VW TDI diesel-Merc Bravo 2 outdrive for houseboat

Discussion in 'DIY Marinizing' started by jrnj, Jul 19, 2015.

  1. jrnj
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    jrnj jrnj

    Hi,
    This is my first post here at boatdesign.net. I’m currently restoring (3rd summer) a 1972 Nautaline houseboat. The boat is LOA 43ft, LWL approx. 40ft, BWL 12ft (beam 14ft overall due to cantilever side decks). The manufacturer states the weight at 24,000lbs with no fuel. The boat originally had two Chrysler 215hp gas engines with outdrives.

    The engines and outdrives have been removed and the transom rebuilt. A bow thruster (via tunnel) has been added for dockside maneuvering. The intent is to install a single diesel engine to mount up with a Merc Bravo 2 (diesel gear set) outdrive and transom plate that I have. The boat is now fitted with two new 100 gal diesel tanks.

    Since I’ve always been a sailor (this is my first power boat) 7kts looks pretty good to me. So a quick calculation shows that the hull speed should be approximately 7.45kt. The power to move the boat at this speed can be calculated/estimated at approx. 40hp. This is of course with no wind and no waves. Since the 12ft beam of this houseboat at the bow closely resembles a billboard, pushing it through air never mind a stiff breeze would require significantly more hp.

    I have read a number of very useful threads here and at tdiclub.com about marinizing VW TDI engines. Unfortunately some were a number of years old and didn’t necessarily cover some of the newer VW engines and reported engine problems. I’ve tried to limit my engine choices to the following to allow for the possibility of tuning the engine if necessary and to move ahead with the project. (specs taken from Wikipedia)

    1.9 R4 TDI PD codes BPX or BUK
    118 kilowatts (160 PS; 158 bhp) @ 3,750 rpm; 330 newton metres (243 lbf•ft) @ 1,900 rpm — BPX, BUK SEAT Ibiza Mk3 (BPX: 03/04->, BUK: 11/05-12/08) (engine exclusively developed by Audi for SEAT Sport)


    2.0 R4 TDI PD 16 valve codes BMN, BMR or BRD
    125 kilowatts (170 PS; 168 bhp) @ 4,200 rpm; 350 newton metres (258 lbf•ft) @ 1,800-2,500 rpm — BMN, BMR, BRD...


    2.0 R4 TDI CR 16 valve codes CBBB,CFGB
    125 kilowatts (170 PS; 168 bhp) @ 4,200 rpm; 350 newton metres (258 lbf•ft) @ 1,750–2,500 rpm — CBBB, CFGB Audi TT 2.0 TDI quattro, Audi 8P A3, Volkswagen Golf Mk6, Škoda Octavia RS TDI

    Since I’m trying to match the gear and propeller to the maximum torque curve at the lowest RPM (1700-2500RPM for target cruise speed of 7kts) the engine would probably only see WOT in an emergency. Problem areas that I can think of and need the most help with include:

    Mounting engine to Merc transom plate, including flywheel housing and starting motor mounting.

    Flywheel coupler to Merc outdrive

    Heat exchanger for coolant to engine, engine oil cooler and turbo

    Reprogramming the ECU (I’m a software developer so I don’t think that will be a problem given the right equipment)

    Wet exhaust


    I appreciate ANY thoughts, comments and suggestions. As of right now I’m on hold with the project until the engine is installed. I don’t want to complete the interior until I have made a couple of weeks worth of sea trials with the new engine. THANKS FOR THE HELP!
     

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  2. CDK
    Joined: Aug 2007
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    CDK retired engineer

    Any of the mentioned engine types will suit your purpose, yet all of them also have the same "problem areas".
    As far as I know there is no conversion kit on the market that enables you to attach the engine to a Merc transom housing without cutting, drilling and welding. These parts do exist of course, but buying them as spare parts will certainly spoil your fun.

    You need access to professional tools and someone who knows how to operate them. A small error in making the flywheel housing or positioning the Merc coupler on the flywheel may produce vibrations you later regret.
    The first step is finding the right donor vehicle and completely overhaul the engine. I made the mistake of taking the engine condition for granted because the seller said it was excellent.
    Once you have the clean engine on a bench you can start measuring and make drawings for the construction.
     
  3. Steve W
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    Steve W Senior Member

    I personally would steer clear of the PD engines. I have owned an older TDI Passat and currently drive a 05 Passat with the 1.9 pd engine, these things have a balance shaft which is chain driven which also drives the oil pump and apparently at some point the chain will fail and hatch the engine. There are a couple of fixes one which involves changing to a gear set and the other involves deleting the balance shaft altogether. Neither Is cheap or easy. I don't know anything about the newer engines but if it were me I would go with an earlier engine, There is a guy who has already developed a kit including a new bellhousing which I think is for the mercruiser. He has been on this forum I think and the TDI forums.

    Steve.
     
  4. jrnj
    Joined: May 2015
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    jrnj jrnj

    Thanks CDK. I've read a good number of your posts and appreciate the information. My intent is to do exactly what you suggest. Get the engine and do a total rebuild first. Even if I can't use it in the boat I'll be able to sell it and recover some of my costs. Yes I agree that the coupler/flywheel combination is critical! My son just had to replace his coupler AND transom plate because of a misalignment made when someone reinstalled the engine in the boat. This was with standard Merc factory parts! I do, thankfully, have access to the equipment and skill required to setup the coupler/flywheel. How is your project going?

    Thanks Steve. But I’m confused. Are you suggesting that the CR’s are the better engines and to stay away from the PD’s? Some seem to suggest that the timing belt is better that the chains even if the belts are considered a consumable with a definite replacement schedule.

    Have either of you heard about a company Recycled Inc. in Auburn Hills, Michigan? They are advertising a “genuine” WV industrial bell housing (Priced at $198.98) that they claim and their pictures show, a bolt pattern that seems to match up to the 1.9L VW’s. The picture and description also show a three hole setup on the bell housing for the starter. This setup would put the starter on the engine side as opposed to most VW bell housings that have the starter on the gear side. I’ve read that a Passat starter rotates in the opposite direction of the 1.9's and would be perfect for this setup. This of course would eliminate one of the problems that I mentioned.

    Once thanks again for the replies!

    PS a link to the bell housing is here: You may have to cut and paste this.

    http://www.thesamba.com/vw/classifieds/detail.php?id=1227900
     

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  5. CDK
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    CDK retired engineer

    The bell housing seems a bit small to me. As far as I know VW used larger flywheels on their diesels (seems logical, doesn't it?) so the starter bolt pattern cannot be in the same position for all engine types. Also, the VW starter has a "nose" with a support bearing and is installed in an open hole, while for this bell housing you need an open type.

    I think it is possible to have the starter motor at the transmission side when the engine is attached to the Merc transom housing but not in the 10 o'clock position shown.

    I sold my boat with twin VW diesels last year to a guy who seemed to be very happy with it. Although I warned him to be careful he left the bay at full throttle; I haven't heard from him since.
     
  6. jrnj
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    jrnj jrnj

    Thanks CDK. It seems to me that the distance between the engine and the transom with my transom plate is inches. Maybe 4 or 5. I don't know if they make a starter that small. The website showed pictures with a measuring tape. I'm going to check again and check that measurement against the flywheel. So are you out of the boating/conversion cycle or do you have something brewing??
     
  7. CDK
    Joined: Aug 2007
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    CDK retired engineer

    No, nothing new. Last year around my 72nd birthday I've decided it was time to stop and consolidate. There are still a few other projects I have to finish, but I may abandon these too. We presently have a 5.60 m. RIB with a 100 HP Yamaha: not exactly comfortable but as a means of fast transportation to nearby beaches and harbors it suits me well.

    The starter motors I used were indeed very small, they have a planetary gear which makes them quite powerful. From memory I'd say they were approx. 5" long.
     
  8. mikkijayne
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    mikkijayne Junior Member

    That bellhousing is for the 'small block' VW engines - 1.3 & 1.4L displacement. It won't fit the 1.9 or 2.0 engines.

    The VW Marine bellhousing for the 1.9 / 2.0 is part number 064 323 924C. Retail in the UK is £400 or so.

    I'm in the process of marinising an older rotary-pump TDI to go in my Dateline jet boat. The plan for that is to fabricate a bellhousing from laser-cut steel.
     
  9. jrnj
    Joined: May 2015
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    jrnj jrnj

    VW 2.0 CJAA engine for the houseboat

    Latest update. I now have a VW 2.0 Diesel CJAA for the boat. I have to buy a new turbo and ECU with programming for marine use. The same problems exist with the bell housing, coupler as well as the heat exchanger and wet exhaust. Hope to attack these this winter and have the boat in the water early spring 2016.
     
  10. FAST FRED
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    FAST FRED Senior Member

    I think you will be very low on power for most operation.

    Perhaps you could borrow a 40+ hp outboard and quick mount it to see what you will have when finished.
     
  11. jrnj
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    jrnj jrnj

    Hey Fred, thanks for the comment. I'm a little confused though. The 2L VW is 150 hp. With tuning it can be pushed up to just about 200 hp. Again I'll be happy with hull speed which should be about 8 kts.
     
  12. CDK
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    CDK retired engineer

    FF usually posts one-liners. Two lines mean he thought really long about your project!

    Do you have just the engine or are wiring and peripherals included? If reprogramming the ECU turns out to be a problem you could probably make it think it is still in a car.
     
  13. jrnj
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    jrnj jrnj

    Hey CDK, hope alls well with you! I have the engine and wiring harness, alternator, starter, fuel pump, air conditioning compressor!! and everything except a good turbo/exhaust manifold and ECU. I've contacted a couple of Malone Tunes dealers and they have said they have ECU's for the engine and will tune it for marine use. Just have to figure out which turbo would be best for the setup.
     
  14. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "The boat originally had two Chrysler 215hp gas engines with outdrives. "

    "The 2L VW is 150 hp."

    While cruising at a few K will not be a hassle , control in docking might be interesting.

    In either case the auto HP has little to do with the engines ability to push a boat hour after hour.

    Long term I would rate the VW at 1 hp for every 3 cubic inches of disp.

    If this will cruise you , it sounds good to me.

    The torque peak, roughly 2000 rpm sounds like a good long range cruise rpm to shoot for.
     

  15. jrnj
    Joined: May 2015
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    jrnj jrnj

    Hey Fred! Totally agree. HP is really of little interest to me. I'm looking for 7-8 kts. The VW 2.0L torque peaks at 1800-2000 which is where I hope to run it. Lots of torque and a big prop "should" push the boat up to hull speed. I'll let u know after I do some sea trials in the spring. As for docking the boat has a bow thruster which should help there.
     
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