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  1. #1
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    Default Installing new Nanni engine

    Masina is a 40 year old strip-planked yacht built in NZ. She had a Bukh DV24 installed in her about 35 years ago. The engine is raw water cooled and starting to behave as though it's ready for a major overhaul. However, I managed to acquire a Nanni 4.200 HE recently for roughly the cost of overhauling the old Bukh. The Nanni is about 20 years old but has never been run. It was bought for a project that, sadly, was never completed. So, over the next few weeks, I hope to prepare the new engine for installation, remove the old engine, renovate the engine bay and install the new engine.

    20170604_170123_HDR.jpg

    The problem I have is that I know very little about engines. So, if anyone here is willing to guide me through the process, I'll be all eyes and ears and grateful!

    I've downloaded the owner's manual for the engine and the workshop manual. However, the workshop manual has drawings of the models covered by the manual that don't seem to match my engine - so there's a bit of confusion early on.

    I've drained the oil from the engine and am about to put new oil in. Then I'll remove the injectors and put a little oil on each piston and then turn the engine over by hand. I'm not sure how much oil I should put onto the pistons for this step! As long as she turns over well enough, I'll then replace the injectors. The manual suggests installing new copper washers/gaskets and heat seals when I do this so I guess I'll have to wait til I can get those from the Nanni dealer. After that, I'll commence setting up to run the engine in the shed.

    Rick

  2. #2
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    Default Re: Installing new Nanni engine

    Is that 42hp? . A bit late now maybe, but there are shipyard breakers in India that have heaps of Bukh 24s from lifeboats that have only done a few hundred hours, being sold at generally a quarter of the new price. Have you done the prop calculations yet? How big was the last prop and what ratio is the gearbox/revs?

  3. #3
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    Default Re: Installing new Nanni engine

    Not yet. I'm currently renovating a couple of houses and have put the whole engine installation project on hold til now so I'm pretty much starting from scratch. I don't have the calcs yet but in talking to a couple of local contacts, it seems likely that the existing shaft and prop will be suitable. If not though, I'll be swapping them over too. I am planning to install a new flexible coupling in any case.

    I really picked up this engine for a very low price (a lot less than a quarter of the price of a new DV24), it weighs almost the same as the old Bukh and the new engine is complete with gearbox. Masina is a 38' yacht so a 40hp engine is pretty right - I'm told!

    Rick

  4. #4
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by RFNK View Post
    I really picked up this engine for a very low price (a lot less than a quarter of the price of a new DV24), it weighs almost the same as the old Bukh and the new engine is complete with gearbox. Masina is a 38' yacht so a 40hp engine is pretty right - I'm told!

    Rick
    But she has been using 24hp for 35 years and that is suddenly wrong? I have an option on a cheap 22hp Vetus diesel, but according to calculations, i will never be able to use it all. Projected power use even at full load to hull speed was only 12hp, allow for losses and a bit extra and even 16hp is twice as much as the charts show for average cruising load. I am certainly no expert, but i reckon unless you fit something like a Bruntons auto prop, the engine will either run under its best rating, or you will have to fit a much smaller prop to reach full HP, consuming far more fuel than might be needed and using a prop with far less bite than might be usefull. If it came at a bargain price, an auto prop would be a good purchase.

  5. #5
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    Default Re: Installing new Nanni engine

    It is a marinised Kubota base engine, so parts should be available at the local tractor dealer. On a 20 year old engine I would want to change all rubber parts, meaning belt, impeller and hoses. New oil and oilfilter and it's ready to be fired up. You need to bleed the injectors first, of course, that should be described in the manual. The oil in the cylinders thing I would only do if it does not turn over, but opinions differ about it, some like to know the cylinders are not dry. A few ml of two stroke oil will do it, you only want some oil on the rings after all.
    After it warms up nicely you can run oil detergent trough it. 20 years with the same oil in it is bound to get you some sedimentation. After that another oilchange and all should be fine.

  6. #6
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    Default Re: Installing new Nanni engine

    I'm not sure about the necessity of the oil in the cylinders either but if that's the advice then ...
    Just as a general comment, the single most common boat engine killer I hear about and have heard about all these years is exhaust and engine damage from exhaust water. So just a note/flag on that. Get the water lock capacity right, use all available height, get the back pressure right, which probably means all new and up a size.
    What a score!

  7. #7
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    Default Re: Installing new Nanni engine

    I carried a 16 hp then an 18 hp for 20 years.... then got a 40hp.
    The boat was the same but I got older.
    40 hp good!

  8. #8
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by wizbang 13 View Post
    I carried a 16 hp then an 18 hp for 20 years.... then got a 40hp.
    The boat was the same but I got older.
    40 hp good!
    Im sure in a long-long keeler like Woodwind 40hp is welcome......and you probably displace twice as much, and a lot more top-hamper windage.

  9. #9
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    Default Re: Installing new Nanni engine

    Nice score. Fun project. Keep us posted.

  10. #10
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    Default Re: Installing new Nanni engine

    Most of the time, the 24hp is fine. Pushing into a wind or big current though, it's underpowered. Ideally, I'd have found something around 30 hp but this one came along and I have it now. I'm gathering info re the shaft and prop, as mentioned. But first I want to make sure the engine runs!

  11. #11
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    Default Re: Installing new Nanni engine

    Thanks. Yes, already have a new impeller ready to install and new filters on the way. The matching water lock came with the engine and it's a big `un! Thanks for the tip re type and quantity of oil to drip onto the pistons! The engine's never had any coolant or fuel in it. I'll rig up a gravity feed system for fuel in the shed and bleed the injectors when I'm ready for a trial run.

    A friend installing an old engine, also recently, had the engine over run - destroying the engine and covering everything in the vicinity with soot. Not pleasant. Apparently the only way it can be dealt with is by blocking the air intake so I'll have a plug ready! But I think it can be caused by sticky governors so I'm also wondering if there's a neat way to test that mechanism before I run the engine?

    Rick
    Last edited by RFNK; 03-05-2018 at 07:50 AM.

  12. #12
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    Default Re: Installing new Nanni engine

    Rambling...

    I would be far more worried about the crankshaft and camshaft bearings etc. being lubricated than the pistons/rings.
    To prime an oil system it is not uncommon to interupt the oil filter circuit somehow and "prime" with an external pump. If you can slowly rotate the engine while doing this, "everything" gets lubricated that way.
    I have done this many times, it's good insurance for any engine that has been sitting for an indefinite time. After the oil pump etc. is externally primed, and while the injectors are still removed, you could spin the engine using the starter and check oil pressure. You can also check fuel delivery from the high pressure pump and through the injectors (by connecting them externally) at this time. (This test can also prove fuel shut off)

    *If the engine has never been run, it is a good chance the high pressure pump and the injectors still contain "calibration oil", which does not turn to glue.

    Kubotas are good engines...
    Presumably it was shipped with a volatile corrosion inhibitor additive in the oil and all is fine. Most new engines are.

  13. #13
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    Default Re: Installing new Nanni engine

    As said I am not convinced it is necessary to oil the pistons, but that's your decision. Please use as little as possible if you do it. The engine will start on the oil alone, and if you use to much you run the danger of hydrolock. This is a procedure intended for stuck rings, and that happens in engines that sat to long with valves open in a humid environment. It's unlikely that is your case, somebody knowingly storing an engine usually stuffs intake and exhaust with an oily rag.

    Put a shutoff valve in the fuel line and have a CO2 fire extinguisher ready if you are fearing a runaway. If the unfortunate event happens spray CO2 into the intake and shut off the fuel. Much safer than using some plug.

    This is a new engine even if it sat 20 years. I think you will discover it turns over and runs without any problems.

  14. #14
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    Default Re: Installing new Nanni engine

    Okay, thanks! I'll see if I can work out how to prime the oil system. The engine has been stored indoors but I don't think it had oily rags in either the intake or exhaust. It does now but only since I picked up the engine last year.

    A mechanic told me to keep a block of wood handy to place over the air intake to, effectively, plug it in case of an over run. You don't think that would work?

    So, connect the injectors to a fuel line externally, run the engine with the starter and see if the governor shuts down the fuel as it should. Is that right?

    Rick

  15. #15
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by RFNK View Post

    A mechanic told me to keep a block of wood handy to place over the air intake to, effectively, plug it in case of an over run. You don't think that would work?



    Rick
    Finally ,a use for crocs

  16. #16
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by John B View Post
    Finally ,a use for crocs
    In my friend's case, which included a local, very highly regarded mechanic, they didn't have a block or any other plug handy. The few seconds it took to find something were enough for the engine to stop of its own accord; basically by breaking everything breakable. The engine's a total write off. I'm proud to say I have no crocs.

    Rick

  17. #17
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    Default Re: Installing new Nanni engine

    Speaking from experience, have someone go over the engine and make sure it's operational before you put it in the boat. I put an engine that had been sitting for years in my boat, only to find it needed work. The work is easier and more cheaply done on a bench than in the boat
    Elect a clown expect a circus

  18. #18
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by Bobcat View Post
    Speaking from experience, have someone go over the engine and make sure it's operational before you put it in the boat. I put an engine that had been sitting for years in my boat, only to find it needed work. The work is easier and more cheaply done on a bench than in the boat
    That's the plan!

    Rick

  19. #19
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    Default Re: Installing new Nanni engine

    Oil system priming with homemade preoiler(there are commercial versions of the same thing but with steel tanks): http://www.enginelabs.com/videos/tec...-ls-pre-oiler/ Also functions with an external oil gear pump instead of the tank (turbo oil scavenge pump). You can use the oil pressure sender port with the apropiate fitting instead of drilling a plug.

    Your engine should have glow plugs, no need to take the injectors out. Just remove them, put some oil in with a syringe if you insist, prime the oil system, replace glowplugs, fill in oil and fire up.
    Yes the wood block works if you have a flat surface on the intake. The CO2 extinguisher works regardless of that.
    Don't mess with the injectors, the fuel spray could cut off your finger.

  20. #20
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    Default Re: Installing new Nanni engine

    I don't know the model of the engine in question, but if the engine has glow plugs, do a google search on cracked or failed pre-combustion chambers. And then don't mess with it... I wouldn't add anything to the combustion chambers, it is not necessary.

    (If you can't prove the fuel shut off to the injectors, standing by with CO2 bottle is a very good idea, I once had to shut down a runaway 3306 Cat and it wasn't easy. What ever you do, don't put your hand over the intake!)

  21. #21
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    Default Re: Installing new Nanni engine

    I read an interesting article/ thread some years ago about changing yacht engines . The guy was very experienced and had a lot to say.

    I particularly remember one comment he made . In all the re-power jobs he'd done the engine mountings on newer engines were always higher than the one getting replaced . So it was always just a matter of making packers or blocks, or using larger flex mounts to get the height right.

    A positive thing, had a look at any of that yet?( thinking back to making an MDF motor profile template when I did it. Some cross plates to get the breadth)

  22. #22
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    Default Re: Installing new Nanni engine

    Spoke to the mechanic at Nanni in Sydney today. He agreed with you guys that it's not necessary to put oil on the pistons. He also said he didn't think I'd have any problem with the lubrication generally - just use new oil, change it after a few hours of running, then again at the specified 20 hrs. So I'll do that. Put oil and coolant in today, installed the new impeller, and picked up some hoses ready for the test run, hopefully tomorrow. I'll run the engine without fuel briefly before setting the fuel up. I've already turned it over a bit by hand and all seems okay. I'll have the wood block and the fire extinguisher ready for the real test. No hands!! The Nanni guy suggested running the motor for just a minute then turning it off, doing that again, then, if all okay, run it for about 20 minutes. He also suggested getting a mechanic to check the engine running before I do the install - so I'll do that too.

    JB, I made a rough template when I was considering buying the engine, to check the fit. I plan to make a box template, as you suggest, after I've removed the old engine.

    Thanks again, all! I'd have already removed the injectors if it hadn't been for your warnings!

    Rick

  23. #23
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    Default Re: Installing new Nanni engine

    All good so far. I ran the engine without fuel briefly and all seemed fine - at least once I remembered that you have to turn the ignition on AND push the key in on Nanni panels. So, with the garden hose running into a bucket and a pre-filled hose running from the bucket to the water pump, and a jerry can of fuel sitting up beside the engine and a pre-filled line running to the fuel pump, and the return tube running into a waste bucket, and a bit of PVC pipe running from the exhaust mixer out into the garden, we commenced by purging the fuel system. My old friend David was here to help, and very helpful as always. The engine has a great setup for purging/bleeding the system. There's a thumbwheel to open up a passage so fuel goes straight from the pressure pump to the return tube, and a little manual lever on the fuel pump so you can pump fuel through until most of the air in the system is purged. That took around 10 minutes, i guess. Then we started her up. It was rough, coughed and spluttered a few times while, I guess, a bit of air still passed through and the fuel reached each cylinder, but after just a few false starts, it all settled down and ran, well, beautifully. We ran it for about 10 minutes. Tomorrow, I'll run it for longer to see what temperature it reaches and just to make sure it's all pretty smooth before I pack it all up and commence removal of the old engine. I'm feeling very pleased and relieved that there's no obvious problem but tomorrow will be a better test so fingers and toes are still crossed. But, I have to say, I can hardly believe how smoothly and quietly it seems to run!

    Rick

  24. #24
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    Default

    Excellent!

    Sent from a phone.
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    Paperback E-book

  25. #25
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    Default Re: Installing new Nanni engine

    Thanks for sharing. This is an interesting thread.

  26. #26
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    Default Re: Installing new Nanni engine

    Welcome! Hopefully, as long as today's test runs smoothly, it'll get a bit more interesting. The next step is to commence removal of the Bukh. This will involve cutting out the floor of the cockpit, removal of the central water tank, making up a temporary floor to seal the boat from weather, and then disconnecting the engine. We'll then tow the boat about 10 km to the boatyard at Nelson Bay and have the engine lifted out with their travel lift. Then we'll tow the boat back to the mooring and I'll commence preparations for the new engine. The guy I bought the boat from did a beautiful job restoring Masina's interior but never addressed issues in the engine bay, especially under the engine, so I'm looking forward to getting in there and sorting it out.

    Rick

  27. #27
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    Default Re: Installing new Nanni engine

    I was wondering how you were going to get it out.
    Running it up in the workshop you won't get up to temperature , I'd be surprised if you can get the thermostat open actually.
    I had an overheating event october 16 which prompted me to do 'everything' ,replace 'everything' with the result that I now have a motor that runs cool as a cucumber. I can run it in gear in its berth at scary rpm forever and I can't get it over about 70. It needs proper load and above 2500 to get into the 80's now.
    Incidentally , a great , really great must have toolkit addition is an infrared temperature gun. Fantastic thing , if only to check your gauge calibration.( if you have one)

  28. #28
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    Default Re: Installing new Nanni engine

    Okay, I didn't know how warm it's likely to get. Where do you get an infra-red temperature gun? I know I can look it up, of course!

    Rick

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  30. #30
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    Default Re: Installing new Nanni engine

    Yep, I bought one from repco ,but a friend has that red one and seems happy.

    The best advice I seem to be able to get from canvassing people I trust tells me a marine motor should run in the low to mid 80's. 90 seems a bit hot for running long periods, so I don't let it go there.(I might be a bit conservative there but I'm extending the life of an old motor , not running a new one, so take that as opinion)
    Most thermostats fully open around 82( 3?). If you do remove the thermostat at any time remove the 'bead' and drill out the hole its in up a size. That allows a better progressive warm up to the nether parts of the motor. The little brass tab you can see here.


    A car motor will probably run hotter .
    Last edited by John B; 03-07-2018 at 04:51 PM.

  31. #31
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    Default Re: Installing new Nanni engine

    When re-powering my boat, it was hard to get the engine to temperature without a load. But it all worked out. It runs at 80 degrees C once you're underway and at cruising RPM
    Elect a clown expect a circus

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    Default Re: Installing new Nanni engine

    One should not mess around with thermostats. A motor is designed to operate in a specific temperature range. That's why the correct thermostat specified by the factory is crucial to motor longevity. It's not only about the often cited exhaust emissions or the performance, it's about metal expansion. The components are milled to have the correct clearances at the specified temperatures. The temperature ranges differ with motor conception age and sofistication (simple or electronically controlled, one or two circuits), with a trend towards hotter in more recent motors. The heat exchanger must be properly dimensioned to remove all excess heat at full stated continuous power (for boats that means WOT).

  33. #33
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    Default Re: Installing new Nanni engine

    That thermostat mod is common here. The primary function of the little jiggle valve is to burp or equalise coolant, right?
    The reason many people remove it and drill it out slightly is to allow heated water past to the other side of the thermostat and gently warm that fluid and the engine parts associated with it on start up. Seems logical to me .
    Anyway , that suggestion came from my engine guy plus a few other mechanical sources when I was trouble shooting our problem, so I'm happy with it.
    Our issue in retrospect ,must have been a single event , like a bag trapped over our intake . But it made me gunshy and I did 'everything' from a new thermostat to a new intake through hull up a size , plus the usual heat exchanger/ impeller stuff.

  34. #34
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    Default Re: Installing new Nanni engine

    Glad the new motor runs nicely Rick.

  35. #35
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    Default Re: Installing new Nanni engine

    Thanks. Ran it today for about half an hour and all good. Tenp didn't pass 40. One thing though - no fuel runs out of the return tube. I thought diesels only used about half the fuel and returned remainder to the tank?

    I'm also looking for the anode. Can't find anything in the manual or on the engine - where the blazes is it?

    Rick

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