran on it without any problems, I think it's flash new jobbies you have viscosity problems with, but I'm really no expert

tahir

Joined: 28 Oct 2004
Posts: 45426
Location: Essex

Posted: Wed Jan 23, 08 11:59 am Post subject:
Maxwell Smart, where are you? (He runs his motor on it)

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Wed Jan 23, 08 11:59 am Post subject:

Since Veg Oil is physically rather different to what cars are designed to run on, whether or not this is a good idea at all depends greatly on the car.
Or specifically its fuel injection system.
That cannot be converted.

Conversion "kits" are firstly to overcome the starting problem.

There are generally three functions.
1 - a changeover switch between diesel and veg. So you can start it on diesel as easily as usual, and change to veg once the engine is warmed up. BUT its up to you to remember to change back *before* you shut down the engine, so it has diesel in the system, ready for the next start.
2 - a second tank and low pressure supply pump for the other fuel (probably small tank for diesel)
3 - a means of preheating the veg oil before it gets supplied to the diesel injectors by the (bloody expensive) high pressure pump. Warming it makes the veg less viscous, so the load on the pump is closer to what it was designed for, and helps the veg to spray better from the injector so that it combusts more efficiently, keeping the smoke and particulate emmissions almost as low as with with proper diesel fuel - but biodiesel combusts even better, with still lower particulates.
Yes the "chip shop" smell is unburned Veg Oil in the exhausts *plus* a load of particulates -- indicating that the injection spray isn't vapourising the oil completely, so it isn't combusting completely.

Some tractor-like old diesels (notably old Mercs) will apparently run on "chucked in" veg relatively happily, at least in summer. But starting in even a mild English winter isn't going to be easy.
And "high tech" (high efficiency) diesels are going to be *more* (not less) sensitive to their fuel.
Most of the difference between high and lowish tech diesels is in the sophistication of their injection systems.

Conversion kits don't convert the actual *engine* at all.
They are fuel supply conversions.
And these engines were not designed to run on veg oil.

There are widespread internet myths about Herr Diesel "inventing his engine to run on Veg Oil".
These are bollox.
Diesel's first ever independently verified performance figures (Professor Schroter, Augsburg, 1897) were running on fossil petroleum fuel.

He did indeed demo engines running on Veg Oil.
And milk powder.
And coal dust.
Amongst other things.
Don't hear much about them these days.

All those engines were way too massive to fit into vehicles.
They all required a compressed air supply.

I mentioned the high pressure injection pump above.
This was only invented 20 years after Diesel's death.
The injection pump enabled "diesel" engines to be used in vehicles.
About 30 years after the engine was demo'd on Veg Oil.
And coal dust.

The problems with Veg Oil are not particularly in the engine - the combustion bit. Though the combustion isn't as complete, so its less efficient...
The potentially expensive problems are with the injection system.
Invented 20 years after Diesel's death.
And NO WAY designed for veg oil...

Ever seen the stickiness that builds up on a chip pan?
Those gums will be in the injection system if you run Veg Oil.
How well it copes, depends on how that injection system design was engineered by its manufacturer.
And has sod all to do with Rudolf Diesel's exhibition demonstrations 100 years ago.

MarkS

Joined: 01 Aug 2006
Posts: 2626

Posted: Wed Jan 23, 08 12:24 pm Post subject:
What Dougal says. plus the fuel pumps are an issue. diesel fuel pumps are designed to use the diesel as a lubricant. The more modern the pump the finer the tollerance and the more likely you are to have a very large bill as a consequence. What engine is it? tbh on any modern vehicle the saving is minimal and the risks high. I'd sooner look at low dose acetone or whatever.

kevin.vinke

Joined: 19 Dec 2006
Posts: 1304
Location: Niedersachsen, Germany

Posted: Wed Jan 23, 08 12:37 pm Post subject:
All of the above. Generaly you can´t use it with the newer injection system (rail type). Veg oil works well with the Merc m600 series engines in summer, for all year round you need to install a system which switches from diesel to SVO after the engine and the fuel preheater have warmed up. It very much depends on your fuel pump. The bosch works fine Lucas will die very quickly even with the kit.

Mary-Jane

Joined: 13 Jan 2005
Posts: 18397
Location: The Fishing Strumpet is from Ceredigion in West Wales

Posted: Wed Jan 23, 08 12:52 pm Post subject:
I think Gervase runs our Land Rover on 33% (or thereabouts) veg oil.

Behemoth

Joined: 01 Dec 2004
Posts: 19023
Location: Leeds

Posted: Wed Jan 23, 08 12:55 pm Post subject:
There's a thread on the River Cottage site about this at the moment with some links amongst other stuff.

Treacodactyl
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Wed Jan 23, 08 1:03 pm Post subject:

Mary-Jane wrote:

I think Gervase runs our Land Rover on 33% (or thereabouts) veg oil.

Funny you should mention that... I've been thinking about getting an old diesel Landie to renovate and it would seem logical to consider modifying it to use veg oil if the engine is going to be worked on. Does anyone know if a 300 or 200TDi could run on veg oil or would something earlier be required?

Which brings me to another question, I understand some engines are more suitable to run on veg oil but does anyone know of some reliable advice? Some sites seem far too optimistic.

Behemoth

Joined: 01 Dec 2004
Posts: 19023
Location: Leeds

Posted: Wed Jan 23, 08 1:06 pm Post subject:
RObbed from River Cottage, no idea if they are useful: https://www.vegetableoildiesel.co.uk/fuelsdatabase/database/az_list.php?alphabet=l https://www.landyworld.co.uk/vegoil.htm https://www.veggedup.com/category/vegetable-oil-conversion/page/2/

wellington womble

Joined: 08 Nov 2004
Posts: 15051
Location: East Midlands

Posted: Wed Jan 23, 08 6:00 pm Post subject:
We just chuck veg oil into the surf - about 50:50 in the winter, and 100 percent in the summer. The newfangled injectors are so fine, they clogged up, I understand. Also, Mr Womble tells me the fule pumps on defenders tend to persih if you put veg oil in them, but I don't know where he got the info from. I'll ask him later.

Gervase

Joined: 17 Nov 2004
Posts: 8655

Posted: Wed Jan 23, 08 6:08 pm Post subject:

Lucas fuel pumps don't like veg oil, but Bosch ones don't mind, so the TDi engine should be fine. When I use it, I keep the veg oil content to about 20 per cent, so that the pump still gets lubricated and the mix doesn't get too viscous in cold weather. And that's with a Lucas pump, which doesn't seem to have had any trouble after two years of Tesco value rape-seed oil (but even that has doubled in price since the summer to around 78p a litre, Grr.).

boff

Joined: 23 Mar 2005
Posts: 354
Location: Still alive and kicking

Posted: Thu Jan 24, 08 11:00 am Post subject:
[quote="MarkS"]What engine is it?quote] Well spoted MarkS, might have been useful to include that: Its a three cylinder merc turbo diesel (direct injection, not common rail) in a Mitsubishi Colt. not sure on the pump, I'll have a look.....

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