Veggie Oil in E300 Turbodiesel

[Satch]

On a slightly worrying note, do we really know what we are provided with at the pumps? Has bio diesel arrived in this country yet, and will warnings be put on the pumps that this fuel could damage your engine?

Think that is what started this off: independant fuel companyGreenEnergy sell something called GlobalDiesel. This is sold off Tesco and Sainsbury forecourts as well as a number of other outlets and others will be doubtless be jumping on the "green" bandwagon.

Contains 5% VME, hence questions in my earlier post. Could it be a rerun along of the "low sulphur" diesel fuel saga where reduction of the Sulphur content without compensating lubricity additives (e.g a modest amount of vegetable oil!) is said to cause pump wear?

 

[scotth_uk]

Super information - thanks!

 

[Busker]

Was at the Royal Norfolk Show this year and had a very interesting chat with a 'Political Advisor' from British Sugar regarding BioDiesel.

Most of the Oilseed rape that's grown around these parts gets exported to the continent and processed and some even fines its' way back here as BioDiesel - that's Green isn't it!!

If I remember she was saying that the mixture ratios over in France/Germany etc were higher than they are here - someone might like to clarify that.

She was also saying that they are trying to encourage the government to help setup processing facilities here but they seem reluctant.

My 4ps worth.

 

[Vlad]

Just to add my two penneth to the subject.

I frequent the Diesel only section on Mercedeshop.com and there is loads of info on running your car on Veg Oil, Bio Diesel etc.

Before I started running my current W124 300D on a Veg oil mix (20% mix), I did a lot of reading up on the subject (worried I would wreck my engine!) and here's what I learnt.

Mixing Veg oil with diesel does not make Bio Diesel, as has been pointed out Bio Diesel is a Rape Methyl Ester mix which involves a mix of nasty chemicals being added to Rape Seed Oil.

I understand that its because of these chemicals that RME has lower lubrication properties and is also one of the reasons why the injection pumps fail.

As has been stated RME is pretty nasty stuff.

Which begs the question why don't Bio Diesel producers just mix veg oil with diesel and call it Bio Diesel? I think this is due to the fact that some cars run well on veg oil mixes (ie MB's, Peugeots, Citroens ) whereas some others, especially those manufacturers with Lucas pumps don't, so if your going to sell Bio Diesel from a forecourt you need to make sure it will run well whatever the make of car, time of year etc.

With veg oil you have to differ the mix ratio depending on the time of year....running a 50/50mix in summer is fine as the outside temperatures keep the veg oil nice and thin, whereas in winter veg oil becomes more viscous, hence you need a weaker mix.

Looking at the veg oil forums, there are many many people running on 100% veg oil or reclaimed oil (ie; used oil from fish and chip shops etc) in the summer and many who run all year round, however, they have to fit pre heaters into the fuel system to keep the veg oil nice and runny at all times of year. Many also add a Cetane booster to the 100% mix.

There are many users who have run well over 100,000 miles with no problems and some have engines that are approaching the 400,000 mile mark.

From what I have learnt, running 50%+ veg oil in older MB engines is fine in summer, whereas the CDI engines are better off running a 10-20% mix.at any time of year.

You may get a bit of filter clogging on your first run if you run the heavier concentrations, ie 50%+ as Veg oil is more viscous and can result in a load of crud being scoured off your fuel lines as it gets pulled through.

On the heavier concentrations you may also get air leaks if your fuel lines are old, as the heavier viscosity makes the pump work harder and air can get pulled into the system through weakend O rings etc.

As for me, 20% is where I'm leaving it at the moment and the car is running really well even though it smells of a chip wagon!

 

[glojo]

Just to add my two penneth to the subject.

I frequent the Diesel only section on Mercedeshop.com and there is loads of info on running your car on Veg Oil, Bio Diesel etc.

On the heavier concentrations you may also get air leaks if your fuel lines are old, as the heavier viscosity makes the pump work harder and air can get pulled into the system through weakend O rings etc.

As for me, 20% is where I'm leaving it at the moment and the car is running really well even though it smells of a chip wagon!

I frequent the Diesel only section on Mercedeshop.com and there is loads of info on running your car on Veg Oil, Bio Diesel etc.

Hi Vlad,
Correct me if I am wrong, but aren't the majority of contributors to that excellent, very knowlegeable forum US based?

The reason I ask this is because the CDI engine is VERY new to the US. Indeed they have only recently started to import it because of problems with their fuel.

The author of this informative thread was talking about a non CDI engine using a diesel vegetable oil mixture in excess of even your recommendation. I got concerned when owners of modern Mercedes-Benz CDI diesel powered vehicles either considered, or ecommended the use of additives.

For anyone to recommend doing this is not right. There is nothing wrong in individuals using whatever fuel they want, but recommending it is another issue. (Hope I have not over stated it?)

Bye for now,
John

 

[Vlad]

Glojo,

Yes, most of the contributors to Mercedeshop are American, but you also get a fair smattering of non US contributors.

For more info on opinions outside of the US on Veg oil, you have to frequent some of the other MB forums (do a search on Veg Oil when you get into the forums),Veg oil sites, and VW and Peugeot forums to get a truly rounded opinion on the subject....I think its one of those subjects that can be debated endlessly, but I think the upshot is;

Pre CDi engines.....veg oil if fine.....% mix is down to the individual owner, but general opinion is 20% is well within the safety zone.

CDi engines which run at much higher pressures etc may have a problem with Veg oil, hence % mix has to be low......5-10% is considered to be well within the safety zone.

Disclaimer: The info above is what has been gleaned from other sites and just gives a further perspective on this interesting subject and is not to be taken as being the final word on the subject.

I would certainly agree that if CDi owners have concerns with running veg oil that they should give the subject a wide berth.

 

[230K]

hmm not sure about this. My job involves developing common rail fuel pumps and RME ( bio-diesel up to 15% rape methyl ester) is one of the fuels we use for our accelerated wear test regimes as it has a much lower lubricity than ordinary Diesel. In fact this fuel and the swedish winter fuels (which are virtually kerosene) give us a right headache for premature fuel pump failure. This problem is exacerbated at high fuel temperatures, so don't run your tank low or do lots of stop-start driving on a hot summer's day. Viscosity and thus lubricity decreases dramatically with temperature leading to scuffing of internal components. A pump seizure can also wreck your engine by preventing the camshaft from rotating, thus snapping your cambelt. You have been warned!

The other problem with rape oil is that it attacks the shaft seals and orings in the pump unless they are the later models with upgraded with viton seals. This can cause fuel to mix with the engine oil and also disastrously the opposite. I will ask a few questions at work tomorrow. It would simply not be worth saving a few quid here and there to need a new pump every 1000 hours.

As for anything with a CDi engine, avoid RME like the plague if you don't want trouble. THe Bosch CP1 pump as found in CDi models until fairly recently failed frequently in Germany with their readily available Bio-diesel. So much so that DaimlerChrysler insist on special tests for our new pump.

Rudolph Diesel's engines did not run at 4000 rpm plus, and with injection pressures of 1600 bar (23200 psi ). These are the major engineering challenges for Diesel Fuel Injection equipment manufacturers.

These fuels are not a problem for heavy duty engines (like HGVs) as their pumps can be much bigger, and there is space to have an engine oil lubrication system for the pump.

Thanks to all so far interesting topic, se97mlm are you saying above that adding 30% vegetable oil to diesel reduces the lubrication properties compared to the original diesel and could i be wearing the pump prematurely?

Thanks in advance,

230K

Update the car is running far better than it would on normal diesel, starting is slightly slower in the morning and economy seems the same 400miles and above 1/4

 

[glojo]

Thanks to all so far interesting topic,

And thank you for letting us all join in

Kind regards,
John

 

[Will]

Without wanting to butt-in on a thread which doesn't really concern me (I don't own a Diesel Merc!), there are a few things that have sprung to mind:

Although you can get by running your vehicle on bio-diesel or veggie oil, and even some people claim benefits such as reduced wear or lower emissions etc, isn't the engine and fuel system components designed to run on proper diesel?

I.e, haven't the manufacturer(s) invested millions of pounds and thousands of hours of time to develop a particular product, which is designed to run on regular diesel. With figures being bounced around of 23200 psi for injection pressure, and modern diesel engines being manufactured to close tolerences due to their increasingly high performance (turbocharged, high-revving etc), it seems risky to experiment with home brews!

What I basically mean is that there seems to be a few differences already (eg, viscosity, compositions, different opinions/facts over higher/lower lubricating properties, whether or not it can cause the fuel system to gum or clog up), and other factors such as the effects on 'o' rings and pumps etc etc.

Although it comes down to a personal decision, it seems slightly obscure to me as to why you would buy a Mercedes, choose a diesel model (already a more economical car!) and try to run it on anything other than what it is designed for!

After all, if you are talking mixes of only 10-20%, and bearing in mind the fact that you still need to buy the oil in the first place (or collect it if you are lucky!) what is the actual saving on a yearly basis for an average car user (say 12K miles per year).

Factor into this the risks (even the unknown ones!), the inconvenience (having to calculate mixes on each fill-up), the logistics of the veggie oil (buying/collecting it, mess, inconvenience etc), the smell (fish + chips anyone!) and other factors (eg, customs and excise?!?), is it really worth it?

Sorry if this seems like a suspicious and paranoid thread, but I can't help notice the potential pitfalls! Good luck if you are a veggie burner and it works ok for you, but I am just interested to hear a few more opinons on the overall benefits of this idea!

Cheers,

Will

 

[glojo]

Factor into this the risks (even the unknown ones!), the inconvenience (having to calculate mixes on each fill-up), the logistics of the veggie oil (buying/collecting it, mess, inconvenience etc), the smell (fish + chips anyone!) and other factors (eg, customs and excise?!?), is it really worth it?

Hi Will,
It is nice to see that I am not the only one who has these views, first SE97mim and now you.

All your points ae well reasoned and sensibly put, but like you say it all boils down to personal choice.

Nice speaking to you,
John

 

[steptoe]

This has been interesting reading - i ran my 1997 diesel range rover on veg oil, for 65K miles ( 40K when i bought it, 105K when sold ), never had a problem, even on the coldest days, it started on the button and ran/idiled the same in winter as in summer, i only ever used "new" cooking oil, bought in 205ltr drums, i tried the method of adding white spirit (5ml per ltr ) but found it made no difference.
I changed the fuel filter fairly frequently at first, then just left it to service schedule.
I also run my 250TD 1992 estate on it, 250K miles on the clock, approx 75K on veg oil - no problems, but there is a faint smell of frying oil when your at the rear while the engine is running .

 

[se97mlm]

In response to 230K, I think that vegetable oil has a higher viscosity than normal Diesel fuel, so is not such a problem. The real problem is with RME, which is much less viscous, thus a worse lubricator.

The way a common rail fuel pump works is with a cam with triangular rider which supports up to three tappets which in turn drive three pumping plungers. The sliding interface between the rider and the tappets is made purely by a squeeze film of diesel oil, working like a journal bearing. At 1600 bar on a 5,5mm diameter plunger, the load on that interface is 2545N, or the equivalent of a 260kg mass . If the film breaks down, which happens if the viscosity is too low then that 260 kg will cause the tappet to scuff the rider, which will in turn cause little bits of hard swarf to clog all of the precision clearances in the pump and injectors and seize the pump, often snapping the cambelt too. You will most likely have a problem in hot weather, when your fuel tank is low and at cranking or idle where the interface relative velocity is at it's lowest. Older inline and distributor pumps run at a much lower pressure, so this type of running shouldn't be a problem unless you drive a delivery van in Africa!

As an aside, did you know that it has been the case that Mercedes dealers have secretly changed fuel pumps for new ones free on some CDi vehicles at different service intervals to send the pumps back for analysis? long term durability really is still an issue.

edit: just for interest's sake, when common rail reaches 2000 bar, which is not long off, and with certain higher volume applications where the plunger diameter could be 8mm, this load will be equivalent to over a tonne !! Be warned!

Just for clarification, it is RME with the lower viscosity not vege oil, so the real warning is to those who buy "Bio" Diesel.

Is it legal to run your vehicle on Vege oil?

 

[230K]

In response to 230K, I think that vegetable oil has a higher viscosity than normal Diesel fuel, so is not such a problem. The real problem is with RME, which is much less viscous, thus a worse lubricator.

Much as i thought, the vegetable oil certainly seems to have more body to it than the diesel so in theory should provide more lubrication?

The pump on my E300TD is an in-line type and the veggie oil i am using is new at 46p/litre.

The money does not come into the decision as to whether to use it or not, the two things i have to weigh up are possible damage to pump against better driveability while on 30% veggie oil.

Brings a whole new to the term "Chipped"

Should have made this a voting thread

Cheers

230K

 

[glojo]

Should have made this a voting thread

Now if it was a voting thread I would vote for Chinese Take-Away everytime, getting fresh fish is so difficult

Still a great source of information

Regards,
John

 

[jimmy]

It is not about the money, I would like to be more environmentally friendly so using a renewable, natural fuel is a good idea to me.

Also I would like to support local/UK farmers rather than pay more money to the big oil companies.

I worked out that I could theoretically save around £600 a year in fuel costs if I were to use 10% veg oil, not really worth the bother but would more than pay for the insurance and servicing.

A Mercedes is a car like any other car, why do people think that a Mercedes is something so special and it is criminal to do anything other than what the handbook says for running and servicing? Contrary to what some of you may think, a Mercedes is not terribly different to other cars on the road.

It bugs me that people think Mercedes are so special, mechanically. They are not! Yes, they are very nice, comfortable prestigeous cars and I like mine very much

Personally I do not like petrol cars, but hey, thats just my opinion, but by having several diesel powered vehicles I have a choice of what fuel I use. Petrol cars can just use petrol, as far as I know.

 

[glojo]

I have a choice of what fuel I use. Petrol cars can just use petrol, as far as I know.

Hi Jimmy,
Everyone accepts that you have a choice, even petrol cars!! They can convert to run on LPG

My personal opinion is that some people think their cars are 'special' and indeed they are. Each to their own, I say.

John

 

[Dieselman]

Hi se97,
At long last sense raises its head. I have read a lot of messages 'claiming' how vegetable oil and bio diesel actually lubricate the fuel punp. It obviously brings the expertise into question of members making them!!!!

You are someone whose advice really should not be needed, but anyone that owns a CDI engine and has read your message and still puts additives into their engine is indeed taking a 'risk'.

I would very much like to retain a copy of this excellent, very informative message.

Thanks very much for your contribution,
John

As Vlad has commented RME Biodiesel isn't veg oil and doesn't provide the lubrication properties due to washing out the Glycerin from the veg oil. You shouldn't compare apples with pears.

In addition there has been talk of pump lubrication and O ring seals not being of the correct material for use with vegetable oils.

Bosch in line fuel pumps are lubricated by engine oil other than the pumping pistons and MB specify Viton or PTFE seals as standard for exactly the reason of running on vegetable based fuels.

If RME wearing the pumps is such a problem why hasn't it surfaced in other countries such as France that run a blend of biodiesel mandatorily?

I'm not saying anybody is right or wrong in this discussion, but we need to be careful that we are all talking about the same issue.

 

[l5foye]

Interesting discussion. I would like to make a few points.
1- I understand all diesel sold in France has a % of biodiesel in it.
2- Pure biodiesel has a higher cetane (like octane) rating than 'ordinary diesel; some cars need ignition retarded. Maybe this is why car seems livilier.
3- Some biodiesels while environmentally friendly can damage paintwork.
4- There is some 20% tolerance with diesel,unlike petrol and within that range it can still meet all requirements.

 

[jimmy]

Hi Jimmy,
Everyone accepts that you have a choice, even petrol cars!! They can convert to run on LPG

My personal opinion is that some people think their cars are 'special' and indeed they are. Each to their own, I say.

John

You still not have got my point!

Agreed, my car is special to me, your car is special to you, but mechanically my car or car is is not greatly different to any other modern car and does not need extra special MB care, servicing etc.

Yes petrol cars can be converted to run on LPG but at a cost of £1000-£2000, you can simply fill a diesel car with veg oil if you wanted, no conversion, no costs.

 

[Will]

As Vlad has commented RME Biodiesel isn't veg oil and doesn't provide the lubrication properties due to washing out the Glycerin from the veg oil. You shouldn't compare apples with pears.

In addition there has been talk of pump lubrication and O ring seals not being of the correct material for use with vegetable oils.

Bosch in line fuel pumps are lubricated by engine oil other than the pumping pistons and MB specify Viton or PTFE seals as standard for exactly the reason of running on vegetable based fuels.

If RME wearing the pumps is such a problem why hasn't it surfaced in other countries such as France that run a blend of biodiesel mandatorily?

I'm not saying anybody is right or wrong in this discussion, but we need to be careful that we are all talking about the same issue.

Some good points Dieselman. From what you say, they (the manufacturers) are working towards a solution. I.e, they are designing a fuel system that will be compatible with veggie oil/other alternative fuels, both long and short term.

No doubt, it is perfectly possible to run a diesel car on veggie oil, and indeed as has been discussed here, many people have achieved good results, but I still cannot help feeling that a typical standard production diesel engine is optimised and designed to run on proper diesel!

It is a great idea, and no doubt will be an excellent option for the future as an alternative renewable energy source. As technology has progressed, diesels have now become a serious consideration for the traditional petrol-head, and year after year, a new model causes a stir (eg 150bhp GT Tdi golf, brabus/AMG diesels, diesel Jaguars etc).

I for one hope that we start to see more research and testing of veggie/bio fuels, and can therefore have engines and fuel systems specifically tailored to suit these fuels characteristics. But as se97 has pointed out, there are some considerations to be made before simply pouring in anything into your (modern vehicle's) tank that simply makes your engine run!