VW diesel marine conversions

Discussion in 'DIY Marinizing' started by moTthediesel, Apr 6, 2006.

  1. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Ashley, you started this thread because the engine overheats and water starts leaking from the overflow. With just a small area reaching 100 C. there would be no pressure buildup because steam would revert to water the moment it mixes.
    All symptoms point to a blockage and/or insufficient flow.

    Is your cooling circuit only using the central port with the port next to cylinder #1 plugged or is that one used as well? It was intended for the car heater, which has a fairly high resistance.
     
  2. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW Marinized Diesel

    Hi CDK,

    I have just had yet another mechanic look at the engine. In answer to your question, the connection is being used between cylinder 3 and 4 for the freshwater circuit. There is another connection at the end of the block (next to No.4 cylinder) which holds the sensors but also has a small hose connection.

    This mechanic suggested swapping the injectors round to see whether the overheating follows the injector, and I will do that this weekend. But here is the thing, the temperatures around the rest of the engine seem to be all below 70 degrees, including where the sensor is attached to the cylinder head, but the temperature alarm goes off and water is thrown out of the cooling water cap. So yes, the engine is still overheating.

    It also has now developed another problem. It started to accelerate on it own just now, and it wasn't that the throttle lever was stuck. I had to turn the engine off. The mechanic today said that he thought maybe the timing belt wasn't set correctly. When I restarted the engine after putting in more water, it was very difficult to turn over and I had to put by hands over the air inlet to block the air coming in, making it easier to turn over. Maybe the engine is retarded or advanced. If I understand correctly, the engine jams on the valves if the timing belt is not in the right place.

    There is also a lot of smoke coming out of the exhaust, which is of course because of cylinder wear, which I knew about. I am really thinking that maybe I should take this engine out of the boat and re-build it. The trouble is that the boat was built with no access hatch to the engine so it has to come out and go back in pieces.

    So even if I rebuild it, I would have to dismount it and rebuild it inside the boat.!!!
     
  3. thudpucker
    Joined: Jul 2007
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    Location: Al.

    thudpucker Senior Member

    Photos!
    Some years ago I helped pull three engines out of an old Chris Craft. Three Chrysler Crown 8 cylinder inline engines and all the related parts.

    It soon became apparent to the owner that he'd be better off removing the Decks above the engines. All the damage to his boat gangways and bright work suffered as four guys struggled with those heavy parts caused him to see the light.

    We removed three Decks and lifted them out.

    Your boat is getting older now. It may be time to overhaul the deck to give you better access to the engine compartment.
     
  4. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    Thudpucker, did you send some photos attached? If so I can't access them. Could you send them to my e-mail? ashley.huggins@terra.com.br

    thanks
     
  5. thudpucker
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    Location: Al.

    thudpucker Senior Member

    No Ashly, I wanted you to send photos of your boat and engine. It would help my poor mind get an idea what your up against.
     
  6. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    If you remove an injector you need to install a new heat shield disc, they are not reusable.

    This type of engine doesn't allow more than 4 teeth timing error before the valves start hitting the pistons. When that happens, your overheating problem suddenly becomes very minor.

    Maybe it is time to get a hacksaw and make a hatch.
     
  7. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW marinized diesel

    Hi CDK, I take it that the heat shield disc is the washer that goes in first, before the injector. I already took them out when the head was re-conditioned and have not replaced them...oops! Why are they not re-usable?

    To answer your question about the fresh water cooling system, as far as I can tell, the route is like this. The pump has three hose connections, two small and one larger. The pump fits flush onto the block and pushes the water upwards inside the block. When the thermostatic valve is closed, the hot water comes out of two connections on the cylinder head, one between cylinders 3 and 4, and the other on the far end of the head, beside cylinder 4, the smaller of the two.

    When the thermostatic valve opens, the valve shuts off the route to the connection between 3 and 4 and opens the larger hose connection, which starts to suck water through the heat exchanger. The small hose connection to the end of the block appears to remain open and seems somewhat redundant in the scheme of things.

    Could the fact that the engine started to race on its own have something to do with the heat shield discs? Or the fact that one of the injectors is hotter than the others?

    You say that there is error room of 4 teeth on the timing belt. If it is too hard to turn over the engine, is this because it needs to be advanced or retarded?

    On setting the timing belt, two teeth back and it was jamming on the valves, so should I advance it one more tooth?

    I will be taking some pictures over the weekend of the boat and the engine, which will make things clearer. Thanks for your help.
     
  8. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    The discs are the seals between the (pre)combustion chambers and the injectors. When installing an injector the disc is flattened because the center is pressed inwards by the nozzle. Once used there is not enough spring action left to cope with nozzle and bore tolerances.
    With a non-sealing, wrongly mounted or missing disc, the injector heats up and the fuel boils. Then the needle valve gets damaged and the injector stays open, causing further overheating and power loss.

    To properly set the timing, you have to follow a procedure for which you need 3 special tools: a gauge to keep the camshaft in position, a locking pin for the injection pump and a clock calibrated in 0.01 mm steps. Without these you don't stand a chance to obtain correct timing.

    A source for information and tools is here: http://www.vwdieselparts.com/forum/
     
  9. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW Marinized Diesel

    Hi CDK,

    I have entered the other site you suggested. What do these discs look like? Are they of steel? Here is the entry I have added on the other site, FYI.




    Hi everyone,

    My name s Ashley, I am English and live in Rio de Janeiro. My problem is the diesel on my 35 ft Bruce Roberts ketch. I have overahauled the whole boat since buying it in November, but have yet to sail in her because of problems with the diesel engine. I started an inquiry thread on

    http://www.boatdesign.net/forums/diy-marinizing/vw-diesel-marine-conversions-11155-4.html

    CDK says I need special tools to set the timing belt, plus also he says I need to replace the "heat shield discs"

    When I took the cylinder head off and reconditioned it, I also took the injectors apart to clean them. I realize now that this may have been a mistake.

    When the engine is running, the timing having been set by eye by the mechanic helping me, number 4 injector is running hot , 100 degrees C, and the engine started to race.

    Firstly, to identify the heat shield discs, I need to indentify them...what are they made of and what do they look like?

    What adjustments, if any, do I need to make to the injectors aother than merely tightening them up?

    CDK says I need tools to set the timing correctly. He is probably right, but the mechanic showed me that if the groove on the valve cam rod is horizontal, the marks on the injector pump are lined up, with the mark on the pulley at the end of the main drive shaft in the most vertical position, then this is the right setting.

    When we set the timing, two teeth back and the drive shaft would no longer turn because it was fouling on the valves. So I am thinking of advancing it one more tooth, because the engine is very hard to turn over.

    Aside from this, if you look at the inquiry thread on the other site, you will see that my main problem is that the engine continues to overheat. That is to say that the heat alarm goes off, although the heat sensor when measured with an IR thermometer, actually shows a normal temperature of 85 c or so.

    Any suggestions?
     
  10. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    I copied an image from the internet.

    There are guys who can adjust VW diesel timing in the dark, without tools, by just listening to the engine. I am not one of them!
     

    Attached Files:

  11. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW Marinized diesel

    Baeckmo, CDK, Petros

    Here are some photos of my engine as well as the acess to it. The hoses to the pump and head are fairly visible
     
  12. AShley5031
    Joined: Aug 2010
    Posts: 29
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    Location: Brazil

    AShley5031 Junior Member

    VW diesel photos

    Here is a photo of the engine...seems I can only upload one at a time!
     

    Attached Files:

  13. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW diesel photos

    Another one from the other side
     

    Attached Files:

  14. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    VW Diesel

    One of the fresh water pump
     

    Attached Files:


  15. AShley5031
    Joined: Aug 2010
    Posts: 29
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    Location: Brazil

    AShley5031 Junior Member

    VW Diesel

    One of the salt water pump
     

    Attached Files:

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