In vehicle tank mixing of fresh veg oil and pump diesel ?

  1. CompoSimmonite Member

    Messages:
    4,026
    Location:
    Werrington, Stoke-on-Trent
    I've done many tens of thousands of miles in various vehicles running on a mixture of fresh veg oil and pump diesel with splash of injector cleaner. I found even CAV pumps could handle 75:25 mix without problems ! I'd add 15 litres of veg oil to 5 litres of pump diesel in a container and thoroughly mix before adding to the vehicle. Caravan water pump was the easiest way of transferring the mixture to the vehicle tank.
    As an experiment I put 2 litres of the mix in a clear pop bottle and also added 1.5 litres of veg oil to .05 litres of pump diesel in another pop bottle - which wasn't shaken. The bottles were left in the back of a bumpy Land Rover to a while and then put on a shelf at the back of my lock-up for a couple of years. The mixed bottle stayed the same but the unshaken (other than by the vehicle) bottle has seperated out with the oil at the bottom. This confirmed, to me at least, that the secret of running on veg oil and pump diesel is to ensure fully mixed otherwise the oil will settle to the bottom of the tank and then be the first thing sucked up into the engine.
    The only "modification" to the vehicles was a water heated fuel filter off an old Peugeot.
    Unfortunatley veg oil prices rose to the point where there was little or no saving compared to pump diesel so I haven't bothered for many years.
    Today I've been to Tesco and see veg oil is now available for 70p litre - almost half pump diesel price so time again to start running on the cheap stuff :)
    With my Transcat I'm thinking of making some sort of in-tank mixer rather than having to do that in a seperate container and welcome any suggestions of how this could be done.
    Only things I can come up with is a motor with paddle or an aquarium style air diffuser that could be powered by a 12v pump. The mixing would only be needed when filling up and , say, ten minutes after so not when driving.
    Any suggestion of ways to mix in tank ?
    Thanks
     
    jerrytug likes this.
  2. hotponyshoes Member

    Messages:
    847
    Location:
    Somerset. Uk
    What about one of those cheap 12v air compressors and a hose connected to a bit of tube with a row of holes drilled in. Either fit it permently or just drop it into the tank when you fill up.
    Bubble some air through for a couple of mins and it should mix it pretty well.

    In have got a load of propellers mounted on shafts on motors but they are 230v. You could probably get a model boat one for 12v though?

    Another option would be a vibrating motor fixed to the outside of the tank somehow. Might crack the tank over time?
     
    123hotchef likes this.
  3. steviec_lj

    steviec_lj Rust Welding Professional

    Messages:
    2,013
    Location:
    Barnetby, N.Lincs
    Never really had an issue in the 94 plate Paj, chucking 40ltr of veg in and a quick drive to the forecourt for 25ltr of diesel.

    Not sure if I dare try it on the 04 L200, although I believe them to be the same engine essentially
     
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  4. CompoSimmonite Member

    Messages:
    4,026
    Location:
    Werrington, Stoke-on-Trent
    I can see another experiment brewing :)
     
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  5. Nick DV Member

    Messages:
    30
    Location:
    Southampton
    I think you're making work for yourself. I've had my Toyota 4x4 for just over 16 years and I've used all types of oil in it at various ratios up to 100% with the diesel, but I've never mixed it before I add it to the tank. Never had a problem with it in all that time, but I regularly change the fuel filter as the oil will pick up any crap in the tank.

    Now I think I may head off to Tesco ……………………….. ;)
     
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  6. johnser

    johnser Member

    Messages:
    1,658
    Location:
    North Cornwall
    Don't forget that some (most?) Diesels have lift pumps with a return hose. In which case, all the time the vehicle is being used, it's being circulated. Albeit slowly. Still better to mix thoroughly beforehand I'm sure but if I were thinking of doing similar, I think I'd try to plumb in a decent dedicated mixing pump. Into the vehicle tank. Messing about with containers and decanting is a pain and messy!
     
  7. 123hotchef Member

    Messages:
    6,416
    Location:
    Kent
    same engine different pump I do it ll the time though
     
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  8. MCKDAVID Member

    is it that critical? surely within a few miles of driving, the sloshing back and forth following the vehicle movements would mix it just fine, so no problem when running. if it's standing for any length of time it would still start whether on diesel or veg oil..
     
    Nick DV likes this.
  9. julianf

    julianf Member

    Messages:
    3,730
    Location:
    devon, uk
    If the engine is hot, then adding veg on top of the dino, and then driving for a bit should sort it out.

    Some tanks have a kind of "well" where the feed and return both go, which would hinder things, but, without that, the flow to the IP, and the return should mix things.

    The trick will be to only do it when the engine is hot. Otherwise, when it enevitabilty sucks a high percentage of veg, before fully mixing, there may well be issues. A hot engine won't be so concerned.
     
  10. Ton-up

    Ton-up Member

    Messages:
    1,230
    Location:
    Essex, England.
    Install a small electric fuel pump sucking from the bottom and putting the fuel in the top of the tank and have it running with ignition.
     
  11. knighty Member

    Messages:
    1,581
    Location:
    Sunderland

    this is what I was going to say

    I've done over 200k miles on veg oil, in twin tanked vans
     
  12. gaz_moose Member

    Messages:
    894
    Location:
    tamworth staffordshire
    how do you plumb the return line in when you have a twin tank setup?
     
  13. dobbslc

    dobbslc Member

    Messages:
    3,780
    Location:
    Hertfordshire UK
    I stick a bit in the Surf especially now as the price is cheap! I don't bother mixing anything as the crap roads will do it for me!
    I get a nice constant whiff of veg from full to empty so I think it mixes it fine.
     
  14. julianf

    julianf Member

    Messages:
    3,730
    Location:
    devon, uk
    Somthing to consider -

    If you are going to modify the fuel system, and suffer all the paperwork that entails, then you may as well just twin tank.

    In my mind there's little point in moving away from a stock system, but only in some half way. You get all the disadvantage and little of the advantage.

    If you don't want to modify the fuel system, you need to find a way to, well, not modify the file system.
     
  15. chris pruteanu Member

    Messages:
    622
    Location:
    ROMANIA
    Years ago i used veg oil from local Cosco into my ford fiesta courier 1.8 d van, it had a BOSCH fuel injection pump and no turbo being a IDI engine. After a few months running on veg oil i had to re-do all crappy push fit fuel delivery lines, fit a larger heavy duty starter motor and a 110 Ah battery ! The van ran reliably enough for almost 4 years when i sold it to gypo's and they used it for a break-in ! I wouldn't bother much with it and just use straight diesel if you want no hassles !
     
  16. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,373
    Location:
    Sheffield UK
    I used one tank to draw fuel from and feed back into and when that got low used a caravan water pump to transfer fuel from the 2nd tank to the 1st.

    You could have a siphon between the two or a pipe connecting the bottom of the tanks, in which case you could draw from one and return back into the other, which would mix the fuels better.
     
  17. owas

    owas Member

    Messages:
    1,286
    Location:
    Birmingham
    I've been looking at the 70p veg oil bottles every time I go in Tesco, diesels getting expensive ...

    I know i can just throw it in to the tank with a bit of diesel and it'll be fine but it still worries me :dontknow: 300tdi
     
  18. 123hotchef Member

    Messages:
    6,416
    Location:
    Kent
    u can do it one of 2 ways, back to either of the tanks of loop it back in
     
  19. knighty Member

    Messages:
    1,581
    Location:
    Sunderland
    lots of people loop it back, I had 2 change over valves one for feed one for return.... means you get a little mixing of diesel/veg down the return line but it's not much (separate filters for them, so it's just the veg oil in the pump in about 2 foot of fuel hose being sent back to the diesel tank)

    last setup I had I added a 3rd valve, so while I drove on diesel the veg oil was pumped up from the tank (via the veg lift pump) through the heat exchanger (heating oil from engine coolant) through the filter (to warm the filter) then into the extra valve which diverted it back down the return line

    means while I drove on diesel to warm the engine up, the veg oil in the tank/lines/filter was warmed up too.... worked really well :-)


    (I know it's not a big deal, but I was quite proud of that setup)
     
    Hopefuldave likes this.
  20. reb78 Member

    Messages:
    592
    Herts UK
    What paperwork? You should tell the insurance (although mine stated that only performance enhaning mods need to be declared) but not sure what else??

    My 200tdi has done about 100k on mixes of some SVO to diesel up to 100% SVO from this point in the year onwards (because it is warm). I had the head off about 18 months ago to do a head gasket and the cylinders still looked perfect - no signs of gummed rings or anything amiss. Your 300tdi will be fine - same FIP as mine and it will handle it fine. I keep thinking about twin tanking and have everything other than the tank (Pollack 6 port changover valve, het exchanger and heated filter), but it runs so well in the warmer weather by just chucking it in the tank that I see no need to install the extra gear.
     
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