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Thread: diesel knock with elsbett nozzles

  1. #11
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    Apr 2006
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    Re: Update: diesel knock with elsbett nozzles

    Quote Originally Posted by 03Hiace View Post
    I'm considering retarding the timing a bit.
    What is the stock timing spec for your model?

  2. #12
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    Dec 2007
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    Lake Macquarie (just south of Newcastle) NSW
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    Re: diesel knock with elsbett nozzles

    Quote Originally Posted by 03Hiace View Post
    The gumming (of the nozzles) problem has been there from the start. I check the spray patterns on the injectors every 5000 kms with a diesel injection specialist. The reason for this is to keep a close eye on everything thatís going on. A few times the injectors have had minimal gumming and reasonable spray patterns, a few times they are fanning a bit and once one of them was a pisser.
    Who do you use as diesel injection specialist?
    Injectors out every 5000 - I guess if I still had access to a pop tester I might do that too. However I have had no symptoms after 45,000 km in the troopy on WVO and 50,000 km in the Patrol. If you are getting symptoms and signs as you describe then it seems you are getting gumming. I would not be blaming the injectors. I would be looking at the fuel. Or maybe leaving IP and injectors full of WVO overnight.
    I am becoming convinced of the importance of not doing that, that is a thorough purge at the end of the day.

  3. #13
    Join Date
    Jul 2008
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    Nelson Bay & Sydney
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    Re: diesel knock with elsbett nozzles

    What is the stock timing spec for your model?
    Hi Tbird

    The obvious question. I'd love to know but haven't found out yet. Can anyone help out??

    Is it possible you are only HEARING the knock up to 1600 and after that the rest of the engine clatter disguises it?
    Hi Dave

    Definitely possible. I'm a novice at working with engines and listening to the sounds they make but this clatter is quiet obvious and all four mechanics who have heard it described it as diesel knock. It sounds to me like the clatter goes away rather than being covered up by other sounds. Gossie on the central coast who checked the timing also thinks it goes away. There is however another very subtle and soft sound that only happens on veg cruising at 80 - 110 k's; it sounds like small bubbles going through the "radiator" of the cabin heating system.


    Hi Nuddy

    Geoff at Mayfield Diesel in Newcastle does the pop testing.

    The elsbett injectors have performed much better than the denso ones. I'm hopeful the gumming days are over.

    The IP has always been left overnight with diesel in it.



    My main concern is the nock, which only happens on veg at low revs. I don't like the sound of it.

    What do you guys think of the timing results. 5 deg on veg at idle with a reasonable amount of advance to 10 deg but only 3.5 on diesel at idle with almost no advance to 4 deg at full open throttle.

    My fairly wild guess is that the vane pump inside the IP prefers the higher viscosity veg and is creating a higher pressure inside the IP. This pressure regulates the advance thus increasing the timing on veg.

    Why didnít the knock happen with the old injectors? My guess is the elsbett nozzles spray the veg better and so its burns faster. Just fast enough to create the knock.

    So, what do you guys make of all this? And, should I try retarding the timing?

  4. #14
    Join Date
    Nov 2007
    Location
    UK
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    108

    Re: diesel knock with elsbett nozzles

    Its common for timing chain wear to retard the timing.

    Mercedes for example quote between 1-2 degrees per 100k of miles add to this the slower burning properties of veg oil and you could be as much as 4 - 5 degrees retarded depending on the type of engine you have.

    I fitted rec'd injectors (new nozzles) to my C250D and it knocked badly, undid the pump and moved it towards the engine about 5 degrees - runs sweet as a nut and a lot more responsive on both diesel and veg
    David

    1994 Merc C250D -110k diesel, 18k miles SVO t/ tank
    1998 merc 300TD - 89k diesel, 6k miles svo blend

    And remember ~

    "if you drive a car fast enough it will last you a lifetime"

  5. #15
    Join Date
    Apr 2006
    Location
    New Zealand
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    Re: diesel knock with elsbett nozzles

    My fairly wild guess is that the vane pump inside the IP prefers the higher viscosity veg and is creating a higher pressure inside the IP. This pressure regulates the advance thus increasing the timing on veg.
    Yep, I'd agree that is what does happen. I have a gauge permanently fitted to monitor the internal IP pressure and I've also tweaked the pressure relief valve.
    I've had diesel knock some years ago with my Hiaces. The problem was coked injectors on those occasions. Most of the carbon is inside the port where the injector seats. Relatively little comes out with nozzle when its' removed.
    If you go for the retard timing idea....mark the IP flange where it is now..... before loosening and moving it!
    If it is gumming or coking, a few percent ULP in the veg will do wonders for it.

  6. #16
    Join Date
    Nov 2007
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    UK
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    Re: diesel knock with elsbett nozzles

    Yup, mark the pump in case of probs -

    You may have to loosed the injector pipes too if they are metal, on the MB you are pushing against them.

    i have found that engines with slightly retarded timing run 'softer' and a bit dull in their response, you will soon recognise the difference, MB posters in the US have reported spinning the wheels out of the garage by accident

    One other thing I did was to take the injectors to bits and clean them with petrol.

    Last edited by spock505; 13th September 2009 at 03:56 AM.
    David

    1994 Merc C250D -110k diesel, 18k miles SVO t/ tank
    1998 merc 300TD - 89k diesel, 6k miles svo blend

    And remember ~

    "if you drive a car fast enough it will last you a lifetime"

  7. #17
    Join Date
    Oct 2006
    Location
    Newcastle
    Posts
    324

    Re: diesel knock with elsbett nozzles

    I'm led the believe the Elsbett nozzles are manufactured by Bossio(spelling?).

  8. #18
    Join Date
    Jul 2008
    Location
    Nelson Bay & Sydney
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    Re: diesel knock with elsbett nozzles

    I had a play with the timing today by rotating the IP.

    Retarding the timing reduced the clatter, I think (wishful listening), but it also reduced the performance on diesel. The 0 - 100 Km/h time was up 10%.

    Advancing the timing made little difference to the clatter, but it did improve the diesel acceleration times a little and the engine still sounds good at idle on diesel.

    Both timing changes made little difference to acceleration on veg. The original timing was the best spot with just slightly less power when the timing was advanced or retarded.

    I also tried running a 10% ULP / 90% veg blend to see if a thinner fuel would reduce the clatter. It didn't make much difference.

    Maybe I just leave things how they are and put up with the noise??

    What other ideas do you guys have?

  9. #19
    Join Date
    Nov 2007
    Location
    Victoria
    Posts
    445

    Re: diesel knock with elsbett nozzles

    Hi 03Hiace,

    I had a similar injector hammer on the troopy from the first run on wvo.

    My injectors were not long reset before using wvo so should have been working well.

    I made mention of this in my HJ45 troopy conversion thread.

    As you mentioned at idle was the most noticable. All I could think of was the thicker fuel produced higher pressure in a well used ip.

    I'm use to the sound now or it has changed and the troopy is running as good as ever.

    God bless, froggo
    HJ45 Landcruiser Troopy
    Home made 2 tank system
    Blending in main diesel tank
    SVO/WVO Converted 18/01/08
    http://www.biofuelsforum.com/svo_users/3667-hj45_troopy_conversion.html

  10. #20
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,373

    Re: diesel knock with elsbett nozzles

    Even recently rebuilt injectors can cause "nailing" which is a hard diesel clatter at low - mid engine RPM (other noises take over).

    If the clatter is worse on veggie. this could be due to the higher pressures created when pumping the veggie.
    Either put up with it or have someone have a look at them.

    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).

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