Marinizing VW turbodiesel engines

Discussion in 'DIY Marinizing' started by CDK, Aug 31, 2007.

  1. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    The background for this topic is "from sterndrives to jets to surface drives" on the surface drive forum: http://forums.boatdesign.net/showthread.php?t=18742.

    I am presently converting two small VW engines (1.9TD) for their marine future and come across various issues.
    Every article I read about converting car engines points out that you should make sure the engine is in good condition, like no oil leaks, not much smoke, abnormal noises etc. But if you buy an engine from a recycling company, like I did, the part has been removed from the wrackage with crude tools like a flex and a bolt cutter. All wiring, bowden cables and hoses have been cut off, the oil has been drained and the exterior pressure cleaned. Just to start up the engine to check if it runs at all, requires the purchase of various items left in the car, like a glow plug relay, starter switch and basic wiring. Also a complete cooling system has to be built: with the 6 cut off hoses the engine was deliverd with, even a short test run might prove fatal.

    For this specific engine, a further problem is, that in the VW Transporter the engine is attached to a combined bell housing/gear box that also holds the starter motor. That part is sold separately for approx. $400 but is unsuitable for a marine engine because a marine gearbox should be attached.
    So I work on the assumption that the supplier is a decent guy until proven otherwise....

    From 1/4" mild steel plate and some 1/2" pipe I have constructed a bell housing with a large hole that fits the SAE-5 flange belonging to a Technomarine (TwinDisc) TMC60E gearbox. I have drawings available for anyone who contemplates doing a similar job.
    The bell housing also carries the starter motor on top of the gear box and serves as an engine support in combination with vulcanized rubber mounting pads.

    The standard engine coupler disk available for this gearbox is far too small to fit the VW flywheel, but after totally dissecting the clutch parts the clutch cover car be used as an adapter. A special tools must be made first to properly align the engine coupler and drill 8 mounting holes.

    The exhaust manifold and turbocharger were removed and replaced by a combined manifold/heat exchanger from Bowman U.K. This light alloy part was originally designed for the 1.5 ltr VW engine but also fits the larger models. Since the Bowman exhaust has the exit at the back of the engine and VW's manifold has the output flange between cyl. 2 and 3, the small Garrett turbocharger must move to a new location, which isn't as simple as it sounds.
    I made an adapter with a 4 hole flange for the exhaust manifold and a 3 hole one for the turbocharger, the angle between them approx. 30 degrees. The oil feed tube can be reused after heating and bending it in the desired shape, but the oil return is too short and must be newly made. VW used an armoured hose with pressed on fittings, I made it from soft copper tube, soldered to the old flanges.

    The Garrett turbocharger has a membrane operated waste gate and a fairly large cast iron exhaust gas chamber, which in the car was attached to some sort of ball joint on the exhaust pipe. I flexed off the two fingers that held the ball joint and used the lathe to create a smooth surface of nearly 2" to attach the exhaust hose later. Just above that area I drilled and threaded a 5/8" hole and made a stainless steel hose adapter for it, that connects to the raw water outlet of the Bowman manifold.

    There is some doubt in my mind about this construction, because the turbocharger will be blowing very hot gas in a cast iron chamber that has a water cooled end. But I could not come up with a better solution: the exhaust hose would burn away within minutes if no water is injected at that point, and the shape of the turbocharger is far too complicated to cool the outside surface.

    Now I am working on the next issue. Because the plumbing is totally different now, a lot of hoses are needed to connect the water pump intakes and cylinder head outlets, that are all on opposite sides of the engine. Normal hoses cannot be used because space is restricted and the engine would look like a pile of sausages, so I need to find automotive cooling hoses with molded bends at the required locations or cut them up in suitable pieces and reconnect them with steel or copper tube.
     
  2. TerryKing
    Joined: Feb 2007
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    Location: Topsham, Vermont

    TerryKing On The Water SOON

    Work!

    This is a complex project and you are well along. It is good to see someone tackle this kind of work...

    What boat will these engines go in? Are you expecting a reduction drive?

    I have thought of using this type engine in a very un-marinized form, with the original transaxle and it's reduction ratio used to drive a large diameter propeller on a large displacement type boat. I will probably try this first with some low-cost front-wheel-drive engine-transaxle package from cars in the US, perhaps next Summer.

    How hot does the turbocharger exit section get with no water cooling? Perhaps a total dry exhaust with good insulation might be simpler?

    Some photos of your modifications would teach us some new tricks, I expect.

    Good luck and hope you enjoy the work!
     
  3. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Here are a few pic's of the engine as retrieved from the VW transporter T4 and the marine engine under construction. Once the first conversion is complete and has been tested, I intend to remove all the parts again and duplicate them for the next engine. That will also be the moment to thoroughly clean the engine and paint it in some fancy color. VW-Marine paints their engines snow white, but I don't think that is such a good idea for it will already be dirty before it is installed.
    The boat the engines are intended for is a Norwegian Draco 2500 Twincab, l.o.a. 8.25 m., presently fitted with Berkeley jets and Mercruiser gasoline engines.
     

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  4. Lux_wales
    Joined: Sep 2007
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    Location: Wales UK

    Lux_wales New Member

    Hi CDK,

    I currently run a 1.9 td in a jet boat, It was an experiment and no care was taken in the installation (ripped out thermostat raw water cooled). Had I known It would work as well I may have tried harder.

    Im am currently planning on making a plate similar to yours, the one for the gearbox. I have no gearbox as I dont need one but want to make a plate for the engine mountings. My question Is do you have drawings of the fly wheel and hole dimensions/spacings. As I could then CAD and cut them correctly?

    Great Job by the way.

    If you want a laugh check out my diesel jet boat (15' hamilton single stage jet.) http://youtube.com/watch?v=OnjlnEBtqv4

    All the best look forward to your reply.
     
  5. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The attached drawings are Coreldraw 9.0 files. Not the perfect toool for mechanical drawings, I agree. If reqd. I can convert them.
     

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  6. Lux_wales
    Joined: Sep 2007
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    Location: Wales UK

    Lux_wales New Member

    Thanks CDK..................

    But I couldnt open them...do not have corel draw, and cannot find a package to open them (freeware) any chance of a conversion. If the measurments are on them, a jpeg would be fine or bitmap.

    Thanks Again.

    - Dan
     
  7. CDK
    Joined: Aug 2007
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    CDK retired engineer

    VW engine-flange drawings in jpg format. Not mentioned anywhere because it's commnon here: all measurements are in millimeters!
     

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  8. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Here are some more pictures concerning the hard labour of marinizing.
    My original intention was to complete one engine first, but delivery of some parts took longer than expected, so I started working on the other one as well. That has a totally different clutch: no surface to mount the engine coupler, so I had to make an adapter ring.
    I purchased a German book "Marinisierung" written by Lehmann and advertised as the most important manuscript about the subject. Don't know if it is translated in English, if it has not been done yet, I'd say "don't bother". Lots of blatant errors, wrong advice, no details. Anyone seriously contemplating a marinizing project already knows the general scope of such a job. The author spends a lot of words at painting the engine block with the proper paint, as if marinizing is all about engine block colors. Do not remove the VW's vacuum pump like he tells you. If you do that you rob the oil pump of its driving gear and the marine life will be over before it really started.
    The turbocharger issue is not a problem anymore. I observed a 15 years old Volvo Penta turbodiesel, in pristine condition. Everything was painted except the turbocharger that had the typical color of cast iron that regularly gets very hot. Water injection is not done in the same casting, but in a seperate unit flanged directly underneath it. The injection part was painted, so it must stay cool, there was only a very thin gasket between them with no signs of leaks. Appearantly the water cooled exhaust manifold removes so much heat that expansion and contraction in the turbocharger housing are not as large as I expected.

    Changing from gasoline to diesel doesn't only concern the power plant itself.
    The diesel has glow plugs, with a relay/timer that needs extra wires. The ignition lock/switch must have an extra position. Those from passenger cars are unsuitable because they always include a locking mechanism for the steering column, so I purchased ignition switches for a Massey Ferguson tractor.
    Glowing and starting draws very large currents and the steering position is much farther away than in a passenger car, so extra relays are needed to avoid voltage drops in the wiring.
    Also the fuel system needs to be modified. A good fuel filter and water seperator should already be present, but every diesel needs a fuel return line that leads to the top of the fuel tank(s).
     

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  9. Gerald
    Joined: Oct 2003
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    Location: Florianopolis SC Brazil

    Gerald Junior Member

    I installed a new 1.9 non turbo in a boat a while back. I did the gear box thing a little different from you. For what it is worth, I cut down an old magnesium bell housing and installed it on the engine just so I could use it to mount the starter. I then built an angle iron frame and solid mounted the engine and gear box. The angle iron frame was then mounted into the boat using rubber mounts. Kind of backwards thinking but it requires no special tools. I cut the bell housing with a grinder and cutoff blade. The cut off blade resting on a block of wood to give me uniform thickness. Don't hit any steel parts while cutting magnesium or you will burn all the hair off your arms. Don't bother to ask how I know!
    Good luck
    Gerald
     
  10. CDK
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    CDK retired engineer

    I would have preferred your solution but could only find expensive refurbished gearboxes-bell housings.
     
  11. Gerald
    Joined: Oct 2003
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    Location: Florianopolis SC Brazil

    Gerald Junior Member

    Some food for thought .................. I looks like you used a flywheel for a front wheel drive. When this motor is hooked to a conventions transmission. I say conventional only because I am old and there should always be a drive shaft with U joints exiting a transmission. The starter is mounted on the side of the motor. Like conventional ..... was. There is also a steel plate that goes between the engine and the magnesium housing. That plate has all the holes for starter etc. The plate would make it easy if you wanted to use it as a guide to build your system.
    My brand new VW 1.9 will not start without using the glow plugs. However, the only electronics on the engine is the glow plug system and the starter. I installed two relays in parallel. Sort of the old belt suspenders thing. The activation side of the relays has minimal current draw so I just used a cheap push button to activate the relays, another push button for the starter and an on off switch. Couldn't find a cheap switch that did it all.
    Gerald
     
  12. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The job is done!
    It took the better part of 3 months to plan, locate parts, have them delivered to this remote location and make what cannot be bought.
    The plumbing part which I mentioned earlier caused a lot of delay and could not be solved the way I originally planned. 1,5" Molded rubber hoses with a 90 degree bend are shown in the catalog of Gates and other manufacturers, but extensive shopping yielded only 6 out of the required12 pcs, 4 from Gates and 2 from an Italian company. For the remaining 4 hoses I used solder type copper knees with 38 mm outside diameter, intended for central heating installations. The total number of hose clamps on each engine is now 26 pcs.

    Another issue was the Bosch fuel injection pump that has a hidden electronics board, in the original car engine wired to the immobilizer unit. Peeling away the plastic housing with chisel, hammer and a Dremel tool for the finer details. revealed the usual fuel solenoid that needs 12 V to enable the fuel flow.
    The turbocharged engine in the VW transporter T4 had a control unit for the glow plugs, electrical circulation pump and EGR valve. As the latter two are not present in marine applications, I used the much simpler and cheaper glow plug relay from the T3 generation. It is an electronic timer that triggers as soon as the ignition key is turned. The timing cycle is determined by a temp. sensor in the cooling circuit.

    The small bronze Johnson raw water pump that feeds the heat exchanger I mounted at the front of the engine where the power steering pump has been. Because it should not spin faster than 2500 rpm, and the engine does over 4000, I used the original crankshaft pulley on the pump and mounter a smaller one on the engine. Of course for both sides an adapter had to be made.

    The marine gearboxes from Technomarine (now TwinDisk) have a peculiar provision to cool the oil. Instead of an external oil cooler, they use a piece of copper tube that runs across the lowest part of the gearbox. Unfortunately the tube and fittings must be purchased separately: the unit is sold with two massive 1,5" bronze plugs that must be replaced by hollow ones, O-rings and the tube. A concept that should be reconsidered: a factory installed tube would not substantially increase the production cost and reduce the risk of oil leakage. Unscrewing the plugs requires a socket wrench from which 1/4 part of the circumference is removed, otherwise it collides with an allan screw that can only be removed after the plug has been unscrewed (!) Poor engineering and totally unnecessary.

    And finally: when modifying the turbocharger as described in the first part of this thread, you should chose a standard exhaust hose diameter. I made the exhaust outlet 72 mm because a assumed there exists an 80 mm hose with 4 mm wall thickness. But my estimate was 50% off: the wall is 6 mm, leaving only 68 mm inside dia. and the hose cannot be stretched to fit over a 72 mm tube.

    The engines will now be oil sprayed and wrapped in plastic until the boat is ready for them. See "DIY tunnel drives" in the surface drive forum.
     

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  13. AShley5031
    Joined: Aug 2010
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    Location: Brazil

    AShley5031 Junior Member

    Hi CDK, in the section with 4 photos, the right photo shows a heat exchanger with a tank attached, with a radiator cap on top..which looks very like my Retipar VW diesel 1.6. Should I fit another tank to the cap outflow to catch the water thrown out? If so, shoulld this tank be pressurized? I have been given conflictiing advice....some say fit one, others say that this would only increase the internal pressure...what do you recommend?
     
  14. baeckmo
    Joined: Jun 2009
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    Location: Sweden

    baeckmo Hydrodynamics

    First, the system MUST have a controlled pressure that is above ambient! This is in order to avoid cavitation in the pump inlet and at critical loci around the cylinders, where vibrating walls may cause cavitation. The necessary pressure is specified for each engine; check the cover on a car with the same engine.

    Second, if there is a "spill collector" its cover should not cause overpressure in the bottle.
     
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  15. CDK
    Joined: Aug 2007
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    CDK retired engineer

    As far as I know, Bowman UK is the only outside source for VW heat exchangers, so all marinized engines look the same.
    The tank is meant to be pressurized and has a 2-stage cap with a spring, but it is my experience that -no matter how tight the hose clamps are- some coolant fluid leaks to the raw water section. I made an electronic level detector which started to sound the buzzer within half an hour after the tank had been filled to the brim.
    I now use the engines with the cap in the 1th, non-pressurized position and the water level stays where it is. There is no overheating issue in my two engines.
     
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