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Thread: Coking and valve deposits

  1. #1
    Join Date
    Aug 2020
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    Coking and valve deposits

    Iím in a discussion on the Ford Truck Enthusiast Forums, itís primarily a Murcan audience. I had a question regarding the 7.3 and B100 that lead to a conversation cautioning me about running Bio. The man has a lot of experience and ran bio for a some time before changing to WVO systems conversions which he now does. He says bio is going to cause combustion chamber coking and valve deposits. Iíve read two studies that agree that lower Engine operating temps does result in more particulate deposits so no argument there. This forum appears the most active English language debate on bio, at least from what I could find. So Iím very interested in members experiences long term, any term in this. I have read the Sticky but the last edit is 2010 so perhaps thereís more info available.

  2. #2
    Join Date
    Apr 2011
    Location
    Lismore NSW
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    Re: Coking and valve deposits

    Ray, on this forum ran is truck exclusively on Bio from new, you should see the engine oil before he was due to change it, it was almost as clear as new oil.
    There is a massive difference between bio and bio.
    Ray has made bio to perfection, no rushing no cutting corners. Doing the 3/27, washing it until there is no soap residue and drying it. His oil itself was crystal clear.

    All of this is important, if you can't produce good bio, there is a good chance for stuffing up your engine long term. Yes it can be time consuming, we all know that, but fortunately there are technical advance we can take into consideration to reduce hand on time on the processors.
    1990 Toyota Hilux LN106 with ATG 2 tank system (sold after running 150.000 ks on mainly WVO)

    1993 Toyota 75 Series with 1 HDT conversion, 75l factory tank and a custom 170l under tray tank. (Retired with 680.000ks on the clock mostly running on BIO and on WVO)

    2006 Landcruiser Troopcarrier 1HZ with DTS Turbo Kit, 170ltr long range tank currently not converted, running on B100

    "him who never made a mistake, made no discovery either"


  3. #3
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    Re: Coking and valve deposits

    No argument from me regards to making the best possible product. There is a fundamental viscosity difference between bio and diesel with bio pouring half as fast and that affects the injector spray and the droplets in the spray that aren’t as small as with diesel. This apparently is what causes the coking and deposits. My thoughts are that heating the fuel will help thin it. I read a paper that it does. The 7.3 has the fuel rails in the heads so once warmed it should be ok. The problem as I see it is starting up cold when the thick bio is in the system right up to and inside the injectors. At this point I’m leaning toward fitting a second smaller diesel tank and running diesel at start up and stop the same way the straight veggie guys do it and have an inter cooler to thin the bio to run through the filter and high pressure pump once the engine is hot.
    Last edited by JimV8; 3rd September 2020 at 07:57 AM.

  4. #4
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    ลึก ประเทศอินเด&
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    Re: Coking and valve deposits

    On the other hand,
    I bought me Musso new and have always used low conversion biodiesel in it from "Drive-off-the-showroom-floor", 15 years and 330,000km ago.
    For the last two summers I mixed my fuel 60% Veggie oil and 40% low conversion biodiesel. That was the mixture that started cold in the morning with no noticeable difference from 100% biodiesel.
    This winter I used a 50- 50 mix of veg oil and low conversion biodiesel.
    I stopped water washing my fuel years ago.
    I have never had the injectors looked at, it jut runs and runs.

    Of course Ontario Canada has a different sort of climate than Sunny Paradise.

  5. #5
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,324

    Re: Coking and valve deposits

    Tilly,
    There is not much to compare between the Musso 2.9 and the Ford 7.3.
    The Musso has an IDI engine, and Ford 7.3 is a CRD engine, so your example is like comparing a Holden from the 70s with a current model Holden.
    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


  6. #6
    Join Date
    Aug 2020
    Location
    Huntsville Ontario Canada
    Posts
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    Re: Coking and valve deposits

    I’m not up on the terminology. However, my 7.3 is the last in the engines evolution and is turbo charged direct injection. A lift pump sucks fuel from the tank then pushes it through a big fuel bowl with the filter, atop the engine. The fuel then goes to the high pressure pump which sits in the valley and works off the engine oil pressure. That pressurizes the fuel rails to 20k psi, and those are cast in the heads. The injectors are two phase electric with a big spring that boosts the pressure even higher. A preliminary squirt starts the process and is followed by the main charge.

    edit: I was slightly off in the description of the 7.3 fuel injection, close but off. Here’s the real deal, http://www.trucktrend.com/how-to/exp...n-systems-work
    Last edited by JimV8; 5th September 2020 at 01:41 AM.

  7. #7
    Join Date
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    Location
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    Re: Coking and valve deposits

    Now I’m mixing two conversations on two continents. The man on the Ford enthusiast site came up with a good idea to clean up the combustion chamber deposits. This applies to all cars and trucks, especially direct injected that invariably have EGR systems. The solution is methanol/water spraying the intake charge. Actually water works just fine, and it’ll reduce Exhaust temperatures too. I think it only needs to be engaged occasionally to do the trick.

  8. #8
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,324

    Re: Coking and valve deposits

    Quote Originally Posted by JimV8 View Post
    Now Iím mixing two conversations on two continents. The man on the Ford enthusiast site came up with a good idea to clean up the combustion chamber deposits. This applies to all cars and trucks, especially direct injected that invariably have EGR systems. The solution is methanol/water spraying the intake charge. Actually water works just fine, and itíll reduce Exhaust temperatures too. I think it only needs to be engaged occasionally to do the trick.
    Jim,
    Water injection is a long established method of a. Increasing engine power and b. Cleaning the combustion chambers of your engine.
    I used a switch on the throttle to inject water when at more than 50% power. I also had a boost switch that was in series with the throttle switch to prevent injection when the ignition was on but the engine is not running. I have not installed on the replacement vehicle yet.
    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


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