Seems diesel waxing could be about

Discussion in 'Motorhome Chat' started by tofo, Dec 11, 2013.

  1. tofo

    tofo Funster

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  2. knokinonabit

    knokinonabit Funster

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    Thought this was a thread about hair removal. :Blush:






    .
     
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  3. pappajohn

    pappajohn Funster Life Member

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    S'funny....it was as low as minus14c the year before last here in the north east....where its supposed to be worse.

    i didnt suffer waxing....just lack of grip. :Angry:
     
  4. simsy56

    simsy56 Funster

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    And there was me, about to book in for a sack and crack..........:Sad:

    Craig
     
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  5. Larby

    Larby Funster

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    There was a high incidence of injector problems around here last winter (North Essex). Everyone claimed to have had filled with diesel from a local Shell station.

    My son has been in the motor trade 20 years and is amazed how many diesels are suffering with injector problems these days.

    Recently had Ford Mondeo lose power due to blocked filter followed by lorry that suffered same problem ?

    Yet one guy runs his Land Rover on nothing but chip fat and has no problem. It really does smell like being outside a chippy.
     
  6. pappajohn

    pappajohn Funster Life Member

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    wish my car would run on chip fat......

    local discount frozen food shop sells cooking oil at £9.95 per 10 ltrs
     
  7. Bellini

    Bellini Funster

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    My 110 runs on it, although I only ever go a 30% mix.

    Still, that's enough to save £200 a year on fuel bills if used all the time. Runs much smoother with more power, too.

    Useless in near feezing conditions, though.
     
  8. Snowbird

    Snowbird Funster Life Member

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    All my vehicles run 100% bio diesel and I have had no problems with waxing. I don't suppose it could be a batch of faulty filters could it ?.
     
  9. DuxDeluxe

    DuxDeluxe Funster Life Member

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    Trying to figure this one out as the fuel passes the CFPP test (cold filter plugging point) to be sold as pump fuel, so it is not as simple as wax.

    The RAC technical guy on radio 4 this morning said that it was more like a gel (wax is obvious!) and they thought related to the higher level of biofuels currently in pump diesel (7% max, currently). I am wondering if it is anything to do with stability issues, which you get in heavy fuels when mixed - the asphaltenes drop out of suspension. Now I know that there are no asphaltenes in diesel oil but it might be something similar

    I will ask our lab guys who test this stuff every day; they might know something that they are able to pass on,

    In any case, in the big scheme of things it appears to be a very very small problem at the moment
     
  10. Landy lover

    Landy lover Funster

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    Diesel waxing is an issue when cold weather comes - this is the 'cloud' point where minute particles of wax form or drop out and can slowly block a filter or a fuel line. The addition of biofuels to the mineral form of diesel has raised the cloud point of diesel ie made it happen at a higher temperature - also EU legislation has not only forced the removal of sulphur ( previously used as a lubricant for diesel pumps and injectors ) and now increases in the amount of biofuel in diesel from 5% to 7.5% - this also lowers the cetane level ( effectively the amount of power of the diesel ) - if you relate this to petrol the effect has been to reduce it from 4 star to 2 star. To overcome these problems they put in additives firstly to cover the sulphur angle and then to cover the cetane level. As the ambient temperature lowers additives are put in to stop waxing. This is only added when needed and only at a level that is needed - So where you to fill up in Birmingham say where it was 8 degrees and then drive to Scotland where it was -5 then the diesel in your tank would risk waxing out. Similar problems occur if a garage has 'summer' diesel in and slow sales and winter arrives. I the usual timing for some additives to be put in is mid late September the level then increases according to area and risk

    If you are in a situation where you go from a warm climate to a cold one - ie fill in Spain and return to England in the winter then you can add a treatment such as Wurths which will compensate but to work it does need to be put in before filling so that it is fully mixed.
     
  11. DuxDeluxe

    DuxDeluxe Funster Life Member

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    There are loads of papers out there about it - I think you find that the cetane number of biodiesel is in fact higher than mineral diesel. One reason why it is attractive (as well as it's lubricating properties)

    Your argument doesn't stack up about waxing in this incident, though I would agree with the general sentiment. As per my post, the fuel has to meet certain standards and this include a test for waxing - not only cloud point and pour point which have been used but cold filter plugging point. According to the RAC technical guy on R4 this wasn't wax but more like a gel that blocked the filters, which is rather strange. Wax will melt back, apparently this gel does not, which is why I drew the comparison with Asphaltenes in heavier fuel oils.

    Edit - the fuel has to meet EN590 spec, no matter what and this has minimum values for CFPP wherever you are in Europe. I would not be so sure that the fuel properties vary so much between the middle and the top of the country, but it is possible.
     
    Last edited: Dec 11, 2013
  12. Landy lover

    Landy lover Funster

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    The cetane level varies wildly between different biofuels depending on its source - the highest cetane levels recorded are those from animal fats. Generally the biofuels used in road fuels are those in the lower register and often as low as 40 these are also the cheapest and the most likely to have a higher cloud point. Commercial production of biofuel is a very different product than that produced by private users from a quality base material
     
  13. DuxDeluxe

    DuxDeluxe Funster Life Member

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    I know - it's part of my job.... The samples sat on my desk tell a slightly different story; as does the knock engine. We will agree to differ on cetane values but it is not relevant to the gel problem that is blocking some filters. There is no discernible correlation between make of fuel, grade, vehicle make or vehicle type.
     
    Last edited: Dec 11, 2013
  14. busby

    busby Funster

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    It will be nothing to do with modern engines being to refined then? Are older vehicles being affected i wonder. BUSBY:BigGrin:
     
  15. Snowbird

    Snowbird Funster Life Member

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    Mine are not just old...they are almost antique and no problems whatsoever.
     
  16. DuxDeluxe

    DuxDeluxe Funster Life Member

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    It would appear not; it is the filter blocking, not the engine - unless filters for more modern engines are finer. You would think that if it was simple wax formation, whole fleets would grind to a halt in various parts of the country. It isn't - it appears to be seasonal but without correlation as above

    I'm trying to find out a bit more within the industry - got ahead of the game with the infamous anti foaming agent in the gasoline a few years ago so am optimistic I can find something possible to publish
     
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  17. Landy lover

    Landy lover Funster

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    Filters for the modern diesel engine are substantially finer than ever before - the reason behind this is the higher delivery pressures at the injector - some pressures at the injector tip are frighteningly high with pressures exceeding 1000 psi. The holes at the tip are finer to create a better and finer misting at the higher delivery pressures. This is driven by the need to reduce emissions to comply with the latest 'Euro' spec. Most modern engines are on a common rail system. Older engines have a much simplified system.

    That is a simplified explanation
     
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  18. DuxDeluxe

    DuxDeluxe Funster Life Member

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    The injection pressure on my Mercedes is about 2000 bar 29000PSI (I had to check that but it is correct; some run up to 2500 bar 36000PSI) which shows how diesel engines have rapidly developed in the recent past. It makes sense that filters are finer as the piezo injectors now used in modern engines are really an engineering marvel. According to the RAC this problem can affect any vehicle, which also makes sense, if a gel is going to drop out of the fuel then it will block anything, in the same way that asphaltenes can bring a marine diesel to a grinding halt (although at least with a lot of these you can back flush the filter to a certain extent). Still awaiting a response from my sources on this interesting problem.
     
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  19. Jaws

    Jaws Funster Life Member

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    Ok guys.. We obviously have some experts on here, so while your minds are concentrated have a question.

    I have now changed my fuel filter twice

    On both occasions, immediately after changing the filter there has been a significant improvement in mpg figures.. And I am not talking maybe or head job ( as in a job is done so it MUST be better in my head sort of thing ) numbers but serious decrease in fuel used ( about a 20 % improvement in fact )

    Soooooo

    The filter is obviously up stream from the pump.. Tank, filter, pump, injectors to keep it simple

    Now if a filter is partially blocked it should have absolutely NO effect on the injector pump or the injectors as the fuel delivered is still ( has to be ) metered at the same precise level

    I really cannot explain why the improvement.
    I have mentioned this before but in all honesty was not convinced as to the voracity of the arguments put forward to explain the phenomena

    Soooo.. you 'fuelly' guys.... any ideas ?
     
  20. Landy lover

    Landy lover Funster

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    Ok - I will try and answer this in the simplest way so please shout if its too complicated and don't shout if its too simplified.

    The modern diesel uses in one form or another a common rail system ie the diesel is pumped in a continuous circuit from the tank through the filter into the head out of the head and back to the tank. To do this at the high pressures at the injector is not only not feasible it would be exceedingly dangerous. The delivery pressure at the head varies between different systems but is about the 30 to 40 psi and even this takes a lot of pumping to the pumps are usually multi staged so stage one would be say 25 psi then stage 2 would be say 40 psi it is then controlled by a regulator to the required pressure. Generally the filter is incorporated between the 2 stages to ensure the fuel is clean going into the 2nd stage. Right now to the injectors - there are a number of ways of boosting the pressure to the required tip pressure - electronically or mechanically or a combination of both again depending on the engine. Now when we are talking of tip pressure think of a hose pipe flowing - you reduce the end by sticking your finger over it and you get a fine spray. Simplified you get a partial increase on pressures by that. Now talk specifically land rover Td5 the tip pressure is 1750bar which is an eye watering 25382.00 pounds per square inch this is done mechanically and fired electronically - the timing and extent of the opening is controlled by the ECU.

    OK the problem I suspect you may be having is either with the pressure regulator and or the fuel source being contaminated in some way. This could even be down to the diesel bug which is a black yeast based material that lives and grows in diesel and can rapidly start to block a new filter I would suggest you cut open a filter from your vehicle and examine the contents. Any restriction/ pressure loss in the flow of diesel to the injector will have a multiplying negative effect on the final injector tip pressure and therefore the power release so an increase in fuel consumption.

    Although most manufacturers are giving massively extended service periods I always change our fuel filters at 6000 miles and carry a spare

    Hope that helps and is not too confusing
     
    Last edited: Dec 12, 2013
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