Burning Vegatables. Running SVO/WVO in 2024

[Talbot]

I've been running a bit of Veg in various diesel cars/vans for a fair number of years, but have never done it quite as comprehensively as I do now.  It's very well known that a lot of IDI engines are very suitable for this, and I know a fair number of people on the forum either run Veg or have dabbled with it in the past.  I've tried describing my setup a few times, but never quite manage it properly.

The car:  Is the Merc E300 in my sig.  It's ideal for Veg for a great number of reasons and is the main reason I am now on my 3rd OM606 engine.  The reasons are:

• Combustion swirl chamber (IDI) is designed to operate on low Centane fuel, ensuring massive amounts of turbulence, along with a glowing ignition point that the atomised fuel has to pass by, meaning incomplete combustion is hugely reduced (Note, this is NOT the same as an XUD with it's ricardo pre-combusion chamber.. it's IMO a better arrangement for Veg)
• Bosch inline injection pump, which is lubricated with an oil feed from the engine, meaning it doesn't rely on the lubricity of the fuel.  These will pump grease if asked to.
• Higher-than-usual compression ratio of 22:1, which is high for a turbocharged diesel.  This creates higher adiabatic compression temperatures, leading to better ignition.
• Big, poweful and smooth.  Inline 6-cylinders, 3.0 litres and 130kw (on diesel) means this is not an underpowered vehicle.

I have not made any changes to the car other than swapping seals out for Viton when they start leaking.  I may do a twin-tank conversion in the future, but right now I'm focussing on the oil used.  Which in my case has been used oil.  There is a lot of things to consider with used oil, and I'm hoping I'm covering most of the issues.

New oil can, in most cases, be simply lobbed into the tank and run, either at 100% in summer, or thinned with diesel in winter, mainly for cold-starting.  Once the engine is running, you could use 100% without issue, but without a twin-tank conversion, you're forced to start the cold engine on whatever is in the only tank, so consideration has to be given to low temperature starting.

Used oil is a bit different, and you have to be aware of what it's been used for.  It has three main contaminants:  Water, sediment (solids) and sludge (grease)

Water has never been too much of an issue for the oil I've had.  After all, if the fryers have been running at their usual temperature of around 260c, all water will boil off to steam in normal service.  It's only really an issue if water has gotten into the oil while it's been cold.

Solids have to be removed.  What level you remove them to is important.  More below.

Sludge and grease is generally due to the oil having been used for cooking meats.  The animal fats come out of the meats being cooked and end up in the oil.  These are an issue, as they always have higher solidification temperatures than the vegetable oil.  Leave these in the oil, and you'll be back to the same cold-starting issues mentioned above.

How I do it:

The oil I have been getting recently (thanks to @Lacquer Peel, @juular and @MrsJuular in various ways for this) is really not bad oil at all.  However, it does have a fair bit of solids and animal fats in it, which I need to remove.  I go for a 5-stage filtration system, which thus far appears to be protecting the car quite well.

Step 1:  Coarse filtration.

I managed to get hold of a load of 125um stainless steel mesh from a company I used to work for a while back.  This can be bought online for not-as-much-as-I-expected, but this is what I have, so I thought I'd use it.  125um is open enough that clean oil blats through it fast enough, but it does catch a LOT.

This is a 25L barrel with the top cut off and some of the 125um mesh made into a place to pour the dirty oil straight into.  This comes in 20L "cubies" from various places, as it's what the oil came in new.  It comes complete with bits of chips, scampi, batter, and whatever else has been cooked in it.  It can be really very lumpy in places.

The blue barrel has an outlet about 50mm up from the bottom to allow filtered oil to then be directed into another container, either to one side, or possibly directly underneath:

When you lob a load of oil into the catch filter, it looks like this:

And then very slowly (as the outlet is only 6mm diameter) drops down.  As mentioned, the 125um catches a LOT, and gives you a good indication of how dirty the oil is.  As the mesh is fairly fine, it tends to coalesce the globules of animal fats.  This is both good and bad news, as once it's coalesced enough of it, it tends to block the mesh.  If left long enough, the oil will eventually pass through, but quite often I have to have a gentle scrape at the mesh to move the grease to one side, allowing the oil to pass through.  Once it's filtered a bit, it's pretty grim.  This one had a lot of grot and grease in it:

This one is less bad, but you can still clearly see the grease building up on the mesh:

To clean this out, I use a "sacrificial" wet vacuum cleaner, which does a remarkably good job of clearing the filter.  The machine has been used to vacuum up engine oil, veg oil, greases and all sorts of other stuff and absolutely honks.  Once it's full I might just lob it in the skip and get another:

Anyway.  Once the oil has passed through that filter, it has a brief opportunity for smaller solids to fall out, and then it comes out the bottom looking a lot cleaner:

CleanER.  I wouldn't cook my dinner in it, but it's a lot better already.

Next:  The finer filter stages.

[Talbot]

Once the oil has come from that stainless mesh, it gets to sit in 25L drums to settle, and to let all the air that has been entrained to bubble out.  I find a week is more than plenty, and any longer doesn't seem to make any difference.

Next comes the multi-stage filter system.  Each 25L gets lifted up onto a high-level shelf, and then by using a dip-tube through a lid and a little bit of air pressure in the top of the barrel, 15 L is pushed over into the "header" tank:

This requires very little pressure.  The gauge I have is only 0-1 bar, but even just bringing it off it's stop is enough:

Quite hard to get a regulator to work at that pressure.

Once I have 15L in the header tank (the one that is ratchet strapped down), that then gets a 3psi over-pressure with a similar dip-tube that stops about 30mm up from the bottom, and the 15 litres is blown through three water filter housings:

It's not running in the photo (hence the reduced oil levels) but going left-to-right, that's a 50um, then a 5um and finally a 1um filter.  The oil pushes through these, and then ends up in the "footer tank", which is a 20L black container:

These are used as I don't need to see how much sediment there is in the bottom, as there isn't any.  Also, with 15L in a 20L drum, it makes pouring them into the car about 534 times easier.  Using a different colour for clean oil means I can't get the wrong container.

The stages of filtration down to 1um mean that the filter in the car never blocks.  Most paper filters in a car are around 10um, so I'm an order of magnitude better with this setup.  I prefer doing it this way, as the filters for the standard 10" filter bodies above are about £14 for 10 filters, rather than a tenner each for the car, which is about 1/3 the size.

Things I have learned about this setup:

• the 50um filter takes the absolute brunt of the solids, and has to be changed about 10 times more regularly than the smaller ones.
• If the weather gets colder between doing the 125um filter and the 50um filter, I get grease build-up on the filter face as it coalesces out more fats.  Whilst a complete ball-ache, as it blocks the filter solid, it can be scraped off and the filter re-used.
• Blowing the filters backwards with compressed air is remarkably effective for cleaning.
• Oil gets absolutely everywhere.  You just have to accept that and do your best to keep everything clean.

I use compressed air over the tanks rather than pumps as it means you can run a compressor for 2 mins and then when filtering the entire system is silent.  It also means that there's nothing to go wrong/overheat/explode, as once the header tank is empty, the compressed air just bubbles through the filters (hence the oil levels being low in the photo above) and once the compressed air reservoir is empty, nothing more happens.  No switches, no sensors, nothing.

Thus far, I think I've "processed" about 1000 litres of oil.  Other than the oil, the costs have been:

• initial setup of the filter housings and 3x10 packs of filters:  approx £100
• Various fittings that I didn't already have:  £20
• 15 black barrels and about 30 25L barrels: £25
• and a couple of units of electricity for the compressor.

Pretty much everything else I already had, but even if you started from nothing, it wouldn't be prohibitively expensive.

Next (but not tonight) the issues with burning Veg of any sort in a diesel engine.

[Talbot]

The reason for the header tank being ratchet strapped to the shelf:  These containers are not designed for pressure, and if you put even a couple of psi in them, they do this:

The strap stops that from happening, keeping the dip tube pointing at the bottom of the tank and not the opposite corner!

[jonathan_dyane]

Great set up, I used to run a disposable  ex-minicab Xantia on WVO when I was a student, this brings back memories of everything being covered in sticky greasy dirty mess 😜

[Bradders59]

Join the Vegatableoildiesel forum. There is a wealth of knowledge & experience there.

My setup was simple Kitchen sieve on top of a 25 micron bag filter. then through a 10 micron, then 5 micron bag filter.

Had to keep it simple as it was stored in the boot of the car and filtering done in an outbuilding at work.

I never found oil from any Chinese restaurant worth the bother. Always far to much fat in it to be worthwhile.

Indian restaurants usually much better, and curry smelling exhaust was a hoot at traffic lights.

[Stinkwheel]

As always @Talbot shows us the wrong way to do things the right way (a compliment if it wasnt clear) with an excellent write up. Long may your Merc smell like a chippy

[horriblemercedes]

I've always been fascinated by this as a hobby but have never tried it as I don't really have a source of waste oil - at least not in the quantities needed to run a car. I don't know what new oil costs if you buy in bulk, but I know that oil at Aldi is more expensive than diesel (138.6p/litre for diesel two days ago vs 185p/litre for vegetable oil in Aldi)

 

If I did have a good waste oil source, I think I'd be constrained for space at present (I don't have any more storage space, simply!)

 

I would love to try it though

[Floatylight]

In early 2000's  a Friend of mine used to work in a building which was shared by am energy efficiency / renewables charity and they had a biodiesel tank bought in I think from Rix.

He ran his 306 on bio for at least 50k miles on this bio and it ran really well and as the oil was sourced from Pataks it always had a rather pleasing aroma to the exhaust.

Great write up @talbot really informative

[castros_bro]

@explosive-cabbage and co used to run wasteoil 205s. 

[cobblers]

16 hours ago, Talbot said:

This requires very little pressure.  The gauge I have is only 0-1 bar, but even just bringing it off it's stop is enough:

Quite hard to get a regulator to work at that pressure.

 

For pressures as low as this you'd probably be best off with a weighted overpressure regulation system like a pressure cooker. You'll waste some air but you'll be able to wander off without having to babysit the airflow.

Alternatively about a 70cm column of water will do the same. 

 

[Talbot]

31 minutes ago, cobblers said:

For pressures as low as this you'd probably be best off with a weighted overpressure regulation system like a pressure cooker. You'll waste some air but you'll be able to wander off without having to babysit the airflow.

Alternatively about a 70cm column of water will do the same. 

 

It just about works from a pressure regulator on the compressor.  I plan to get a propane regulator in the fullness of time, as 37mbar would be about ideal, and of course a propane reg can go fro. 6bar down to 37mbar quite reliably.  I may see if I can get a variable propane one, as that would be perfect.  There is air consumption, so a column of water isn't ideal.  Plus I want to keep water away from this system!

Tbh the air pressure is only to speed things up.  It would all work on gravity if I set it up to do so, but I suspect it would be deathly slow.

[Lacquer Peel]

Very informative. Your setup looks neat.

My setup is very simple, settle in big barrels and pump out the clean oil on top, filter via bag filters into a water butt and into the fuel tank. It isn't very efficient and can be messy. 

The oil I collect is pretty clean as used oil goes, it is from a chain of pubs, they seem to change their oil regularly. 

It is soya oil, it starts to solidify at 10°c. I add about 10% petrol at this time of year to help it to settle, otherwise it would stay cloudy/slushy. 

[DeanH]

Fascinating as others have said. Something I've wanted to give a try for a while, I thoroughly enjoy saving/making money from waste. 

OM606 cars seem to be thin on the ground these days unfortunately. 

[Scruffy Bodger]

That's a comprehensive setup! When I ran it I tried various sieves and filters at first after settling the oil off next to a central heating boiler for a week or 2 if it was cold. In the end I sacked all the messing off and got my chef mate to sort it for me. As he wasn't paying for the electric he'd heat the oil in the fryers and drain it hot straight thru a decent tea towel for me, no more bits to contend with. I'd then settle it off next to the c heating boiler to let the water separate off, tip the good stuff off the top and tip the dregs into a waste bottle.

I'd then chuck it in the car with whatever mix of diesel or petrol I thought I needed for the weather we had at the time.

This was on various XUD's with zero mods, a 205, 306 and a couple of 405's they love the stuff.

[320touring]

Great thread @Talbot !

I've run a few things on veg over the years. Never with the level of preparation seen here. I imagine you have very few, if any issues using oil prepared so well.

I'd love to have space for a proper set up but the back garden is small and the neighbours are unlikely to be grateful for a setup in the communal parking area.

Re soya oil and it's ability to solidify - here's an example with stuff that was stored in the back of my s124. This Is new oil. That thing would run on whatever you chucked at it - absolutely brilliant!

 

 

I found the om612 in the ML I had was ok up to about 70% veg.

There was that one time it basically was on 100% veg..

 

I have no mechanical sympathy and it was £300😂

[DodgeRover]

I used to run on it, I used various filter bags and let gravity do the work for me. I always wanted a centrifuge to get it really really clean.

[chodweaver]

4 hours ago, DeanH said:

Fascinating as others have said. Something I've wanted to give a try for a while, I thoroughly enjoy saving/making money from waste. 

OM606 cars seem to be thin on the ground these days unfortunately. 

Thanks @Talbot!

Similarly interested - i like anything that'll save me money, esp if it's complicated!

[bezzabsa]

used to be a few places close to me doing Bio diesel, but they all died off....pity as at 65p a litre against £1.35ppl at the time was a great help running the discovery!!

[rainagain]

I twin tanked a clio when new veg oil at Costco was a lot cheaper than diesel. Used to get funny looks at the grange when I was filling the dino diesel tank I fitted in the boot. The smell used to make passengers hungry. Does anyone here make biodiesel that you can use in a modern common rail diesel? I always thought about given that a try and but there’s a few chemicals involved. 

[Lacquer Peel]

I am too clumsy to deal with neurotoxic chemicals & heat in a garden shed. 

You could thin the veg down with a strong solvent blend, petrol works well or Kerosene if you have access to it. 

Even well made bio doesn't work well with DPFs. 

[chaseracer]

@Floatylight 

Steve, didn't you run your red 306 on bio?

[Talbot]

30 minutes ago, Lacquer Peel said:

Even well made bio doesn't work well with DPFs. 

This is very true.  Good quality biodiesel is ok in common rail direct-injection engines, but as soon as you add in DPF systems or NoX reduction with adblue, it all starts to go a bit wrong.  Mechanical IDI engines are the holy grail of veg combustion, even if modified into biodiesel.

[LightBulbFun]

enjoying this writeup quite a bit, as I always loved the thought of vehicles running on Veg and alternative fuels in general, just for the sheer novelty factor of it if nothing else  

 

 

one thing I have always wondered about with regards to veg, is how compatible are big diesel vehicles to it, has anyone ever run a Routemaster or something such on Veg for example? (cc @Yoss)

do big vehicles have their own complications? is it the same where newer ones are less receptive to it? like im guessing you cant run an Dennis Trident on veg for example?

but what about say a Leyland national? ( cc @Inspector Morose )

 

[Lacquer Peel]

2 minutes ago, LightBulbFun said:

enjoying this writeup quite a bit, as I always loved the thought of vehicles running on Veg and alternative fuels in general, just for the sheer novelty factor of it if nothing else  

 

 

one thing I have always wondered about with regards to veg, is how compatible are big diesel vehicles to it, has anyone ever run a Routemaster or something such on Veg for example? (cc @Yoss)

do big vehicles have their own complications? is it the same where newer ones are less receptive to it? like im guessing you cant run an Dennis Trident on veg for example?

but what about say a Leyland national? ( cc @Inspector Morose )

 

Even ancient commercial diesel engines can be direct injection, sometimes without glow plugs so cold starting on veg would be troublesome. 

Hard starting and idling can lead to excess fuel making its way down the cylinder walls to the sump, veg & engine oil turns into a tacky and sticky substance. 

Basically any diesel will run on veg with a careful conversion though, usually a twin tank setup with a small diesel tank for cold starts, switching to veg when the engine is to temperature and purging the system with diesel again at the end of the journey or shift. 

An Invacar would go well with a little Kubota diesel I reckon. 

[riek]

How much cash does all this buggering about save you?

[Lacquer Peel]

1 minute ago, riek said:

How much cash does all this buggering about save you?

Fuel for 0-50p a litre instead of whatever it is at the pumps. 

Smug satisfaction as well. 

[loserone]

Depends how many miles you do.  We spend about 3k a year on fuel, so there's scope..

 

Edit: or more, it seems.  This is last year 

 

[LightBulbFun]

35 minutes ago, Lacquer Peel said:

Even ancient commercial diesel engines can be direct injection, sometimes without glow plugs so cold starting on veg would be troublesome. 

Hard starting and idling can lead to excess fuel making its way down the cylinder walls to the sump, veg & engine oil turns into a tacky and sticky substance. 

Basically any diesel will run on veg with a careful conversion though, usually a twin tank setup with a small diesel tank for cold starts, switching to veg when the engine is to temperature and purging the system with diesel again at the end of the journey or shift. 

 

interesting, it was something I had not heard of anyone doing, so i figured there was reason for it not being done, I appricate the insight on that  

6 minutes ago, Lacquer Peel said:

An Invacar would go well with a little Kubota diesel I reckon. 

Funny you should mention that!

 

 

even a standard Model 70 has a compression ratio of 6.7:1 pretty sure you could run that off distilled vodka/spirits if you wanted to?

 

[riek]

36 minutes ago, Lacquer Peel said:

 

Smug satisfaction as well. 

Always worthwhile!

[Talbot]

48 minutes ago, Lacquer Peel said:

An Invacar would go well with a little Kubota diesel

Had to say it didn't you!

Veg in a direct-injection engine is definitely possible, but as you say the issues are greater and it definitely has higher risk of ring gumming and other issues.  The IDI engine is so much better when it comes to veg that I don't think I would bother even trying.

It's mainly to do with the throat between the pre-combustion chamber and the cylinder.  This glows red-hot in normal service, so having atomised fuel and air going past a surface that is above the auto-ignition temperature of the fuel rather guarantees that you get complete combustion.  It's also why IDI engines need glowplugs: the pug takes on the role of the autoignition surface until the throat gets up to temperature.

Di engines are just at so much more risk of incomplete combustion and ring gumming.  Older engines are better, as they will use a pintle-type injector, which tends to keep itself clean.  Modern injectors have no such arrangement and are so very vulnerable to blocking.