Re-power recommendations

Discussion in 'Diesel Engines' started by Brian@BNE, Sep 27, 2012.

  1. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    I have a 50 ft Ocean Alexander with a pair of Cummins 555, 9.1 litre V8's.

    At present we are installing stabilisers, a project that is going smoothly. I could post some pics if anyone is interested. But we have just discovered that the lateral fuel tanks are weeping, and on cleaning they started to leak significantly. So, they have to be replaced. Although they could come out of the sides of the hull, I think we will remove the engines to do it.

    With the engines out, it would be possible and prudent to remove & replace hoses on them, recondition starter motor etc. But very easy to spend a lot of money, and at the end of the day still have 30 year old motors. They have <2000 hours on them, start instantly, hardly any cranking required. And they run smoothly, engine and coolant analyses are good. But they give 270HP each, which is way more than I use. Taking them up to 2900 rpm (rated 3000rpm) they drink 17 gph each which is a bit scary for me, and if I don't have a full load of fuel and water etc I can get 16 knots. So instead I run at half that speed and use <1/4 of the fuel. An obvious thing to do.

    To run at 10 kn, 'high speed cruise' for me I'm likely absorbing around 200HP (combined), perhaps a bit less. Some of these boats had Lemans - not sure whether 120 or 135 - but they were generally regarded as underpowered.

    I don't have any power/propeller curves so my 200HP figure is just an estimate. I figure that re-powering with 2 x 200HP engines would give adequate reserve power for adverse conditions, wind-age etc. Is this thinking about right? Its possible that 2 x 150 would be enough, but I think that would be the lower limit. If so, what are the smart choices for engines? What I really want is to just sip fuel around the 7-8 kn speed, and be loading the engines enough to have them at efficient operating temperature. With my 555's I have to give them a squirt every now and then to shift the exhaust gas pyrometers off the bottom of their dials, so I think they are running at sub-optimum BSFC.


    The yard is getting prices for some 're-manufactured' Cummins 6B (210HP, actually new engines) and JD 6.8 litre in 225HP spec. I think either is a good choice. The Cummins is one the last of the mechanical injector engines available, which has some benefits. But the electronic JD's are pretty nice. I'm just not sure they will be that much better, and the price jump will certainly be noticeable and install costs will also be higher. I'll get those numbers in a few days. Before deciding I am interested in hearing of experiences, opinions etc on other options. And even though I am not fond of the 555's, there isn't anything wrong withe them and an 'external overhaul' might just be the smartest move.

    Oh, and to complete the picture: Gearboxes are MG 506 2.5:1 and props are 30" diameter, 26" pitch. Although the claimed lightship for the boat was 48,000#, if the travel lifts aren't too far off I actually displace around 65,000#. Waterline length is 46ft. Max beam is 15'6", not sure what waterline beam is. Draft is 4'6".
     
  2. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    From people I know and have known they could be hit and miss-either good engines or just horrible.But overall they don't have the best reputation. I suspect much of it has to do with people overloading them.
    And if you need parts,it's going to be very pricy NOS stuff as i don't think the Chinese have done reproductions.

    If it were myself,and the $$ were available and the 210 is enough-I'd throw in the mechanical 6BTs and never again worry about an engine the rest of my life.

    edit.I looked on ebay and in frame rebuild kits are $1500,so not too bad..
     
  3. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    Hi West
    The 6BT seems the logical choice, its where the heart is talking. The head is saying 555 'service' is enough and the those engines still have a lot of hours in them. But, if parts are needed for 555's in the future it will definitely cause a lot of hip pocket pain.

    But nice to consider options before making a decision. I'm scrutinizing the Lugger 1066 at present.
     
  4. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    IIRC they have wet liners as well....

    I'd say if you plan on keeping the boat forever-put in the 6BTs. Otherwise throw them back in.
     
  5. whitepointer23

    whitepointer23 Previous Member

    the 555's are running well and low hours, why change them. the 40 or 50,000 dollars per engine replacement will pay for a lot of diesel.
     
  6. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    Brendan
    I think the 6BT's, here is the US where I am at present, will be in the vicinity of $20k each. Were I back in Australia I probably wouldn't be asking the questions. If I remember correctly, a 6BT reman ex: Brisbane was going to be $30k assuming you had a core to exchange. Just crazy price differentials.....
     
  7. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    $20k!!! WTH!!

    For $4k you should be able to get an entire long block and NO CORE CHARGE with any wear parts new.

    New: turbos $1500, injection pumps $800,injectors and lines maybe $1000,starter $200.and IIRC wet exhaust are around $800.
    Aftercooler-dunno guessing $1000
    Find someone else and pay $10k

    edit:

    http://www.ebay.com/itm/Cummins-6B-...Marine-Exhaust-Manifold-4020066-/160843670786

    http://www.ebay.com/itm/Cummins-6BT...Parts_Accessories&hash=item25724b16ff&vxp=mtr

    I just noticed this engine is brand new..not a reman.
     
  8. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    West, I've seen 6BT remans around the net for the numbers you quote. But as Brendan indicated, live in Aust and suffer the prices there for a serious hip pocket scare!

    The engines I'm talking about are actually brand new engines. They are called reman because they aren't 'Tier whatever' compliant and thus cannot be marketed as new engines. A little loophole that will close soon I'm sure. If I'm spending serious money, I don't want a backyard reman, even though there are some fine folks out there who do really good work. There are shonks too. Too much of a lottery for me when I would soon be very far away and have trouble with redress if required. My 'new' price was $16. But I added a bit on for exhaust mixer elbows and miscellaneous extras. Firm prices in a few days.
     
  9. Aliboy
    Joined: May 2011
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    Location: New Zealand

    Aliboy Junior Member

    Changing engines is going to be expensive. I don't know the 555's very well, but at 270hp and 9.1l they should go way more than 2000hrs, but they also do not have a great reputation. I heard that parts can be expensive now so you may want to check.

    You could consider just doing all the 555's hoses, clamps etc, acid washing all the coolers, and just generally tidying them up. That would be the simplest and cheapest option unless they start giving you problems.

    One thing to think about if looking at smaller engines is what prop sizes and torque you will end up with. Too little of either and control in a heavy sea might be compromised. I run a pair of 330hp's in a 43ft sportfisher and there are times when I deliberately go hunting for an inefficient speed (9 - 10knts) that allows me to carry more 'power' as I go through dangerous harbour entrances etc. Not sure that I would feel so comfortable with a pair of much smaller engines. A friend of mine tried putting a couple of 60hp engines in his 35ft cat to replace the 200's he had thinking that since he only trolled at 7 - 8knts he would save on his fuel bill. End result was that he struggled to control the boat in following seas through lack of prop size and torque.
    Regarding the Cummins and JD, I think either would be OK, but do the rpm's on the new engines allow you to keep the same gearbox ratio and props? I have a feeling that they both turn slower than the 555, but you would need to check. Regarding mech vs electronic diesels, I did the change to electronic a few years back and have not regretted it 4000 engine hours later. I also suspect that the electronic diesel might be more tolerant and fuel efficient at the slow speeds you like to travel at. They tend to control fuel flow more effectively and whilst I saw only a small change at my 18 - 20knt cruise, the savings at 8knt trolling speeds was 20% or more. If however the price jump is too high, the 6B's at 210hp should last you a long time and parts etc are widely available.
     
  10. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    Someone's still marking them up huge-complete factory new ones with turbo were $7k here in Vancouver.
     
  11. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    Cummins are almost ashamed of the 555's. In some places they are not responsive to customers at all, and parts availability is patchy. One of my raw water pumps is new, for the the other I probably should look at replacing. But that's $1000. Just one example of what the future holds if I stick with the 555's. Future parts availability and cost is the big driver in my thinking. Better fuel economy in a repower is just a bonus on the side.

    I've yet to check in detail the prop power demand. But it is around 300HP at 3000rpm. Using the same gear and props, i think I'm going to close with around 200HP at 2400 rpm. The props can likely be re-pitched a little if required.

    The point is, the 270HP engines are not enough to plane at 20 knots, yet far more than needed for displacement speeds. They are an in-between size. Sure I'd like to plane, but with the fuel bill that would result I would not do it often - I just don't need to rush back for work anymore.
     
  12. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    Vancouver is just up the road as it were, I'm in Port Townsend. If I decide on the 6 BT's then some hard bargaining seems to be called for. When you say 'were' - how long ago and who had them? Truck or marine (heat exchanger included)? You are getting me thinking I could get 2 for the price of 1, and I'm always interested in those deals!
     
  13. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    An acquaintance got them from a marine supply place in North Vancouver.
    I'll look around...this was 3-4 years ago or so.

    Also consider then when/if you decide to sell,I'd say the newer engines will add to the value what you put into it and make it easier to sell.

    I'm sure you're considering the possibility of major 555 problems,and back home in AUS what it will cost you then. :(

    Is the boat in PT? Or in AUS and you're looking to ship engines home?
     
  14. WestVanHan
    Joined: Aug 2009
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    WestVanHan Not a Senior Member

    But I'm telling you...that ebay ad is a new Cummins long block...$4k..think about it.
    Buying new stuff and you'd be into them for $10k each.
     

  15. Brian@BNE
    Joined: Jan 2010
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    Location: Brisbane, Australia

    Brian@BNE Senior Member

    I plan on keeping the boat forever to pick up on one of your earlier comments, but have yet to figure out how to live forever. Yes, a driver for repower now whilst I actually have an empty space in the engine room(courtesy of need to replacing fuel tanks) is that some of the costs are sunk/written off to that need. The 555's could last forever ... or not. The cost of significant repairs, or repower back in Aust is really scary. There does seem to be a market here in the PNW for 555's. There are a lot about, and people are interested in having a spare one if an opportunity arises. I need to find someone who would like to stash a low-hour pair to ease my cost of new engines.

    I'm still accumulating info on how much power I really need. In smooth conditions 200HP in total will get me a 10 kn cruise. How much reserve power is enough? I'm thinking around 350HP min. Not sure whether that should be for Continuous rating or medium duty. The 6BT's at 210HP each should be fine. Best option so far for a little less is the Lugger 1066A.

    I'm on hardstand in Port Townsend for the stabiliser install and significant electrical work, DC and AC. With the tank work added, the boat is going to be here a while. I may leave and then come back, but whilst the weather is good I can work on the brightwork amongst other things and be on hand to guide some of the little decisions, which I like to do. Big decisions can be managed by phone/email from anywhere...
     
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