Page 1 of 2 12 LastLast
Results 1 to 10 of 20
  1. #1
    Join Date
    Jun 2011
    Location
    Volos-Athens
    Posts
    4,671

    Default Impeller looks a bit tired...

    so since I've removed, cleaned, changed o-rings, reassembled and refitted all heat exchangers in both engines, I thought I should check/replace impellers as well. Especially as I found a small bit of a vane on the port engine CAC.

    Started with the easy one (port) as impeller is in the v.easy to access space between the two engines.
    Had already replaced the flat headed screws with nice ss alen ones, two minute job to remove the cover plate.
    A bit puzzled as what I saw was rather unexpected:



    So got a screwdriver and tried to see what's behind , rather worn impeller behind all the salt deposits:


    impeller removed, loads of salt deposits working like sandpaper on the impeller rubber:


    that's how the housing looks like after a bit of cleaning, will come back with some salt remover spray and water to clean it properly:


    and the impeller:







    Now, I obviously going to replace it, have a Jabsco Profile Y kit with silicone/grease, gasket and even a rubber plug for the centre/shaft, but that's not the point.
    This impeller was fitted new on Aug 2015 at the end of the refit. Engines have clocked around 120h since in three seasons. Is that condition acceptable?

    I'm asking as my friend with CAT engines has the boat for around 8yrs (bought s/h) and each year opens up the cover plate, has a peak, looks brand new, retightens the cover plate, that's it.
    Also the next door neighbour with a single IVECO 300 engine replaced the impeller on the 6th year and the one removed looked fine to me.

    Am I missing something, or is there's something wrong with mine?
    FWIW, engine was running fine, was actually cooler than the stbrd one by 3-4 degrees (port engine had heat exchangers cleaned back in 2015, stbrd cleaned last week)

    Haven't bothered to remove the stbrd engine yet as I need to get a couple of more impellers will do over the w/e

    cheers

    V.

  2. #2
    Join Date
    Apr 2011
    Location
    Boat- SoF
    Posts
    4,740

    Default Re: Impeller looks a bit tired...

    They are not OEM install those engines iirc ?
    Where I,am going with this is that they look free draining caused by the relative pump height of the none originally installed Ivecos and basically the WL

    By way of example my pumps are mounted low relative to the main engine mass are level with the WL so I suspect don’t free drain and stay primed .

    Question is , if the clock was turned back to the new build project would the Iveco guys sign that off or return with a different pump mount position and recommend that to the builder ??

    Similar considerations should be given to the strainer location with regards the WL and the lid top height .

    My 0.02 p worth .

    Impeller certainly ready for replacement.I believe there’s different quality with theses as well .

    Do you regularly run them in the winter ? I realise some times it’s on the hard.
    That’s another reason I run mine every month in the off season to exercise the rubber impellers helps prevent a “set “

    But your problem is a draining down pump body .

  3. #3
    Join Date
    Jan 2009
    Location
    Stratford on Avon
    Posts
    11,050

    Default Re: Impeller looks a bit tired...

    I change my Cat impellers every 3 years. They come out looking like new. Quite a hassle as I have to take the pumps off to access the impeller. Port engine a real struggle for access, dangling through the saloon floor. Had to change the shaft/bearings on the stbd pump last year as the seal was leaking. Sterling pumps, a rubbish design.

  4. #4
    Join Date
    May 2001
    Location
    Jersey/Antibes
    Posts
    22,357

    Default Re: Impeller looks a bit tired...

    Looks odd vas. My small genset impellers fail at 250hours quite consistently and never have salt deposits. My main engine impellers on all boats I've ever had have zero salt and last 2 years +250 hours and look perfect - I change them for the hell of it. Youve got something wrong but I don't know what.
    I totally don't buy that impellers can set in a month or whatever as Porto worries. Quality OEM impellers that are properly cured in manufacture won't post cure into a new shape (that being the main cause of set) at normal resting temperature of a berthed boat ie 20 deg C. Of course a badly made rubber component will set into a new shape if kept stretched/compressed for a month at much higher temps.

  5. #5
    Join Date
    Sep 2002
    Location
    South
    Posts
    16,458

    Default Re: Impeller looks a bit tired...

    The impeller isn’t the problem, it’s getting shredded by the deposits.
    I’d be looking upstream for something that is dissolving to cause those deposits.

  6. #6
    Join Date
    Apr 2011
    Location
    Boat- SoF
    Posts
    4,740

    Default Re: Impeller looks a bit tired...

    I wonder if there’s been any wear of the pump housing or cover plate?
    The new rubber vanes I suspect will stretch out and seal against the pump house inner barrel , but even with a new rubber if there’s been wear on the cover plate that might not re seal up satisfactory.

    So it might struggle to prime as the salt has basically and unwittingly contributed to the air seal at initial start up .

    There’s an awfully thick ( relative to pump seals ) thickness of salt behind that cover plate .

    More on “ set “ for folks deliberations
    http://www.galmukoffmarine.com/sx-html/
    Last edited by Portofino; 18-04-19 at 22:49.

  7. #7
    Join Date
    Nov 2002
    Location
    Colwell Bay
    Posts
    5,525

    Default Re: Impeller looks a bit tired...

    What material were the original cover plate screws?

  8. #8
    Join Date
    May 2001
    Location
    Jersey/Antibes
    Posts
    22,357

    Default Re: Impeller looks a bit tired...

    No way that impeller pictured was like that after "months" unless they meant 36, 48 or 60 months. You can find anything you want on the internet Porto, as you do often. https://wiki.tfes.org/A_hundred_proo...is_not_a_globe

  9. #9
    Join Date
    May 2001
    Posts
    15,081

    Default Re: Impeller looks a bit tired...

    Quote Originally Posted by FlowerPower View Post
    The impeller isnít the problem, itís getting shredded by the deposits.
    Iíd be looking upstream for something that is dissolving to cause those deposits.
    The deposits are surely a mixture of salt and calcium in the seawater, but you may be on to something FP.

    Have you had any overheating issues on that engine Vas? It looks as though you have seawater sitting in the pump and not draining away, which seems most odd. As everyone else has said, when I change my impellers they look virtually new.

    However, I did have an issue with my cooler for my stabilisers. My port engine was gradually producing more and more steam from the exhaust, but not overheating. I cleaned everything, or so I thought, until the downstream tail of the stab heat exchanger, (that was first in line from the inlet seacock and strainer) broke off!! It was then that I saw that it was almost completely clogged with the sort of deposit shown in your pic, with just a small pencil sized hole in the middle allowing just barely enough cooling water through.

    What I hadnít realised is that there were 2 pencil anodes in the cooler, so these hadnít been changed in about 7 years, but strangely only the downstream bronze tail exiting the cooler was blocked, the upstream one was as clean as a whistle.

    So maybe as FP says, there is some corrosion issue going on upstream of the pump that gradually seeps back once the engine has stopped and over time, causes your clogging issue. Do you have any anodes upstream of the pump? If so, have they been checked regularly. After my issue I read that pencil anodes should be checked every 4 months. But Iíd bet that most are looked at just once a year, mine certainly were, apart from this cooler where I didnít even know there were anodes!

    Please keep us updated as to what you find.

  10. #10
    Join Date
    Jun 2011
    Location
    Volos-Athens
    Posts
    4,671

    Default Re: Impeller looks a bit tired...

    thanks guys for an interesting set of ideas/Qs.
    on with the replies then!

    PF:
    MiToS was reengined before my ownership from DD. Will check carefully the seawater level argument and draining as I think it is semi-draining, feel that the W/L is halfway the pump housing.
    Housing is not worn (from what I can see at least), it's a bit awkward to bend down there so taking lots of 16Mpix pics and checking them with specs on
    Plate is worn on the central boss thing, ie a grove where the central rubber tube is just outside the metal spline. Plan is to turn it over for now.
    Vanes are not really deformed, they hold to their shape quite well (and better than the yanmar gen engine!), they're just shreaded by the salt deposits.

    P:
    at least mine are an easy reach comparatively, and no play in the shaft and no leaking at the back

    JFM:
    IIRC I'd bought them as nitrile ones having read that they're better than stock ones. Mind, the Jabsco one I have in it's box also says nitrile.

    FP:
    upstream there's 1.5inch plastic all the way! Trudesign injection/seacock, rubber hose with wire to plastic strainer and then hose again to pump body. All look fine so nothing to dissolve, but LJS may have a point (re downstream anodes!)

    BB:
    don't remember! either galv steel or ss, probably galv. Bearing in mind that I didn't have a paper gasket and used some instant seal, a film of it I had to remove yesterday when I opened it up, I assume that there was some isolation between and anyway haven't seen any suspicious pitting or anything, faces completely clean and smooth

    PF:
    I'm with JFM on that, this impeller was probably "set" for a 4-5yrs in that position, not just through a winter, unless run dry on the hard for 5-10mins to heat up nicely and then left to cool in form

    JFM: managed up to #10 in the list and gave up...

    LJS:
    Engine running v.cool, never ever overheated!
    However, first pencil anode is 20cm after the pump body on the way up to the CAC. Second pencil anode is on the CAC endcap.
    I've picked up the second anode (facing down and held in the bronze 24mm nut by just hammering it in...) on the gbox oil cooler (the natural place to loose it as it drops straight into it after a downfacing elbow).

    First anode is facing upwards so not really easy to disslodge/wear it self and drop back down to the pump body. Could have happened as I don't recall the condition of all anodes over these three years. I do replace them annually and they really don't come out good, so I should do it more often.

    So out of all ideas:

    A. I may have a drying pump assembly which I gather is a bad thing (or not???), but getting a slightly longer hose from the strainer and siphoning it up before going down to the pump should solve that, right?

    B. I may have bits of dissolving pencil anodes dropping down to the housing and helping the destruction of the impeller as well as helping the built-up. Plan is to switch to screw on pencil anodes, need to machine new bronze plugs with internal M6 (or M8) threads to bolt them on and need to start checking anodes more often.

    will come back with some measurements and photos of sbrd impeller housing

    cheers

    V.

Page 1 of 2 12 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Latest YBW News

Find Boats For Sale

to
to