As we can see bio-fuel is a misleading term, it can cover a huge range of fuels, commercially produced fuel to relevant standards, people adding or mixing various vegetable oils to commercial diesel, and those reusing cooking oils in a raw or refined state to diesel.
Commercially produced bio-diesel produced by the big fuel producers is the best product to use, it will meet stringent standards and technical specifications, base materials will be processed accordingly to meet these standards. Pure 100% bio-diesel can be safely run in Daihatsu engines provided a few precautions are taken, these are nothing prohibitive, and most people can perform these simple modifications.
Back yard commercially produced bio-diesel operations raise more concerns, quality of the product varies from producer to producer, these, generally lack the development and the technical expertise of the big fuel producers. Many back yard or small producers will produce a quality product meeting the relevant standards, and many will not, a large number lack the technical expertise of the big boys. Many producers will try to cut corners in the production of fuel by sourcing sub standard raw materials, using inferior processing chemicals, and poorly finishing the fuel in an effort to make a quick buck.
As we can see a combination of factors conspire against us, as well as giving the reputable producers a bad name, and the industry a poor image; they can leave us with seriously expensive repair bills for our engines.
Those buying various vegetable oils from supermarkets or wholesalers in quantity generate even more problems by mixing these products with commercially available diesel. Quality and variable chemical composition is the greatest problem as standards vary from country to country, something sold as pure sunflower or rapeseed oil, which are the best base oils to use, may only be 85% pure oils, and may contain other oils such as soya, nut, or palm oils. Soya, nut, or palm oils are detrimental to most engines, and as there will almost certainly be other preservatives in these oils, compounds the problems with their use by mixing with commercial diesel. It is these additional contaminants within the base oils which will cause problems with both the fuel injection system and combustion characteristics of most diesel engines. Vegetable oils have a higher viscosity, or in simple terms, are much thicker than commercially available diesel fuel, and, along with the other unknown contaminants will eventually lead to engine problems in the long term.
Long term testing by several reputable organisations has confirmed these long term problems, many have been testing for in excess of 15 years, and the problems encountered by all of them are similar.
The used cooking oil boys are at the greatest risk, as well as the problems highlighted above, they face even more uncertainty as to the quality of the base product; is it pure sunflower or rapeseed oil, or as in most cases with fast food outlets, is it the cheapest oil they can buy. This uncertainty of the base product; and the unknown chemical composition is a major problem in itself, but we have to factor in the additional contamination from the cooking of a variety of foods, and the degradation of the oil due to the continuous heating and cooling.
In conclusion, the best supplies of bio-fuels are from the large fuel producers, and the reputable smaller scale operations, these refine their products to the relevant fuel standards, and will undoubtedly produce quality products for our engines. Unrefined oils added to commercial diesel lack any quality ranging from the contamination from additives to the base oils themselves. The best base oils to use are PURE sunflower or rapeseed oils, the ones best avoided are those containing palm oil, animal fats, nut oils, and tallow.
All the above oils are suitable for use in STANDARD Daihatsu engines if they are correctly refined and processed to the relevant standards, these standards are as follows:
EN590 (2000)
EN 590 is the current standard for all European commercial diesel produced for road vehicles, and is in force in all European countries as well as Czechoslovakia, Iceland, Norway, and Switzerland. This standard allows the blending of up to 5% bio-diesel into the fuel, and this is routinely done in France.
DIN51606
DIN 51606 is the current German standard for bio-diesel, this is considered to be the highest standard, and is used by the majority of car manufacturers as evidence of compliance for fuels used in their vehicles. Bio-diesel produced by the large fuel producers, or the reputable smaller scale producers will meet or exceed these standards.
EN14214
EN14214 is the recently finalised European specification for bio-diesel, it is broadly based, and similar to DIN 51606.
Knowing the specifications required, we can now ensure our chosen suppliers meet these standards, any reputable supplier of bio-diesel will maintain quality reports of the batch testing of these fuels. Reputable suppliers conforming to these standards will supply us with copies of these documents upon request, those not willing to do so will invariably have something to hide, and should be avoided.
Now we know the specifications, what does this mean in real terms, and how does this affect our vehicles:
Bio-diesel has a higher viscosity than commercial diesel, or in simple terms it is thicker, it contains up to two and a half times more water than commercial diesel, and has a higher flashpoint, it contains considerably less sulphur and carbon residue then commercial diesel. Bio-diesel is a natural cleaner, and attacks rubber derived components, these expand over time, and eventually become loose on push fit connections such as the flexible joints on fuel lines, or reconditioned fuel injection components. Bio-diesel does not burn quite so well in Daihatsu engines, and although it will lose around 5% of its power output, this will not affect most users, but will produce more combustion deposits which will be collected in the engine lubrication oil.
Ancillary components are the most problematic, as many vehicles have had many owners, and often worked hard on and off road, most will not have a full service history, many will have been repaired due to high mileages, and from off road damage. This presents us with additional problems, as earlier discussed, this engine and its ancillaries are a “world” engine, and were designed to operate in a wide range of operating conditions, and fuel types, totally original injection system components will cope with bio-diesel.
Has the injection system been repaired while owned by a previous person or company, or have you repaired or replaced fuel system components, this is where the variables, and potential for trouble arise. Many independent fuel injection specialists will use lower quality components in an attempt to lower costs, these are fine for European diesel fuel, and are manufactured to European standards, this was fine for most people, but these components may not be suitable for use with bio-fuels. Have you or a previous owner suffered from rusted metal fuel lines and replaced them, and while you are they were at it, replaced all the flexible fuel hoses with new rubber ones in an attempt to renew the entire system and do the job properly. Here we can identify some of the potential problems which may arise.
Using the commercially produced fuel which comes into use on April 15th and contains 5% bio-diesel may cause us problems, so how can we defend against this.
Before switching to Bio-diesel a few precautions can be taken, assuming you have owned the vehicle from new, and it has had no work on the fuel system, and is mechanically sound, a few things can be undertaken.
Replace the fuel filter with a new item before using bio-diesel, the cleaning action will dislodge a large amount of deposits left by the original diesel, the new filter will catch these and prevent them from entering the fuel injection pump.
If there is any deterioration in performance, or after 750-1000 miles after switching to bio-diesel, replace the fuel filter again.
Switch the engine oil from a good quality mineral engine oil to a good semi synthetic oil, do not use fully synthetic oil as these engines are not suitable for these oils, replace the oil filter as well. Semi synthetic oils will disperse a large proportion of the additional contaminants left by the poorer combustion of the bio-diesel, and suspend the others it does not break down until they are trapped by the filter.
If the cam belt is coming up for replacement, replace it, the thicker bio diesel puts a larger load on the fuel injection pump, this additional load may cause the belt to snap as it nears the end of its life.
Servicing requirement alterations will be a good precaution to take to defend the engine, these would include:
Depending on engine servicing intervals, reduce the service intervals from 6000 miles to 5000 miles, or on earlier engines from 3000 miles to 2500 miles, for its full service.
Drain the fuel filter’s water trap more frequently, as the bio-diesel has a water content of up to two and a half times that of commercial diesel, do this monthly as it only takes a couple of minutes to do.
Replace the cam belt at 50,000 miles instead of the stated 60,000 mile intervals, due to the extra strain on the cam belt which drives the fuel injection pump.
Generally keep an eye on the fuel pipes, due to demand for these vehicles in the European market, some were fitted with rubber fuel hoses from new.
Those vehicles doing small mileages need their oil changing at least twice a year, bio-diesel contaminates more, and this causes the engine oil to degrade quickly, in addition to this run the vehicle monthly, for at least 20 miles at motorway speeds. These types of running will help the engine oil to burn off a large proportion of contaminants, and lengthen the life of the engine oil. Those vehicles doing normal mileages need not do this.
Put a quality fuel system cleaner through the system twice a year, this will clean the additional deposits from the combustion chamber, pistons, piston rings, valves, and the exhaust system, do this as you are about to change the engine oil and filter.
Servicing requirements for those vehicles using unrefined oils such as vegetable oil from the supermarket, or in quantities from wholesalers, mixed with commercial diesel, or those using unrefined waste cooking oil would be as follows, in addition to that listed above:
Reduce the life of the cam belt by half; change this at 30,000 miles instead of the recommended 60,000 miles. Engines tested record a far greater loading on them due to the higher viscosity of the mixture, cheaper belts will often fail prematurely, this is mainly snapping or stripping of teeth, use only the best quality cam belts, and idlers or tensioners. Refined oils produced to the relevant standard reduce the viscosity of the oils to a level just above that of normal commercial diesel.
Reduce the engine oil and filter, and the fuel filter servicing intervals to half, this is due to the fact that most unrefined oils contain large numbers of specified and unspecified pollutants, as well as unrefined free fatty acids, glycerine, and water in varying amounts. Waste cooking oils can be over used, and this increases the free fatty acids in the oil, in addition many cooking oils contain substances such as lard, palm oils, nut oils, tallow, and a variety of animal fats; some are present in the base oil, others may be introduced by the cooking of food. Most unrefined oils contain hard particles which are small enough to pass through the fuel filter, but are hard enough, and abrasive enough to cause premature wear on the fuel injection components. Other major problems with using unrefined oils is the accumulation of the fuel oil in the engine lubrication oil, this necessitates the more frequent oil changes.
Run a fuel system cleaner through the fuel system before each oil change, this will help with the removal of many of these accumulated deposits, higher viscosities of these fuels mean poorer atomisation of the fuel. This leads in turn to poorer combustion, carbon deposits on the piston rings, injector pintles, valves, and generally within the combustion chamber; leading to accelerated engine wear.