Veg oil & bio diesel

xantia78 · Post by **xantia78** » 23 Sep 2008, 22:42

I see a few people are running their cars on veg oil Is it worth looking into?

What are the advantages and disadvantages?

Just for anyones reference, if you can find a biodiesel plant near you, the government will give you a personal tax fee allowance per year. I cant remember how much though, it has to be bought in jerry cans and is then classed as generator fuel, thus no duty!

They will pump it into your car, but you then have to pay the duty

Xaccers · Post by **Xaccers** » 23 Sep 2008, 23:29

If you use less than 2500L a year (veg or biodiesel) then there is no duty to pay.
You're responsible for keeping simple records though and informing HMRC when you use more than 2500L and then paying the 50(ish)ppl duty which of course makes it more expensive than diesel in most cases.

Veg oil from Costco is currently 79.5ppl (20L boxes of it for £15.90)
It's more lubricating than diesel, so is reportedly better for your engine.
The CO2 released is the same CO2 that was absorbed by the plants used to make the oil, so it's considered CO2 neutral and so better for the environment.
It's produced for food rather than fuel, so from sustained sources.
New vegetable oil is known as Straight Vegetable Oil or SVO.
It's hydrophobic, so does not like mixing with water.

Waste Vegetable Oil (WVO) is what chip shops discard.
There are many companies out there who "treat" it to varying degrees, removing debris, water and acids (with varying levels of success).
Several members here use WVO, personally I don't because I have easy access to SVO from Costco.
It can be cheaper than SVO.
It's less hydrophobic than SVO and unless treated can contain quite a bit of water and acids from the foodstuffs which were fried in it.

Biodiesel, personally, I wouldn't touch it.
It's normally produced from WVO that's been fully refined into something that's supposedly the equivalent of diesel.
It can damage rubber seals over time, and is hydroscopic, meaning it loves soaking up water.

It's always a good idea to keep a spare fuel filter in the car.
On Xantias, clean the fuel sender mesh (most will have some gunk on them from 10 years of use anyway) and ensure that the return pipe from the pump is clear.
When it's icy, add diesel to the fuel in the tank.

xantia78 · Post by **xantia78** » 24 Sep 2008, 08:41

Wow! Its really that simple?
So I could just clean the filter and chuck it in.
Do i need to do anything else? Will it start ok?

Xaccers · Post by **Xaccers** » 24 Sep 2008, 10:17

Start on around 50% and work your way up.
At 100% the engine "hunts" until the fuel warms up, but is fine as soon as you pull away.

If your glow plugs are on their way out, you may need 2 cycles of them being activated, in which case, replace the plugs.

Normal advice is to replace your fuel filter after about 500miles, and then as normal, checking to see how clean it is when you change it.
If 6000 miles produces a mucky filter, change it at shorter intervals.

Most vegetable oils (like rapeseed and soya) will have your car smelling like a chip shop, while corn oil apparently smells like popcorn

Village · Post by **Village** » 24 Sep 2008, 13:38

hmmmmm, popcorn

1900sr · Post by **1900sr** » 24 Sep 2008, 22:08

Don't forget that you'll need to be running an XUD engine with a Bosch pump, in practice I think this means a 1.9TD in the Xantia.

Post by **CitroJim** » 25 Sep 2008, 08:01

This excludes the 2.1TD as it has a Lucas EPIC electro/hydraulic pump. They don't like even a sniff of veg and cause serious wallet-ache if they fail.

Indeed only Bosch pumped cars. NEVER run any veg through a Lucas/Roto Diesel/Delphi pump. They die spectacularly through seizure of the rotor head. The head relies on diesel for lubrication and whilst veg has good lubricity properties, it's often too thick to adequately flow through the narrow clearances in the rotor head and it becomes starved of lubrication. The head then heats, expands, seizes and as a safety measure, shears the driveshaft to prevent damage to the cambelt/engine timing. The pump is then just a paperweight!

Lucas pumps are found usually only on the non-turbo and low pressure (SD) Xantia. I've never seen one on a Xantia 1.9TD.

Many Pugs with the 1.9TD engine had Lucas pumps though.

Village · Post by **Village** » 25 Sep 2008, 09:42

my ZX TD has a lucas pump, my 406 TD has a bosch. It seems to me to be a bit of a lottery as to what pump you get....

ishish8 · Post by **ishish8** » 14 Oct 2008, 15:45

I have a ZX TD with a bosch pump - not sure on engine code but does this mean I can just stick some veg in it??

just done plugs and fuel filter so that should be fine?

where's the engine code by the way?

Xaccers · Post by **Xaccers** » 14 Oct 2008, 16:44

ishish8 wrote:I have a ZX TD with a bosch pump - not sure on engine code but does this mean I can just stick some veg in it??

just done plugs and fuel filter so that should be fine?

where's the engine code by the way?

Yes, if you're certain you have a bosch pump, go for it.
Start at 50% (or lower if you want to be really cautious) and work your way up until you're comfortable with the performance.

Check your fuel filter in 500-1000 miles to make sure it's still relatively clean (otherwise replace it).
Also make sure you use filters that don't have an open bottom and are made of plastic. The thicker veg makes it swell jamming it in the filter house, and also makes the ring of glue which keeps the filter paper in place come off.
Not sure about the ZX, but on the Xantia there's a mesh filter on the fuel pick up that gets clogged over years of normal use, it's a good idea to clean that up anyway.

KP · Post by KP » 15 Oct 2008, 08:51

ZX's and 306's are a mixed bag as some do and some dont have the bosch pumps. The xantias on the other had all seem to have bosch pumps on the 1.9td engines and the same seems to go for most 406's i've seen(not seen one yet with a lucas, but i know they exist).

As per above start with a mix and work your way up.

The stuff from costco is Soya oil which is not as good as using Rapeseed.
It gells up at a higher temp than Rapeseed and it also seems to gum up injectors due to burning as its being injected.
I've not seen this myself as i've never taken the head off an engine thats solely run on soya but i guss if you flush it every now and again with some proper diesel or sporty diesel and thrash it that it should flush it clean.

I tend to run about 1-2litres of BP ultimate every now and again when the tank gets near the reserve line and then every few months it gets a shot of 10 litres of the stuff and it dont half help the engine pull and idle smoothly but its mainly to offset the gumming effects of the soya i used for a long time and even helps with the rapeseed i use now..

As said as well keeping a spare fuel filter in the car and the allen key to replace it is a good idea if you engine starts to lose power or starts cutting out under high revs, heavey load.

I change my oil every 3-5k at the minute(barring the sump leak issue...) and i find this helps the engine a lot as you can feel it right after the service being smoother.(its cheap enough for me at about £25 a pop)
When the temps get below say 3'c overnight start to mix about 4 litres of petrol into a full tank of veg to give about 5% or so mix rate and thin the oil down enough for cold starts.

Also if you replace your plugs replace them with Bosch Duratherm as they are a smidge longer and provide a lot more heat during the glow and are well suited to veg use.

Xaccers · Post by **Xaccers** » 15 Oct 2008, 09:36

KP wrote: The stuff from costco is Soya oil which is not as good as using Rapeseed.
It gells up at a higher temp than Rapeseed and it also seems to gum up injectors due to burning as its being injected.
I've not seen this myself as i've never taken the head off an engine thats solely run on soya but i guss if you flush it every now and again with some proper diesel or sporty diesel and thrash it that it should flush it clean.

Been running Cassy on it for years with no ill effects.
When Jim and I replaced her head there were no signs of issues at all, veg or otherwise related.
If the roads are icy or there has been frost/snow I'll add some derv, otherwise it's 100% KTC veg unless I run low while away from Costco or need a fuel reciept.

KP · Post by KP » 15 Oct 2008, 09:49

Xac what did the injectors look like when you took the head off and how many miles on KTC had it done?

Sole use of soya causes the issue but diesel every now and again(as you've said) could well remove the deposits as it apparently litterly burns as its coming out of the injector nozzle leading to some carbon build up on it and the pre cumbustion chamber.
Its noted over on the veggie oil forum somewhere by HC11 i think.

Xaccers · Post by **Xaccers** » 15 Oct 2008, 10:17

Injectors were fine, had been running it for a year soley on veg before the winter months came in.
Probably about 10K or so.
Back in those days I wasn't contracting so didn't need receipts.
Saved me a fortune driving to Staines and back every day!

A lot of the concern is over E900 (Polydimethylsiloxane) which some people believe "plasticises" and gums things up.
Actually, it's a widely used organic silicone lubricant which is also hydrophobic.
It helps prevent foaming (not certain but it may actually be present in derv for the same role), and caking (stops things going gloopy).

KP · Post by KP » 15 Oct 2008, 11:36

Ahh

I have always found it thicker at the lower temps than the rapeseed i've used for a long while now, expecially when costco is a good 40min trip there and same back and their price has rocketed up above £18 a tub.

Bookers has been best value but thats still 86p/litre...