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Thread: Installing new Nanni engine

  1. #71
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    Default Re: Installing new Nanni engine

    Gearbox ratio might be the same, but i expect the torque curve is completely different. There is online prop calcs, but it does help to know what size diameter you can swing with the correct amount of clearance. Its in the book.

  2. #72
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    Default Re: Installing new Nanni engine


  3. #73
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    Default Re: Installing new Nanni engine

    As the engine/gearbox exists then the variable is the propeller, as for rotation, some gearboxes will run forward reverse equally, others cannot be run in reverse for long periods, this may need to be known before using an existing propeller.
    the invisible man........

  4. #74
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    Default Re: Installing new Nanni engine

    Having used the boat for years and cleaned the prop so many times, any reasonable person would expect that I'd know which way the prop spins .... but I don't! But I will have a look - tomorrow or the next day, and all will be revealed!

    Rick

  5. #75
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    Default Re: Installing new Nanni engine

    I've cut the bottom out of the cockpit and put a dam of a rubber strip around the hole. I've made up a cover from plywood and fastened that down with screws that can easily be removed. I have to do a boat delivery tomorrow but on Thursday I should be able to remove a waterctank that sits over the gearbox and shaft and then commence removing the old engine. I'll try to remember to take some photos!

    I need 60mm ID hose for the exhaust. The industrial hose place only had 63mm so I bought that. But it seems too loose so I'm wondering if I can pack the exhaust elbow with fibreglass cloth or something for a tighter fit. Any problem with that or better ideas? I do feel a bit of an idiot for proceeding to buy the wring size!

    Rick

  6. #76
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    Default Re: Installing new Nanni engine

    Great thread Rick. Thanks for posting and looking forward to your photos. I'm learning a lot along the way.

  7. #77
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    Default Re: Installing new Nanni engine

    It'll probably clamp down that far. If not glass a bandage on. it doesn't get very hot but the auto parts places sell a heat reactive bandage which post cures and is designed to get hot. Hot air gun if you don't want it to stay sticky.

    On reflection, I would want a packer fully catalytised so it didn't glue to the hose ,for removal.
    Last edited by John B; 03-13-2018 at 11:07 AM.

  8. #78
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    Default Re: Installing new Nanni engine

    I think you have to go a marine place and get proper exhaust hose at about $100 per metre.

  9. #79
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    Default Re: Installing new Nanni engine

    Oh, and having only had half of m first coffee for the day, as the dawn makes a feeble attempt to dispose of the night, I read your last couple of posts only half conscious. I saw you were going to check the prop rotation ASAP. Next thing you are cutting a hole in the cockpit, and I'm guessing just going to keep on going right down until you can see the prop in the water. That sure beats JB just changing a seacock in the water! Kinda glad that water tank got in the way. Need more cofefke.

  10. #80
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    Default Re: Installing new Nanni engine

    I usually go for the soft option, crank the engine and observe the shaft rotation inside the boat , but I could see how jumping in the water could be more fun.
    Most hose retailers won't take cut hose back and chucking a few hundred dollars away is not something I would enjoy. I don't see its much of an issue.
    Did you think of tenting the cockpit for some work space , Rick? Too windy on the mooring?
    Last edited by John B; 03-13-2018 at 08:16 PM. Reason: spooling

  11. #81
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    Default Re: Installing new Nanni engine

    Phil's right. I did say that. I hate that. I forgot to check the prop but I'll try tomorrow.

    It's proper exhaust hose - just that little bit too big. It might clamp down okay. Yes, I have a tarp/tent over the cockpit. For shade, mainly.

    Rick

  12. #82
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    Default Re: Installing new Nanni engine

    You might try a strap clamp, with the nut and bolt for tightening, more power than hose clamp, problem is that you are also trying to compress the wire reinforcing.
    the invisible man........

  13. #83
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    Default Re: Installing new Nanni engine

    Yes, they're the clamps I bought with the hose but they're a little big too. I'll try the next size down from those I have before I try anything else.

    Rick

  14. #84
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    Default Re: Installing new Nanni engine

    Sorry but I don't think you can safely squeeze a thick exhaust hose that much. If you really hate to buy new hose (that would be my advice) have a connecting piece made out of 316 stainless tube. Any good muffler shop shoud be able to make it (also have a spare made), they just have to expand a piece of scrap tubing. Or just find a piece of 60mm ID tube with 1.5mm thick wall (or thicker and turn/sand it down). You will need to cut a slot in the tube (to compress it) and fasten it to the exhaust elbow with a 316 stainless or hot dipped galvanizedU bolt clamp (muffler clamp).
    Last edited by Rumars; 03-14-2018 at 07:27 PM. Reason: Corected the wall thickness, 60mm ID +1.5mm on either side makes 63mmOD

  15. #85
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    Default Re: Installing new Nanni engine

    It's only 1.5mm all round. I tried it today with a smaller hose clamp, the simple, lighter type, and it seems okay. The more robust clamps with bolts that I have are too big. I'll get the next size down of those. I'm pretty sure it'll be okay.

    On a brighter note, I checked the prop today and it goes around the same way as the new motor's gearbox. So, if the pitch can be varied, which I'm yet to find out, I shouldn't need a new prop.

    I disconnected the shaft, all hoses and cabling from the engine today, and disconnected the engine mounts. Tomorrow we'll lift the engine up to cockpit floor level and I'll label and remove all wiring. I want the old engine to be reconditionable by whoever wants it. I also want to remove the flywheel and possibly the gearbox to lighten the engine for lifting at our local wharf. I'm propping up the boom and will use a chain block to lift the engine. There will be photos.

    Rick

    Rick

  16. #86
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    Default Re: Installing new Nanni engine

    Be very carefull with the flywheel, they can be a real ar*e to remove, may need heat and wedges, but be very carefull to restrict its freedom of movement should it fall of its shaft. You might be lucky and it removes without too much bother. Gearbox is more simple and easier to manage! Check your safe working load on any of the blocks involved in any hoisting of that flywheel!

  17. #87
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    Default Re: Installing new Nanni engine

    Thanks! Yes, the Allen bolts are very tight and if they're just too tight I won't persevere. Thanks for the tip re lifting!

    Rick

  18. #88
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    Default Re: Installing new Nanni engine

    The Volvo folding prop is right up there for efficiency ( That's what it is I think). They can be repitched but its such a black art. Often the prop people get it wrong when presented with an unusual boat. Iorangi has a new one on repower and it needed to be bent to get it right , not an unusual story.
    Masina isn't your common type and will be much easier to drive than the 36 ft Beneteau they might have in the computer.
    I'd bet that she will easily reach full revs with the existing propeller ,and if you're going to a different ratio ( eg 2:1 V 2.6:1 say) you might be lucky.
    Anyway , I would be working out the prop rpm to see if was within an acceptable but fairly wide parameter . If so , leaving it alone until the engine was running and fine tuning the pitch last.
    Thats the whole reason I've always bought adjustable pitch propellers over the years. ( Seahawk> Kiwiprop> maxprop.)

    The type strap clamp we can get here are really robust ,a pleasure, a nice thing to fit and well worth it considering the likelyhood of removal for the 5 year ( thereabouts) elbow change . But they have a really fine threshold of adjustment so they have to be bang on for the hose diameter as you're discovering.
    Last edited by John B; 03-15-2018 at 04:31 PM.

  19. #89
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    Default Re: Installing new Nanni engine

    1.5mm is still a decent amount for the hose clamp to take up. I'd be watching it for leakage - though I'm glad to hear you're going with the bolt type - much more rugged.

    On my boat I replaced a 4-107 with a more powerful (& far, far quieter) Yanmar 4JH3E. The prop that was on it was already over-propped & more so with the new higher speed engine. Yanmar wants a cruising RPM of 3300-3500 RPM & with this prop it's more like 2400. I worried about building up carbon, but in 250 hours have little to none. The thing I like is that it pushes a 52' x 12.5' boat at 7.5 knots at the 2400 & I burn about 1/2 gal. per hour. 3K rpm gets me to 8.5-8.7 knots, but burns about 1.25 gal per hour. I had another prop that was under-pitched a bit from the experts' recommendation & it got 7.5 @ 3200RPM - but at about 1.5 gal. per hour. The "over-pitched" prop went back on very quickly!

    As you said - prop specs are a black art...
    "If it ain't broke, you're not trying." - Red Green

  20. #90
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    Default Re: Installing new Nanni engine

    Rick, the pitch of a propeller has to goemetrically match (with a slip factor which will surprise you with the percentage, that book will give you this) the prop shaft RPM and hull speed of the vessel. Fixed pitch props can have a pitch change put in but not much. So now the theoretical prop has the right pitch, how much power can it absorb? Assuming the existing prop worked well and absorbed 24hp, now you want it to absorb 40hp. It may need either be bigger diameter/more blade area/more blades or combo of these. There is a relationship between hull speed/length and available horsepower, too little is easy, you dont get hull speed. Too much is tricky, because to absorb all the power of the engine, the prop may not fit the boat and even if it does, the boat will try and exceed its hull speed. 40 hp sounds ok for your boat and will give some reserve for adverse conditions. Just cautioning you that it may be more complicated than just increasing the pitch. This may work to keep the engine RPM down to safe limits but will reduce efficiency (the angle of attack is too high) and may lead to cavitation which will damage the prop.
    the invisible man........

  21. #91
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    Default Re: Installing new Nanni engine

    I've ordered the smaller clamps. The hose plays does mining equipment, trawlers etc. and they reckon it'll be fine. I'm taking the water trap and hose in when I pick up the clamps so they can check it out. It has the same size spout as the engine.

    Prop sorting out is a bit down the track yet but I will see how it goes before making any changes.

    Engine out today, well, now in the cockpit anyway. Flywheel off and brought home. It wasn't too difficult and not as heavy as I expected. I'll take the gearbox off tomorrow and bring that home. Then I think two of us will be able to lower the engine into a big dinghy. We'll see!

    Bukh out 1.jpg


    Bukh out 2.jpg


    Bukh out 3.jpg

    Rick

  22. #92
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    Default Re: Installing new Nanni engine

    Good job!

  23. #93
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    Default Re: Installing new Nanni engine

    You must get bloody big rain drops over there. That tarp would be useless here.

  24. #94
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by Garret View Post
    1.5mm is still a decent amount for the hose clamp to take up. I'd be watching it for leakage - though I'm glad to hear you're going with the bolt type - much more rugged.

    On my boat I replaced a 4-107 with a more powerful (& far, far quieter) Yanmar 4JH3E. The prop that was on it was already over-propped & more so with the new higher speed engine. Yanmar wants a cruising RPM of 3300-3500 RPM & with this prop it's more like 2400. I worried about building up carbon, but in 250 hours have little to none. The thing I like is that it pushes a 52' x 12.5' boat at 7.5 knots at the 2400 & I burn about 1/2 gal. per hour. 3K rpm gets me to 8.5-8.7 knots, but burns about 1.25 gal per hour. I had another prop that was under-pitched a bit from the experts' recommendation & it got 7.5 @ 3200RPM - but at about 1.5 gal. per hour. The "over-pitched" prop went back on very quickly!

    As you said - prop specs are a black art...
    I think I have the same Yanmar, unless maybe mine is HE? 110hp turbo, pushing a 20 tonne 50 foot boat. I've had her at 11 knots flat out, but I like to cruise at a stately 1800 or so revs, which I know is too slow. Lovely motor. I do open it up every now and again but 3000 feels uncomfortable to me. I have a fancy Hundested controllable pitch prop which allows me to reduce the pitch as the prop and hull get dirty.

  25. #95
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    Default Re: Installing new Nanni engine

    Great progress. Is the shaft offset to port

  26. #96
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    Default Re: Installing new Nanni engine

    Yes, it is.

    Thanks!

    Rick

  27. #97
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by Phil Y View Post
    I think I have the same Yanmar, unless maybe mine is HE? 110hp turbo, pushing a 20 tonne 50 foot boat. I've had her at 11 knots flat out, but I like to cruise at a stately 1800 or so revs, which I know is too slow. Lovely motor. I do open it up every now and again but 3000 feels uncomfortable to me. I have a fancy Hundested controllable pitch prop which allows me to reduce the pitch as the prop and hull get dirty.
    Mine's non-turbo & 53 HP. A friend has the 4JH3TE - which is the turbo version of mine & it's about 75HP. Virtually everyone told me I needed the turbo version for my boat & I ignored them (& am glad I did). I've seen 9 knots with it - but don't need the extra know for the fuel it burns. Mine too is 20 tons - along with 8'3" draft.

    Anyway - enough thread drift. Great progress on the engine & good to see that the flywheel wasn't too bad to remove.
    "If it ain't broke, you're not trying." - Red Green

  28. #98
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by Phil Y View Post
    You must get bloody big rain drops over there. That tarp would be useless here.
    Probably mosquito netting from Maine

  29. #99
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    Default Re: Installing new Nanni engine

    Swallow season and, of all the boats moored near us, it's ours that they love. The netting at least stops the cockpit from resembling the bottom of a bird cage.

    Today I'll remove the gearbox and then start removing the engine control panel and wiring. Masina's engine control panel is in a hatch at the front of the cockpit. It has a waterproof cover so not as vulnerable as it might otherwise be but I find it an uncomfortable location as it's too low and set in too far for easy viewing. The problem is where else to locate it? The bulkhead above the bridgedeck is the obvious location but has its own complications. I also need to find a good spot for a chartplotter and depth sounder. Changing the engine gives me a chance to reconfigure wiring, instruments etc. ..... The thighbone connected to the kneebone, sort of thing ......

    Rick
    Last edited by RFNK; 03-16-2018 at 04:02 PM.

  30. #100
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    Default Re: Installing new Nanni engine

    Maine Mosquitos are about the same size as Swallows

  31. #101
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    Default Re: Installing new Nanni engine

    Erk! We get sandflies, otherwise known as midges, but, fortunately, not right where we live or where the boat is moored. They're so tiny you can barely see them but they attack in droves and leave horrible, itchy welts. We get marsh flies, also called horse flies, that are big, armour-plated and have an amazing way of knowing to attack when your hands are full - especially when your hands are covered in epoxy.

    I left a hatch into the lazarette open once on our Folkboat, to air it out. I didn't go to the boat for a couple of weeks and when I returned, swallows had made a mud nest in the lazarette. I had to run the engine so off we went, baby swallows or eggs (not sure which) and parents, uncles and aunties, flying along behind us. When back at the mooring, they were circling us and as I rowed in,
    they all went straight into the lazarette. It left a mess but the swallows come here to eat the midges and they're beautiful ...... Doesn't really take long to clean up after them but these days I fill any cavities that might be attractive for nesting and I net over the areas that are harder to clean up. After March they go, then we're okay til about January.

    Rick

  32. #102
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    Default Re: Installing new Nanni engine

    Quote Originally Posted by RFNK View Post
    Swallow season and, of all the boats moored near us, it's ours that they love. The netting at least stops the cockpit from resembling the bottom of a bird cage.

    Today I'll remove the gearbox and then start removing the engine control panel and wiring. Masina's engine control panel is in a hatch at the front of the cockpit. It has a waterproof cover so not as vulnerable as it might otherwise be but I find it an uncomfortable location as it's too low and set in too far for easy viewing. The problem is where else to locate it? The bulkhead above the bridgedeck is the obvious location but has its own complications. I also need to find a good spot for a chartplotter and depth sounder. Changing the engine gives me a chance to reconfigure wiring, instruments etc. ..... The thighbone connected to the kneebone, sort of thing ......

    Rick
    You can probably Bluetooth it to your Fitbit watch.

  33. #103
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    Default Re: Installing new Nanni engine

    Right, that way I can also check my heart rate after each gust too.

    Maybe one day I'll work out why anyone would want a Fitbit ..... I'm wildly guessing you don't have one either.

    Rick

  34. #104
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    Default Re: Installing new Nanni engine

    You could do everything on a swing out board. Engine controls on the bottom, plotter and depthsounder above. Ideally I would want a bracket capable of positioning the whole thing out of the companionway to one side over the cabintop under the dodger. Haven't found such a bracket yet, but living with a swinging hatchboard wasn't so bad.

  35. #105
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    Default Re: Installing new Nanni engine

    I've been considering that for quite a while. I saw a hinged setup at a boat show a year or so ago that might do it. I was thinking I'd have to have it swing into the companionway though; I hadn't thought of swinging it all the way around. Hmmmm ... Thanks!

    The bulkhead might yet be an option but it'd be nice to avoid cutting into it.

    I removed the gearbox from the Bukh today and removed all the engine wiring and gauge panel. Hopefully tomorrow we'll get the engine out of the cockpit and into the neighbour's big dinghy, and then I'll be able to start cleaning out and repairing the engine bay.

    Rick

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