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  • Semi truck conversion

    Hello, everybody! I'm a new user.

    I converted my semi truck (Kenworth T600 with Detroit series 60 engine) to run on WVO. The fuel is heated by two arctic fox heaters, then sent through a plate type heat exchanger, then into a Racor filter with a water jacket to keep it hot.

    Everything was great for about 6000 miles, but then the check engine light came on and I started losing injectors. Took it to a Kenworth dealer and they pulled out the injectors, which were completely coked up. Carbon everywhere.

    Any ideas why this happened? Any ideas how to prevent/clean the injectors? Is my oil too dirty? (it goes through a 10 micron filter with a water separator).

    Any advice would be appreciated.

  • #2
    Re: Semi truck conversion

    I have had the same problem with my hiaces, 2.4 & 3 litre. It would coke up to the point of serious power loss with "diesel knock" as well.
    See my other posts for much more detail on that.
    As I see it now, the vege, even though it's heated to around 80c is still thicker in viscocity by about 4 times.
    I have now taken to blending and are currently using vege 75%, diesel 15 -20%, petrol 5- 10%.
    It would appear that some motors are less suited to the more viscous fuels.........and having to clean the injectors on a monthly basis was "wearing a bit thin". I can clean them in about 35 -40 mins, still a pain though.
    One thing you can do is get a thermocouple temperature guage..... available cheap from Jaycar as part of a multimeter. Tape the sensor tightly onto an injector pipe. You may need to extend the wires. It's quite amazing to see the actual temperature fluctuate. 80c should the target.
    If you are not getting enough heat, try insulation using hot-water pipe sponge rubber (plumber type). Makes a big difference with heat loss.
    Hope this helps.....let me know.

    Comment


    • #3
      Re: Semi truck conversion

      Originally posted by tbird650 View Post
      As I see it now, the vege, even though it's heated to around 80c is still thicker in viscocity by about 4 times.
      The other day I was comparing the characteristics of different types of vegie oils. Apart from melting point and viscosity, an important factor seems to be the iodine value. The higher this value, the more prone the oil is to polymerise. Possibly more so at higher temperatures. (Is that correct Tony?)

      Information on iodine values: Vegetable oil yields, characteristics: Journey to Forever . It is interesting that the German SVO (canola oil) Standard allows for much higher iodine values: between 100 and 120 g/100g.

      Comment


      • #4
        Re: Semi truck conversion

        Hi Jake. I'm not really qualified to give you a proper answer, but I was at a presentation given by Prof. Martin Mittelbach of Graz University Austria recently. I wrote some notes at the time and this is what I'm referring to now.

        For the biodiesel standards, the Euro one is the only one that specifies an iodine value in the spec. None of the others (ASTM or Australian) do specify an iodine value. This is because iodine is not present in rapeseed (the prime European feedstock), but it is in soy. An observation would be that this possibly excludes other sources importing biodiesel into Europe.

        I'm not sure how relevant this is to your question and I'm sure that Tony or others can comment better. The information I have seems to conflict with your mention of the German Standard allowing a high iodine value.
        Robert.
        Site Admin.

        Comment


        • #5
          Re: Semi truck conversion

          Robert,

          To quote from the website above: "
          Higher iodine numbers do not refer to the amount of iodine in the oil, but rather the amount of iodine needed to "saturate" the oil, or break all the double bonds."

          The point I was trying to make was that the problems mentioned might be due to the polymerisation characteristics of the oils used and possibly exacerbated by overheating the oil.

          Journey to Forever mentions: "
          Generally speaking, an IV of less than about 25 is required if the neat oil is to be used for long term applications in unmodified diesel engines and this limits the types of oil that can be used as fuel."

          The German SVO Standard applies to the use of SVO in converted diesel engines. That might explain the higher IV allowed. Canola oil meets the standard in this respect. Sunflower oil and soybean oil do not.



          Comment


          • #6
            Re: Semi truck conversion

            Jake has explained it well. I can add nothing to this discussion on IV.
            back to the original topic, greasehauler What is the temperature of the veggie oil at the injectors? Does the engine spend a long time idling? What type of oil is used?
            The answers may provide a clue as the the cause of the heavy injector coking.

            It is possible to provide a water injection system, which uses the venturi effect at the inlet manifold interface to the air cleaner. The low pressure at the end of the water tube at this location will draw in a small amount of water from a water reservoir. Water injection has been shown to assist in reducing / eliminating coking in the combustion chambers of diesel engines.
            Tony From West Oz
            Vice Chairperson of WARFA
            Last edited by Tony From West Oz; 25 November 2006, 01:37 AM. Reason: spelling & capitalisation.
            Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

            Current Vehicles in stable:
            '06 Musso Sports 4X4 Manual Crew Cab tray back.
            '04 Rexton 4X4 Automatic SUV
            '2014 Toyota Prius (on ULP) - Wife's car

            Previous Vehicles:
            '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup.
            '80 Mercedes 300D. 2 tank conversion [Sold]
            '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Engine donor for W123 coupe. (body parted out and carcass sold for scrap.)
            '85 Mercedes Benz W123 300CD Turbodiesel
            '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
            '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
            '06 Musso Sports Crew Cab well body. [Head gasket blew!]
            '04 Rexton SUV 2.9L Turbodiesel same as Musso - Our Family car.
            '06 Musso sports Crew Cab Trayback - My hack (no air cond, no heater).

            Searching the Biofuels Forum using Google
            Adding images and/or documents to your posts

            Comment


            • #7
              Re: Semi truck conversion

              Originally posted by Tony From West Oz View Post
              Jake has explained it well.
              All praise should go to you Tony. I quoted from Journey to Forever. Only this morning I found out that they took their info from one of your studies!

              Comment


              • #8
                Re: Semi truck conversion

                Hi All
                I am not so sure that Iodine value is any more than an indication of the saturation of an oil
                It will not break down anything
                It is known that saturated fatty acids will produce a better "fuel" wether used as biodiesel or SVO, besides they will have better stability as well as higher cetane numbers if they are present as single c=c bonds
                That is the up side, the down side is they will gel at higher temperatures
                The ASTM standard requires a Iodine number test
                The reason for that is so as to establish stability of the fuel come oil since iodine number was developed for edible oils
                Instability of an oil is proportional to the number of double bonds per molecule, a fatty acid with one double bond is twice as stable as one with two double bonds
                The fatty acid profile of any oil will tell you if you have a lot of double bonds in the fatty acids therefore low or high stability
                Now the iodine number test will tell you saturation of the oil, it will also indicate stability
                It is very hard for a user of WVO to know what is in the oil which is also the problem in biodiesel production from this source of feedstock WVO
                I cannot suggest what to add so as to improve the situation so as to prevent cocking up injectors
                The only thing that makes sense is heating of the oil so as to improve flow
                The reason injectors foul up is because the oil is "dripping" rather than "sprayed"
                It is well to remember that you cannot compress liquids, so whatever goes in the injector pump as liquid will find it's way out into the engine via the fuel injectors
                It stands to reason than the higher the density higher pressures will be required from the pump so as to do the job
                These pumps are designed to work with dino diesel to a very narrow range of viscosity so the closer one can get to that the less problems he will have
                I am not so sure if people really understand why we make edible oil into biodiesel, we only transesterify so as to lower the viscosity of the oil to get it close to dino diesel, no other reason
                Heating of the oil in an SVO engine makes sense, if it is comming from experience, at about 80 C, as it has been suggested all well and good
                A clear understanding of iodine value /number was needed therfore the post
                Cheers
                Chris
                Never give up :)

                Comment


                • #9
                  Re: Semi truck conversion

                  After thought, Cont:
                  It is fair to say that biodiesel users do not encounter anywhere as many problems as SVO users regarding fouled up injectors
                  If transesterification does no more than lower viscosity of the fat or oil, it stands to reason once again
                  Extensive studies carried point out it is a case of the viscosity of the oil rather than anything else
                  Cheers
                  Chris
                  Never give up :)

                  Comment


                  • #10
                    Re: Semi truck conversion

                    Thanks everyone for your suggestions. The oil I use is "mystery" oil, yellow grease. This comes from various restaurant oil collections. It's about 20% anumal fat and the rest vegetable oil. I measured the temp on it and it's about 80C (150F).

                    Yes, I did let the truck idle for quite some time. When the truck is not being driven, the driver sleeps in it and lets it idle overnight. Could that be the cause?

                    I still think that my problem is that the oil is too dirty. THe filter plugs up quite frequently and I'm just afraid that some dirt can get into injectors while I'm changing the filter cartridge.

                    Comment


                    • #11
                      Re: Semi truck conversion

                      I have heard that extended periods of idling or slow running are not recommended, for vege vehicles.
                      It's just quite possible that some oils are less easy to burn and consequently leave behind soot.
                      I'd really like to know what additives are added to diesel to keep injectors and combustion chambers clean. It stands to reason that if diesel can benefit, then vege can too. The type and amounts may be different, however.
                      Acetone is one additive that has been mentioned and has quite a good write up.
                      Acetone In Fuel Said to Increase Mileage

                      Who's using an additive/s?....let us know how you are getting on.

                      Comment


                      • #12
                        Re: Semi truck conversion

                        Originally posted by greasehauler View Post
                        Thanks everyone for your suggestions. The oil I use is "mystery" oil, yellow grease. This comes from various restaurant oil collections. It's about 20% anumal fat and the rest vegetable oil. I measured the temp on it and it's about 80C (150F).

                        Yes, I did let the truck idle for quite some time. When the truck is not being driven, the driver sleeps in it and lets it idle overnight. Could that be the cause?

                        I still think that my problem is that the oil is too dirty. THe filter plugs up quite frequently and I'm just afraid that some dirt can get into injectors while I'm changing the filter cartridge.
                        Hi there Greasehauler
                        Here is a link for a filter that will save you a lot of headaches Have a talk to the guys there
                        I suggest you fit this device before your normal filters and after your preheating system
                        These guys have modified it so it can stand alone so to speak
                        Here is the link to their site in the USA Diesel Fuel Purification Systems for all diesel engines check out the "Cyclone" Job
                        See how you go Good Luck
                        Cheers
                        Chris
                        Never give up :)

                        Comment


                        • #13
                          Re: Semi truck conversion

                          Originally posted by greasehauler View Post
                          Thanks everyone for your suggestions. The oil I use is "mystery" oil, yellow grease. This comes from various restaurant oil collections. It's about 20% anumal fat and the rest vegetable oil. I measured the temp on it and it's about 80C (150F).

                          Yes, I did let the truck idle for quite some time. When the truck is not being driven, the driver sleeps in it and lets it idle overnight. Could that be the cause?
                          BINGO!. The engine at idle does not have the ability to burn off the small amount of fuel which can dribble at 'end of injection'. A short idling time during a journey will not result in any significant accumulation of the polymerised oil. I suggest that you consider switching to biodiesel or petroleum diesel if you plan to continue the practice of overnight idling (or any extended idling periods).
                          I still think that my problem is that the oil is too dirty. THe filter plugs up quite frequently and I'm just afraid that some dirt can get into injectors while I'm changing the filter cartridge.
                          What is your oil filtering process? Do you filter before filling the tank? What degree of filtration do your use?

                          Tony
                          Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

                          Current Vehicles in stable:
                          '06 Musso Sports 4X4 Manual Crew Cab tray back.
                          '04 Rexton 4X4 Automatic SUV
                          '2014 Toyota Prius (on ULP) - Wife's car

                          Previous Vehicles:
                          '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup.
                          '80 Mercedes 300D. 2 tank conversion [Sold]
                          '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Engine donor for W123 coupe. (body parted out and carcass sold for scrap.)
                          '85 Mercedes Benz W123 300CD Turbodiesel
                          '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
                          '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
                          '06 Musso Sports Crew Cab well body. [Head gasket blew!]
                          '04 Rexton SUV 2.9L Turbodiesel same as Musso - Our Family car.
                          '06 Musso sports Crew Cab Trayback - My hack (no air cond, no heater).

                          Searching the Biofuels Forum using Google
                          Adding images and/or documents to your posts

                          Comment


                          • #14
                            Re: Semi truck conversion

                            Originally posted by Chris View Post
                            Hi there Greasehauler
                            Here is a link for a filter that will save you a lot of headaches Have a talk to the guys there
                            I suggest you fit this device before your normal filters and after your preheating system
                            These guys have modified it so it can stand alone so to speak
                            Here is the link to their site in the USA Diesel Fuel Purification Systems for all diesel engines check out the "Cyclone" Job
                            See how you go Good Luck
                            Thanks for this link. It's a good looing filter. I will contact them on Monday. Racor that I use has a similar "turbine" design and separates water into the lower bowl.

                            Comment


                            • #15
                              Re: Semi truck conversion

                              Originally posted by Tony From West Oz View Post
                              BINGO!. The engine at idle does not have the ability to burn off the small amount of fuel which can dribble at 'end of injection'. A short idling time during a journey will not result in any significant accumulation of the polymerised oil. I suggest that you consider switching to biodiesel or petroleum diesel if you plan to continue the practice of overnight idling (or any extended idling periods).

                              What is your oil filtering process? Do you filter before filling the tank? What degree of filtration do your use?

                              Tony
                              I didn't realize that I can't idle the engine for long periods. Maybe that is really my problem. Although my filtration is somewhat minimal too. Currently, I only use the Racor 1000 series filter. I do not pre-filter before filling the tanks. I do plan to add a woven cartridge industrial type filter. It is very long (about 70cm) and I welded a water jacket round the stainless steel enclosure, so it will always be hot. The woven cartrdge is 5 microns and I plan to use this filter before the Racor.

                              Comment

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