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Thread: 20hp(ish) marine diesels - anyone recent advances/suggestions?

  1. #51
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    This page could be useful Greg ... https://www.electromaax.com/product-...ked-questions/

    What about the alternator?

    Since the acceptance rate described the maximum rate at which a battery bank can be recharged, it stands to reason that the proper size alternator can only be selected once the acceptance rate has been determined. It is wasted money to charge a battery bank that has an acceptance rate of 70 amps with a 165 amp alternator. Likewise, using a 100 amp alternator to charge a battery bank with an acceptance rate of 240 amps is pointlessly slow and inefficient. The goal is to get the output of your alternator (under actual charging conditions) to match the acceptance rate of your battery bank as closely as possible.
    Most alternator manufacturers will provide you with the output curve of the alternator you are considering under hot conditions and at a variety of speeds. An alternator rated at 150 amps will likely only put out 130 amps once it gets hot and will only do that running at full speed. Under realistic charging conditions, you may only be running your engine at 1100 – 1200 RPMs. If your alternator is belted at a 2 to 1 ratio it will be spinning at twice that speed, or 2200 – 2400 rpms then it is quite possible that 150 amp alternator is now only going to putting out 80 amps or so.
    Given this, how is it possible to get 200 to 300 amps of real charging capability? Sometimes it isn’t possible, but don’t give up too quickly. Very large alternators with outputs of 200+ amps are now quite common. Additionally, it is often very practical to use two or more alternators simultaneously to charge a single bank. Some boats are already set up to have one alternator charge the engine start battery and a second to charge the house bank. Usually the engine start battery needs little if any charging. An automatic battery bank combiner can be used to allow both alternators to charge the house bank.
    '' You ain't gonna learn what you don't want to know. ''
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  2. #52
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Rumars View Post
    You are welcome Larks. I am not trying to steer you one way or another. Shop around, pricing may differ, someone may have a deal on something. If you get a good deal on a Mitsubishi buy it. Fuel consumption will be around 10-20% more, but for this size of engine that is negligible, under 0,5l/hour. And it will probably be quieter and smoother running.

    The 120A alternator is a bonus only if you got the batteries to match. Normally smaller vessels do not, so on smaller engines you find smaller alternators. For example to fully use the 120A alternator you would need at least 300Ah AGM's, or 340Ah gel, or 480Ah flooded lead acid batteries. Anything more than that just takes longer to charge, anything less and you are not using the full 120A because the batteries can not accept them. A 120A at full power will take some 4HP from the engine so that is another reason you don't see big alternators on small engines.
    Thanks mate but can you help me? ( I hope this is OK Greg .... not too much drift ) . If the batteries are charged doesn't the alternator just spin at the load required to maintain them (the batteries), irrespective of the alternator's maximum possible charge rate ? That only being drawn if the batteries will take the charge ?
    '' You ain't gonna learn what you don't want to know. ''
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  3. #53
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by PeterSibley View Post
    This page could be useful Greg ... https://www.electromaax.com/product-...ked-questions/

    What about the alternator?

    Since the acceptance rate described the maximum rate at which a battery bank can be recharged, it stands to reason that the proper size alternator can only be selected once the acceptance rate has been determined. It is wasted money to charge a battery bank that has an acceptance rate of 70 amps with a 165 amp alternator. Likewise, using a 100 amp alternator to charge a battery bank with an acceptance rate of 240 amps is pointlessly slow and inefficient. The goal is to get the output of your alternator (under actual charging conditions) to match the acceptance rate of your battery bank as closely as possible.
    Most alternator manufacturers will provide you with the output curve of the alternator you are considering under hot conditions and at a variety of speeds. An alternator rated at 150 amps will likely only put out 130 amps once it gets hot and will only do that running at full speed. Under realistic charging conditions, you may only be running your engine at 1100 – 1200 RPMs. If your alternator is belted at a 2 to 1 ratio it will be spinning at twice that speed, or 2200 – 2400 rpms then it is quite possible that 150 amp alternator is now only going to putting out 80 amps or so.
    Given this, how is it possible to get 200 to 300 amps of real charging capability? Sometimes it isn’t possible, but don’t give up too quickly. Very large alternators with outputs of 200+ amps are now quite common. Additionally, it is often very practical to use two or more alternators simultaneously to charge a single bank. Some boats are already set up to have one alternator charge the engine start battery and a second to charge the house bank. Usually the engine start battery needs little if any charging. An automatic battery bank combiner can be used to allow both alternators to charge the house bank.
    Thanks Peter, great info’!!!

    Quote Originally Posted by PeterSibley View Post
    Thanks mate but can you help me? ( I hope this is OK Greg .... not too much drift ) . If the batteries are charged doesn't the alternator just spin at the load required to maintain them (the batteries), irrespective of the alternator's maximum possible charge rate ? That only being drawn if the batteries will take the charge ?
    absolutely OK, I’m interested as well. I do have a couple of 12v books at home that I plan to refer to.....at some stage.... I just hadn’t picked them up in anger yet. I have “The 12 volt bible for boats” and another that I can’t remember.....maybe “The 12 volt doctor” or something like that. I should get Kate to post them up to me so that I can read through them and study up.
    Larks

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  4. #54
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by PeterSibley View Post
    Thanks mate but can you help me? ( I hope this is OK Greg .... not too much drift ) . If the batteries are charged doesn't the alternator just spin at the load required to maintain them (the batteries), irrespective of the alternator's maximum possible charge rate ? That only being drawn if the batteries will take the charge ?
    Yes you are correct. However in a boat this situation would only exist if you leave the dock with charged batteries, hand cranking the engine and without any electronics on. Or if you motored a long time without using anything electric, or if you have enough solar. The reason you see large alternators in newer cars is because all of the electronics in it have to be powered. No car has 300Ah batteries but a lot have 100Ah alternators. It's the same for boats. When leaving the dock with full batteries your alternator supplies just enough current to power all of your electronics that are switched on and the power consumed by the starter motor. If you motor long enough the batteries will be full and output would be reduced to what the electronics demand. When returning to dock the alternator is suppling power to the electronics plus replacing all the power they consumed while sailing. As you said the alternator has a duty cycle dependent on rpm and temperature and in a ideal world everything would be matched. In reality we just accept the losses and slap a bigger alternator on hoping to even everything out. Its the same as installing a diesel in a sailboat.
    A diesel motor is stupid for 80% of the sailboats they are installed on, since a diesel loves constant rpm's in a narrow band (around 80% of the power) in order to be efficient. So a diesel makes sense only if you motored long streches at the motors sweet spot. For getting in and out of the dock, short motoring and battery charging a gasoline engine is better but nobody wants the gas inboard anymore so we do not see a nice small fuel injected gas inboard on the market. This results in engine overhaul times that are very low compared to the same engine in industrial use.

    Larks the pricing seems to be similar to here despite our 19% VAT. Craftsman could be lower for another 1500AUD and I predict the Lombardini list price in the same 8000AUD region. People here normally don't buy engines for listed prices they wait for discounts at boat shows so ask the guys directly if they want to give you the discount now or wait until the next boatshow . Once you decided you can work on the boat, the engine can be bought later.

  5. #55
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Rumars View Post
    Yes you are correct. However in a boat this situation would only exist if you leave the dock with charged batteries, hand cranking the engine and without any electronics on. Or if you motored a long time without using anything electric, or if you have enough solar. The reason you see large alternators in newer cars is because all of the electronics in it have to be powered. No car has 300Ah batteries but a lot have 100Ah alternators. It's the same for boats. When leaving the dock with full batteries your alternator supplies just enough current to power all of your electronics that are switched on and the power consumed by the starter motor. If you motor long enough the batteries will be full and output would be reduced to what the electronics demand. When returning to dock the alternator is suppling power to the electronics plus replacing all the power they consumed while sailing. As you said the alternator has a duty cycle dependent on rpm and temperature and in a ideal world everything would be matched. In reality we just accept the losses and slap a bigger alternator on hoping to even everything out. Its the same as installing a diesel in a sailboat.
    A diesel motor is stupid for 80% of the sailboats they are installed on, since a diesel loves constant rpm's in a narrow band (around 80% of the power) in order to be efficient. So a diesel makes sense only if you motored long streches at the motors sweet spot. For getting in and out of the dock, short motoring and battery charging a gasoline engine is better but nobody wants the gas inboard anymore so we do not see a nice small fuel injected gas inboard on the market. This results in engine overhaul times that are very low compared to the same engine in industrial use.

    Larks the pricing seems to be similar to here despite our 19% VAT. Craftsman could be lower for another 1500AUD and I predict the Lombardini list price in the same 8000AUD region. People here normally don't buy engines for listed prices they wait for discounts at boat shows so ask the guys directly if they want to give you the discount now or wait until the next boatshow . Once you decided you can work on the boat, the engine can be bought later.
    Yes, that’s pretty much the plan. I want to settle on the engine so that I can fabricate the engine bed to suit and design and start building the engine box framework and so on outward from there. As far as pricing and discounts, if I go with either the Craftsman or Lombardini I reckon I’ll get as good a discount as would be possible straight up anyway, whether I wait for the boat shows or not - (which are around May). I’ll be really interested to see how the prices compare to your estimates, if they are even close to them I’ll be pretty pleased and it’ll come down to which of the two to choose.
    Larks

    “It’s impossible”, said pride.
    “It’s risky”, said experience.
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  6. #56
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Larks View Post
    Its interesting what you say about Vetus as I had heard similar elsewhere overseas, but the guys here in Oz have always been quite proactive and helpful. I've dealt with them before through work and can't fault their service, so theirs was one of the first engines that I looked at back in 2012.

    I must say that while researching engines again, the Nanni web site is by far the most informative, useable and helpful.
    i do not want to tar all Vetus dealers with the same brush, i think its a more local problem, in that some suppliers here do not answer questions or give information when asked, or in one case called me 6 months after my inquiry. That was a whole lot of money gone back to UK suppliers, must be a Swedish thing, but i mostly import everything marine related now.

  7. #57
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Just an update on current prices (in Oz dollars excluding GST) if anyone is interested. Still waiting on a couple more yet and some have provided me with (supposedly) a trade discount whilst others appear to be standard retail. Interestingly the Yanmar, which was my original ideal but which originally seemed much more expensive than other options, appears to have come down in price and is actually looking like reasonably good value.

    We have our boat show season coming up over the next few months so I reckon there’s still some room to get these prices down a little more:

    Beta 20 (Kubota) 20hp 104kg 75A Alt $7891.00
    Yanmar 3YM20 20hp 110kg 125A Alt $8954.00
    Nanni 3.21 (Kubota) 21hp 106kg 70A Alt $9663.00
    Vetus M3.28 (Mitsubishi) 27hp 134kg 75A Alt $9,337.00
    Vetus M2.18 (Mitsubishi) 16hp 107kg 75A Alt $7,414.00
    Larks

    “It’s impossible”, said pride.
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  8. #58
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Larks View Post

    Universal M3-20dB (20hp 3 cyl) - no price
    .
    I bought a new Universal in 2006.

    It's based on a Kubota 1 liter 3 cylinder.

    $6500 at the time with gearbox and "Admiral" control panel. 300+ lbs for engine and gearbox.

    ran nice and smooth, but they did a poor job "marinizing" it. They basically just took the tractor engine and mated it to the gearbox, then shot paint all over it and called it good.

    All electrical connectors were steel with light chroming.. they didn't even spring for brass. That was very upsetting.

    The paint does not stand up to the salt environment and the injector feedline tubes were getting significantly rusty even though I frequently gunned the whole thing in WD-40.


    I'm not sure any of the brands do any better these days.

    BTW, the Albin AD-2 (made in 1970) is miles better quality, and I wish I had just rebuilt it... 20hp over 500lbs for engine and gearbox.

    100 Cast Iron.. no rust anywhere....

    All electrical fittings brass

    All plumbing... bronze

    Downside is it is a 2 cylinder 1 liter and the vibration is pretty bad.
    Last edited by BrianM; 02-07-2017 at 07:00 PM.

  9. #59
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Greg, some comments that may be of help: beware of the time/cost/eases of installation equation, I bought a pair of what I assumed were Yanmar 3 cyl marine engine engines, with gearboxes, alternators, gauges, etc, at a quite reasonable price, sight unseen from Qld. Turns out they were ride on mower engines, marinised, probably John Deere, with large, heavy cast iron Chinese marine gearboxes (same weight is the engine, maybe more) some reasoable gauges, car alternators. They were good engines, 3TH72 Ithink, 970cc, 3 cyl, about 18HP at 2800RPM. The exhaust manifold looked to made in Australia, water cooled and well made. The heat exchangers were cast iron and heavy.

    What I did was to make a bell housing pattern which I got cast in aluminium and fitted a ZF 10 gearbox, much lighter! Modified the original heavy ss mounts and mounted engine of rubber isolation mounts on heavy wooden bearers. Made up a vinylester glass heat exchanger with a copper tube core, modified the original cooling pump drive (aft facing, engine, too fast) by making a drive with a small section double v belt pulley. Then attached the pump to a bracket that clamped to the drive I made, attached the existing Jabsco pump and made a large double v belt pulley for the pump, the pump now runs at a max of about 900 RPM and is forward facing for easy impeller changes. Found an alternaor with a tacho sender for the tacho. No handstart capability (yet). The engine side of the cooling sysem includes the exhaust manifold, so no danger of it rotting out, and the heatexchanger I made was of sufficient capacity for this. The engine is very smooth and reasonably quiet. Looking back at the amount of work I put into this, its just insane.

    Much better to buy a new marine engine with all the accessories, I would go for the Yanmar 3YM20 only because of parts and familiarity. My only experience with Lombardini engines were aircooled single cylinder diesels used in a fruit picking machine in the Riverland, the maker of the machines had plenty of dead engines lying around. No experience with the marine versions. The only Bukhs that I have seen were heavy, maybe too much for the aft end of a H28. Chasing the lowest price may not be wise, think of your time and maybe having to fix the thing in the future.
    the invisible man........

  10. #60
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Thats a very reasonable price on the Beta, if the Craftsman is not significantly cheaper, i think thats where i would go.

    With regards to the Albin Ad2, parts are starting to get so expensive now that many people are re-powering, rather than fixing a 40 year old motor.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I am also in a motor selection process and find it quite hard to get my hands on valid, dicriminating facts. Also funny to me, that manufacturers delivering purpose build marine engines directly to the market (as eg Yanmar or Lombardini) are not (willing to be?) cheaper than marinizing companies (like Nanni, Vetus, Sole ...) which are adding one more element to the suplliy chain.

    One minor observation: I have found, that only Nanni equips its mixing elbows with a zinc anode, all other doing nothing on this field (right?): Is this important for corrosion prevention?
    Thomas
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I have found from experience it is best to renew the mixing elbow every 10/15 years.
    One might consider that the mixing elbow IS the anode. Trying to save it,(with zincs) may cause weird problems further in the exchanger...like those copper tubes going hinky.
    Like putting bronze plumbing on an engine made with a lot of aluminum,might come back and bite you in the butt.

  13. #63
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    My Yanmar manual tells me to replace all the rubber hoses and the mixing elbow every 2 years.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Would you consider buying a used engine? I regularly see them around here. Frequently some of the boatyards that do a lot of reporter jobs have reconditioned ones at very attractive prices as they effectively get the core for free as part of the job.

    Just an example I recently found: https://newyork.craigslist.org/lgi/bpo/5964850502.html

    we've have a 2 cylinder Yanmar for 19 years now and it has been solid.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    7 years seems to be the elbow/mixer life for me.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Re engine sizing and some comments earlier about what would be suitable for the H28: for anyone who may be interested in how I calculated my engine size requirements - I found in my old files the calc’s that I’d done a few years ago leading me to be looking for 20hp.


    Sh=1.4 x √WL

    Where ‘Sh’ is the max hull speed in knots and ‘WL’ is vessel water line in feet

    S/√WL = 10.65 ÷ 3√D/Shp

    Where ‘S’ is the given speed, ‘D’ is displacement in pounds and ‘Shp’ is the horsepower required to be generated at the shaft (allowing that there will be some loss of hp through the gearbox etc.)



    D = 4 t = 8818lb (estimated - based on haul out weight pre-refit)
    WL = 26’


    Sh=1.4 x √26
    Sh=1.4 X 5.099
    Sh=7.13


    S/√26 = 10.65 ÷ 3√D/Shp
    S/5.099 = 10.65 ÷ 3√8818/Shp
    1.4 = 10.65 ÷ 3√8818/Shp
    3√8818/Shp = 10.65/1.4
    = 7.61
    8818/Shp = 7.613
    = 440
    Shp = 8818/440
    Shp = 20
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by SailAR View Post
    Would you consider buying a used engine? I regularly see them around here. Frequently some of the boatyards that do a lot of reporter jobs have reconditioned ones at very attractive prices as they effectively get the core for free as part of the job.

    Just an example I recently found: https://newyork.craigslist.org/lgi/bpo/5964850502.html

    we've have a 2 cylinder Yanmar for 19 years now and it has been solid.
    No, 'had that discussion here in previous posts - only interested in new for this rebuild.
    Larks

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  18. #68
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Larks - Have you made a decision yet as to which one you'll go with?

    I think I'm about in a similar stage with my project as you are with yours. I just ordered a Beta 25 from the dealer which I plan to install this spring. I had it narrowed down to Beta or Yanmar. They both were similarly priced. In the end, it came down to both the dealer helpfulness and the feedback I got from this forum regarding Beta, which seemed favorable. That, and I can get future parts from any Kubota dealer, which is easy around here.

    I've been figuring out electrical panels too so I've been keeping an eye on your latest threads. Thanks for sharing your project.

    Travis.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I’m still waiting on a couple of prices Travis, including the Lombardini, but at the moment I’m leaning most heavily towards the Yanmar 3YM20. The main dealer/head office for our state is just around the corner from home and the price is looking quite competitive, warranty is the best of the options and parts and service are readily available and seem to be reasonably priced.

    Our boat show season starts in a few weeks so I plan on making my final decision when I get a chance to pin the dealers down on their best price at the first boat show on the Gold Coast.
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Said it before, get a Yanmar and be done with it. Great reputation, guaranteed peace of mind.
    whatever rocks your boat

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    The Nanni looked quite good
    '' You ain't gonna learn what you don't want to know. ''
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I think Beta were offering something like 5 year warrantee and 12 months install grace period, which is something to think about. I found for the model I was looking at though the Nanni was the smallest overall dimensions which seeing as its the same base engine i'm not really sure about, probably something about heat exchanger size???
    Size may not be as crucial for you though.
    Last edited by andrewpatrol; 02-15-2017 at 05:25 PM.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by PeterSibley View Post
    The Nanni looked quite good
    Just had a call from Nanni, their boat show special is VERY competitive and they are offering to include the Waterlock, Strainer, Syphon Breaker, Coupling and delivery to Gold Coast in that price.......that’s worth around another $800.00, going on their previous quote.

    However - even while typing this, the Lombardini/Kohler price has come in and that’s just slightly better again.......


    So it’s become not quite as simple a decision as the “buy the Yanmar and be done with it” solution as it was looking this morning, the Nanni or Kohler/Lombardini are now looking like the best buy....it’s boiling down to:

    Yanmar 3YM20: 21hp, .854ltr disp, 125amp alt, 130kg, 600mm (h) 463mm (w) 693mm (l)
    Nanni 3.21: 21hp, .719ltr disp, 70 amp alt, 106kg, 506mm (h) 462mm (w) 659mm (l) - $30.00 less than the Yanmar - but includes Waterlock, Strainer, Syphon Breaker, Coupling
    Kohler (Lombardini) LDW702: 20hp, .666ltr disp, 120amp alt, 99kg, 522mm (h) 488mm (w) 560mm (l) - $450.00 less than Yanmar


    Edited to add - I misread the Kohler quote which didn’t include 10% GST as the others did, so it’s not quite as good a deal as the Nanni by about $350.00
    Last edited by Larks; 02-15-2017 at 11:47 PM.
    Larks

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  24. #74
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Larks View Post
    Just had a call from Nanni, their boat show special is VERY competitive and they are offering to include the Waterlock, Strainer, Syphon Breaker, Coupling and delivery to Gold Coast in that price.......that’s worth around another $800.00, going on their previous quote.

    However - even while typing this, the Lombardini/Kohler price has come in and that’s just slightly better again.......


    So it’s become not quite as simple a decision as the “buy the Yanmar and be done with it” solution as it was looking this morning, the Nanni or Kohler/Lombardini are now looking like the best buy....it’s boiling down to:

    Yanmar 3YM20: 21hp, .854ltr disp, 125amp alt, 130kg, 600mm (h) 463mm (w) 693mm (l)
    Nanni 3.21: 21hp, .719ltr disp, 70 amp alt, 106kg, 506mm (h) 462mm (w) 659mm (l) - $30.00 less than the Yanmar - but includes Waterlock, Strainer, Syphon Breaker, Coupling
    Kohler (Lombardini) LDW702: 20hp, .666ltr disp, 120amp alt, 99kg, 522mm (h) 488mm (w) 560mm (l) - $450.00 less than Yanmar


    Edited to add - I misread the Kohler quote which didn’t include 10% GST as the others did, so it’s not quite as good a deal as the Nanni by about $350.00
    Looking at all the numbers except price, the yanmar is the least stressed on a CC to hp basis, and has 31kg more nuggetyness (yes, that is a real word ;-) ) than the Kohler.
    Is that a cast iron block and head vs alloy, or just all round more solid working parts?

    Pete
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Posted this on your other thread Larks. Jay

    The engine in "Bright Star" was Universal Atomic 5416 twin diesel that produced 16hp and weighed in at 365lbs/165.5kg. I have always wished the engine were lighter in weight. It was installed in the 1960's and gave good service but, even though it had a heat exchanger, it gave up to a perforated water jacket and was unreparable. We considered the Yanmar but, I still want less weight in the stern. It looks like the Kohler/Lombardi will be the one I will take. It produces 18HP, two more HP than the old engine and it weighs in at 99kg/218lbs which is 147lbs lighter than the old engine. That makes an amazing difference to my thinking!
    Thanks for the reference to the Kohler/Lambardini Diesel Larks! Jay

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by epoxyboy View Post
    Looking at all the numbers except price, the yanmar is the least stressed on a CC to hp basis, and has 31kg more nuggetyness (yes, that is a real word ;-) ) than the Kohler.
    Is that a cast iron block and head vs alloy, or just all round more solid working parts?

    Pete
    There’s an extra cylinder in there Pete, not sure that it’d add up to the extra 31kg, but it’d help - however that theory contradicts why the 3 cylinder Nanni is only 7kg heavier than the Kohler and 24kg lighter than the Yanmar.

    The Kohler 702 does have (if I’m reading between the lines correctly) a cast iron cylinder head and block (the smaller 502 has an aluminium block).

    But it also has an overhead camshaft and one reviewer elsewhere seemed to think that this is an issue on a boat - however I can’t think why.....any thoughts on that?
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    OHC's tend to be taller, so they don't fit in small spaces as well. Also, timing belts may need maintenance. A snapped cam belt = new engine.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    My Lombardini 903M was junk after 1500 hours. I had to replace the heat exchanger at around 1000 hours, also changed glow plugs, wiring harness, feed pump and alternator. The panel also is u/s.
    I am currently installing a Beta 20. The boat is Gartside 116, 10500 lbs. The old engine had too much power so 20 hp should be about right. As per the recommended 3-4 hp pr.ton.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by robm View Post
    OHC's tend to be taller, so they don't fit in small spaces as well. Also, timing belts may need maintenance. A snapped cam belt = new engine.
    Thanks Rob, I suppose I don’t consider maintaining a cam belt as such an issue as others might, having replaced a few on other engines and cars - the Kohler shows them as a 4000 hour replacement and they look to be easy access and a relatively simple job to replace, compared to many others that I’ve had to do.

    Height wise, it is 522mm, the Nanni 506mm and the Yanmar 600mm.





    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I had some experience with a Nanni using an overhead camshaft, and the toothed belt and pulleys were not what I consider "marine grade" only a dust cover on the belt and the toothed pulleys were seriously rusted. Broken belts were common.
    A non-overhead gear driven cam is largely bullet proof.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    A pushrod engine will probably have a decompression mechanism that will be simple. not sure the same could be said of OHC. I would make sure whatever engine you have has decompression lever/levers. May give you a starting capability with a weak battery and the ability to clear the engine of water ingestion OHC is another thing to worry about, pushrod is the go here. Wouldn't have a diesel engine with an alloy head, unless an aircooled Lister. Reliability/ease of servicing at a reasonable weight/horsepower should be the criteria. Hand start is a bonus.

    Some of the other things I've done is to keep the saltwater cooling injection well away from any ferrous metals or aluminium. Make sure the flex mounts are soft. I will be attaching a flex mount to the top of the engine to hold the engine if the boat ends up laying over.
    the invisible man........

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Seconded on the decompression lever but I don't like the chances of finding on on a modern engine. As Adrian says , you can start an engine with an essentially flat battery with one. A hand start is another old fashioned but desirable feature .... the two go together I guess.
    '' You ain't gonna learn what you don't want to know. ''
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Have you investigated Farymann engines? I certainly like our 23 hp 2-cylinder.

    http://www.farymann.com/engines.php?page=18wMarine

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Paul G. View Post
    Said it before, get a Yanmar and be done with it. Great reputation, guaranteed peace of mind.
    On reflection, and after discussing this subject with a few people recently( now a repower is on our hopefully somewhat distant horizon), I think this is what we would look at. And resale is good with yanmar in the boat.
    Regarding decompression on a modern light motor, I don't think you'll get it. You have to rely on the starter motor. But with solar and those small jumpstart batteries you can cover most issues these days. I have a dilemma for example, should I buy a starter motor to carry as a spare for that reason....
    Even that isn't as bad as it could be , they can be bought as aftermarket now and not too expensive. The reality is that unless you hydro lock the motor you'll probably never need to worry about it.
    Last edited by John B; 02-17-2017 at 03:09 PM.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Thanks for the PM JB.

    I had fixed my sights on the Yanmar when I first went through the exercise five years ago, but at that time it was the most expensive of options so, while I’m keeping a tight rein on the rebuild budget, I’ve been much more influenced by price this time around. But as the Yanmar seems to have come down slightly in price and the others have gone up slightly, the margin no longer justifies the compromise of going to another option. If I can still pick up the Yanmar at the Hobart boat show special price of $9k (or less), the weight (an extra 30kg) seems to be the Yammer’s only remaining vice.

    I’m not overly worried about the decompression lever, having had to start an 82hp Perkins at sea with a makeshift pull cord I’m very mindful of battery management and alternative means of starting an engine.
    Larks

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  36. #86
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Dave Hadfield View Post
    Have you investigated Farymann engines? I certainly like our 23 hp 2-cylinder.

    http://www.farymann.com/engines.php?page=18wMarine
    I hadn’t heard of them Dave, but I see that the rep’ in Australia is a guy who I know and who is also in my neighbourhood, though it doesn’t look like he may have the same range available here in Oz as you do in the US. But, as much as I’m now pretty much convinced that I’ll go with the Yanmar, I’ll check them out next week when I’m back home and see what he has and how they might compare price wise etc.
    Larks

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  37. #87
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Larks View Post
    Thanks for the PM JB.

    I had fixed my sights on the Yanmar when I first went through the exercise five years ago, but at that time it was the most expensive of options so, while I’m keeping a tight rein on the rebuild budget, I’ve been much more influenced by price this time around. But as the Yanmar seems to have come down slightly in price and the others have gone up slightly, the margin no longer justifies the compromise of going to another option. If I can still pick up the Yanmar at the Hobart boat show special price of $9k (or less), the weight (an extra 30kg) seems to be the Yammer’s only remaining vice.

    I’m not overly worried about the decompression lever, having had to start an 82hp Perkins at sea with a makeshift pull cord I’m very mindful of battery management and alternative means of starting an engine.
    I think you've talked about the pull cord before, but I don't remember the details.
    When we first had Waione she had a Ford 1500cc petrol motor in her. It was fine but we fell into that neverending failing peripherals issue.. electrics, fuel pump, water pumps etc. I had to crank start it but didn't have a crank, so used a ratchet on an extension and socket straight onto the crankshaft pulley. There was a zen thing to it, else it bit you.

  38. #88
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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I have a 55 hp Lees marine Ford D series that just seems to keep going even though I was advised would need replacing when the boat was purchased 10 years ago.
    I do have 2 Bosch 700 CCA batteries on it though.
    It starts OK with one, but prefers 2!
    Whatever I get as replacement will be smaller, lighter, quieter, less smelly and start with only one battery.
    It stopped in the middle of the rip in Cook Strait last month coming back from Nelson.
    We were still doing 5 knots with the current, so I changed the prefilter from the tank once we got into flat water and carried on.
    I must remember to buy some diesel bug treatment snake oil when it back in stock.

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Larks there is a great fully rebuilt Yanmar 20HP for sale here that you could probably get for nz$6k if value for money is high on the list I think the link for it is on the other page. Something else to consider is that you don't really need a huge amount of redundancy on your boat because its got sails and eventually the wind will blow you in the right direction i.e. handstarting is nice but with an averagely well maintained engine you should never need it. Uunless you plan to keep the boat for a long time then perhaps a good second hand motor is all you need.
    whatever rocks your boat

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Paul G. View Post
    Larks there is a great fully rebuilt Yanmar 20HP for sale here that you could probably get for nz$6k if value for money is high on the list I think the link for it is on the other page. Something else to consider is that you don't really need a huge amount of redundancy on your boat because its got sails and eventually the wind will blow you in the right direction i.e. handstarting is nice but with an averagely well maintained engine you should never need it. Uunless you plan to keep the boat for a long time then perhaps a good second hand motor is all you need.

    Thanks for the heads up Paul, but as I’ve said a few times here before, second hand isn’t a consideration in this case. Value and budget are certainly high on the list, but not at the cost of compromising the integrity of what I want to achieve.
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Larks, plenty of people buy boats with existing motors in other words second hand, and do just fine for their entire ownership. In my case I use my boat a lot and when it was on a mooring I would motor about 1.5 hrs per week for about 40 weeks, on the annual cruise and overnighters add in another 40 hours (which is a lot btw) so about 100 hours a year.

    Thats a lot of hours and now I'm on a marina I would halve that usage, but lets say you do 100 hours on average which really is getting up there for a small yacht. Most small diesels do about 2-2500 hours between overhauls, and some a lot longer if well looked after. I am not trying to make you buy an old motor but a fully rebuilt diesel with freshwater cooling will see out your ownership and them some. What I dont understand from your original question is what you are looking for that any new diesel will not provide.

    On the net most of the engine info and feedback on forums tend to be from those who have had issues and are looking for help, seriously for an H-28 there is no "wrong" new small diesel. I like Yanmar, but Volvo or any Kubota version is just as good, pick a colour and bargain hard. On another note you could get away with a less than 20hp and not really notice a difference, 15 or at a push 10 would still work.
    whatever rocks your boat

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Paul G. View Post
    Larks, plenty of people buy boats with existing motors in other words second hand, and do just fine for their entire ownership. In my case I use my boat a lot and when it was on a mooring I would motor about 1.5 hrs per week for about 40 weeks, on the annual cruise and overnighters add in another 40 hours (which is a lot btw) so about 100 hours a year.

    Thats a lot of hours and now I'm on a marina I would halve that usage, but lets say you do 100 hours on average which really is getting up there for a small yacht. Most small diesels do about 2-2500 hours between overhauls, and some a lot longer if well looked after. I am not trying to make you buy an old motor but a fully rebuilt diesel with freshwater cooling will see out your ownership and them some. What I dont understand from your original question is what you are looking for that any new diesel will not provide.

    On the net most of the engine info and feedback on forums tend to be from those who have had issues and are looking for help, seriously for an H-28 there is no "wrong" new small diesel. I like Yanmar, but Volvo or any Kubota version is just as good, pick a colour and bargain hard. On another note you could get away with a less than 20hp and not really notice a difference, 15 or at a push 10 would still work.
    As I had said, I was looking to hear if anyone was aware of any new products on the market since I last looked at this in 2012 and put together a spreadsheet on what I could find available and costings, as well as what sort of experiences people may have had with their new engines or issues, rumours etc and any advice, warnings or recommendations .

    When I last did this exercise I was managing a marine engineering company and was dealing daily with new and used diesel engines from 2 to 3000hp so had pretty good contact with suppliers and service agencies and so was reasonably up on what products were like and what was available, worth considering and worth avoiding. (And, not wanting to sound unappreciative of your advice Paul, but because of my job I reckon it’s fair to say that I am probably as well, if not more aware than most, of what you can get - or more specifically not get - with supposedly fully rebuilt engines...., even with OEM W6’d engines that have been operated and serviced to OEM recommendations throughout life.)

    But in the last five years or so I’ve been working more with just the bigger commercial engines so have lost touch with what’s happening in that smaller leisure market.

    I have found out from this thread and a few other enquires and contacts that there are indeed some new products on the market here in Oz and I’ve also found that some of those products that were reasonably recent to the Australian leisure market (when I last did this exercise) have had a bit more time in circulation and so there’s more information on their performance....or otherwise.

    There’s at least one brand of engine that I was quite interested in but which I’ve heard sufficient concerns about to temper that interest.

    So this exercise has definitely been well worthwhile for me and I hope, perhaps, for others who may have been taking notice of responses and suggestions.
    Last edited by Larks; 02-19-2017 at 06:31 PM.
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    I've been looking at this also... and honestly, I would have expected that a small efficient gas powered water jet type setup would have picked up in general use. Also, the big bonus in my mind is, when building, no need to put shaft holes thru your keel

    Curious about this approach, if anyone has tried it

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Quote Originally Posted by Dirc View Post
    I've been looking at this also... and honestly, I would have expected that a small efficient gas powered water jet type setup would have picked up in general use. Also, the big bonus in my mind is, when building, no need to put shaft holes thru your keel

    Curious about this approach, if anyone has tried it
    Interesting concept Dirc. When you say gas, do you mean petrol or LPG - liquid petroleum gas? Either way, neither are ideal on boats, but we do have diesel powered marine jets here and I’ve worked with them in the commercial marine industry.

    But thinking of the ones that I know, I can’t say that I can really see much advantage of one on a sail boat over a propellor: They do away with a rudder, but you need that when sailing so there’s no gain there; they’re not particularly fuel efficient; they are more costly to buy and set up; because you have both an engine and a jet unit they are heavier and they add a further complication to maintenance and repair.
    Larks

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    Default Re: 20hp(ish) marine diesels - anyone recent advances/suggestions?

    Larks you should buy the motor you feel confortable with. Any of the listed options is equally good in my opinion, but your peace of mind is the decisive factor. The tehnical solutions chosen by the factory are secondary.

    As for refurbished motors it depends on the standard. A real "exchange motor" refurbished by the manufacturer or reputable shop should be identical to a new one. Waterpump, oilpump, injection pump, turbo should all be new. Often the auxilliaries like starter and alternator are also new, or at least refurbished with new bearings, brushes, etc. On a marine engine I would also expect a new heat exchanger, mixing ellbow and raw water pump. Such exchange engines are common for trucks and buses and come with at least 1 year warranty. Given the mileage they can achieve within a year with a 3 driver team no serious company is willing to risk its good name with shoddy work. After all they expect the customer again.
    But I agree that there also are a lot of vendors offering less quality work and I would not buy form someone whitout a good reputation. And buying from someone who is not in the business of refurbishing engines and where you can not see the machine shop is playing the lottery. I would sooner buy an old engine for nothing fully expecting to refurbish it in the shop of my choice or buy a new popular industrial engine and marinize it myself with a kit.

    I think that most sailboats are actually better served with a petrol engine but I am not aware of a small modern fuel injected petrol inboard for sailboats. They only seem to exist for skijets or as outboards and are to powerfull for small sailboats. I would love an inboard option of an E-Tec for example.

    I have seen LPG conversions in ski towing boats where the operator invested in the needed infrastructure to fuel the boats. Otherwise it's not really practical as floating LPG stations are almost unheard of.

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