Following our recent article outlining how biodiesel or RME (Rape Methyl Ester) could become a viable fuel for farm machinery, we’ve had questions from readers asking just who approves its use.

Here are the responses:


John Deere

John Deere first showed a biodiesel-fuelled 7600 tractor working on the demo plots at the 1994 Tillage events and revealed that there was no loss of power through the use of RME.

All tractors produced since 1989 and before the 2002 introduction of common-rail injection systems are capable of running on pure biodiesel, with some minor modifications.

However, later models fitted with common-rail engines are only approved to burn a 5% blend.


New Holland

New Holland approves the use of biodiesel blends of up to 20% (B20). All New Holland equipment currently in production and powered by CNH engines, including common-rail, can run on B20 without modifications, alterations to service schedules, restrictions on operating temperatures or additional warranty.

Blends greater than 20% will soon be approved subject to the purchase of an extended warranty.


Case IH

Although all current Case and New Holland tractors use identical power plants, Case only approves the use of a 5% biodiesel blend for common-rail engines. This can be extended to 20% for non-common-rail units. Field testing of 100% biodiesel is under way.


Massey Ferguson

Sisu Diesel engines that were fitted to most MF tractors can run on 100% biodiesel provided the service interval is reduced by 50%.

Tier III Sisu Diesel engines which use common rail injection systems can run on a 20% blend of biodiesel. These engines are fitted to new MF 6400 (6485 upwards), MF 7400 (MF 7485 upwards) and MF 8400-series.

All Perkins engines used in Massey Ferguson machines can run on a blend of 5% biodiesel.


Fendt

All Fendt tractors produced since 1995 can run on 100% biodiesel. Tractors older than this are capable of handling it with certain modifications – contact your local dealer.

Latest Vario models use Deutz common-rail power-plants. These can also handle 100% biodiesel because they use twin oil-lubricated fuel injection pumps, thus overcoming the problems of fuel lubrication and rubber seal degradation.

Because of biodiesel’s strong solvent properties it can cause engine oil dilution. This means oil change intervals must be halved.

After the first couple of hours with biodiesel, Fendt recommends changing the fuel filters. For further information, the company offers a user’s manual appendix.


Valtra

Valtra tractors equipped with common-rail engines can be run on up to 20% bio-diesel. All other engines can be run on up to 100% biodiesel.

Engine performance with bio-diesel is the same as with mineral diesel.

Sister-company Sisu Diesel is continuing tests with biodiesel. It is possible that greater concentrations of biodiesel could be used in the future. The previous limit for common-rail engines was a blend of 5% biodiesel.

Valtra’s engines do not need to be modified before using biodiesel. However if a blend of more than 5% is used, the engine oil, oil filter and fuel filter must be changed twice as often as normal.

In addition, Sisu Diesel recommends that a separate pre-filter be fitted if biodiesel is used regularly. The water filter should be checked frequently, as biodiesel is more liable to absorb condensed water than normal diesel fuel.

DO THE FIGURES STACK UP?

Not including fuel duty, biodiesel production costs currently hover around the 50-60p/litre mark.

Because mixing the fuel with rebated red diesel can affect the dye, blends attract a duty rate of 53.27p/litre – over 6p more than the standard road fuel rate.

Clearly both the production and tax costs make biodiesel’s use as an agricultural fuel unviable for now.

However with the Chancellor’s pre-Budget report likely to announce a review of the duty situation for blends and as mineral diesel prices continue their inevitable upward spiral it’s likely to become a more attractive proposition.


Same Deutz-Fahr

All tractors marketed under the Deutz-Fahr, Same, Lamborghini and Hurlimann brands equipped with Deutz engines are now able to run on fuel blends containing up to 100% biodiesel.

The key to this is the engines’ fuel injection systems, which use injectors fed from individual pumps. Deutz says that this is a system which can guarantee reliability when operating with biodiesel.


McCormick and Landini

All McCormick and Landini engine suppliers – Perkins, EEA and Cummins – allow the use of a biodiesel blend of no more than 5% Methyl Esters and 95% EN 950 mineral diesel fuel. Conditions apply, including fuel storage methods and engine servicing intervals.

Regular oil sampling is recommended. Failures that can be attributed to operating with biodiesel will not be covered by themanufacturer’s warranty.


Perkins

All current Perkins engines can run on a 5% biodiesel mix without loss of performance or warranty invalidation. Although the energy content of biodiesel is 8-10 % lower than that of conventional diesel, at a 5% blend any loss of power will be negligible and operators are unlikely to notice any marked deterioration in performance.

Service intervals will remain at 500 hours or as otherwise previously specified.

Trials of fuel with a higher proportion of biodiesel are ongoing and Perkins expects to make a statement in the New Year.


Cummins

All recent Cummins power-plants (as used in McCormick and JCB tractors) are capable of handling up to 5% biodiesel.

The company is looking at the possibilities of increasing this.

Biodiesel has an aggressive solvent nature. This, combined with the reduced lubrication properties of low sulphur mineral diesel, can have a detrimental effect on fuel injection system seals.

FUEL QUALITY IS KEY

All the major manufacturers were keen to point out that RME must meet EN 14214 specifications.

Unrefined cold-pressed vegetable oils are not included in any brands’ biodiesel approval.

A group of fuel injection specialists, including Bosch, Delphi, Siemens VDO and Denso, warn about the quality of the final fuel.

Of particular concern is the oxidative stability of blends. When mixed with low sulphur diesel, biodiesel can become more prone to deterioration.

This means that the fuel can become dangerously corrosive and gums can form to block filters and cause coking.

Biodiesel can also corrode painted surfaces, plastics and rubber, so extra caution should be taken when filling the fuel tank. On the other hand, biodiesel degrades naturally, so any overflow can be rinsed off.