Liner damage please help.

Discussion in 'Help Wanted' started by grendel, Jun 8, 2016.

  1. grendel

    grendel Member

    Yesterday I pulled out a liner from a Cummins engine, because water was leaking to the crank case.
    The engine had previously run 65000 hours, followed by a complete overhaul. Bearings, liners, pistons and heads were exchanged.
    After the overhaul, the engine has now run approx 35000 hrs.
    I haven't seen this extent of damage to the liners when the engine was overhauled. Also, we have another of the exact same engine with the same running hours and we exchanged two liners three months ago and they were fine on the water side.
    Cooling water is a ready mix, used in both engines.
    I have seen cavitation damage before on liners, but never to this extent. It has gone right through the wall. I can't help and wonder if there was a issue with the casting material.
    May I please have your views on this?

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    Thanks,

    Hubert
     
  2. petternut

    petternut Administrator

    Have you asked Cummins?

    cheers
    Roland
     
  3. shaggy3000

    shaggy3000 Member

    This is very common on a Cummins are you using dca additive or a water pre filter? Used to be very common on the Cummins C series where it would eat the liner seat away as you have said fill the sumo with water.
     
  4. picklesquirt

    picklesquirt Member

    Have see similar things in non ferrous castings. That liner needs to be sectioned, potted in resin and polished and then looked at with some serious magnification. Best done to both the undamaged and damaged area. Looks very like inclusions in the casting.
    If you have pulled out more than one liner does it always happen in the same orientation?

    Ewan
     
  5. highrange

    highrange Member

    Looks a lot like Danish Blue cheese to me ........ is that what they mean when they say parts are made of cheese? :lol:
     
  6. grendel

    grendel Member

    Hi guys,

    I have not seen it this bad before. My idea exactly that there must have been bad sections in the cast iron. I can't make any sense of the place of the damage in correspondence to the water holes in the block or the position of the liner. Most damage is on opposite sides, but not 180 degrees, so that does not really help.

    Now, Mr Google has taught me today that many Cummins parts are made in China nowadays. Both genuine and fake.
    This engine and the other one were overhauled after 65k hours and all liners came out fine (but worn of course!). This was the first overhaul after new.
    Now the spare parts that went into these engine were supplied by a cummins dealer that overhauled these engines.
    These were bad times (they went bankrupt a couple of months later) and although all genuine parts were used, now I am not so sure these are of the same quality that Cummins used new.
    Also: I am not so sure if spare parts supplied by cummins to third parties are of the same quality as they use in new engines.
    Or: Over the past three years Cummins has taken to buying parts from other factories that don't supply the same quality.

    When I pulled out two liners from the other engine, they were rather worn on the inside and because that surprised me i had them checked by a third party to see if they were genuine, which was confirmed. I only wonder now if there are different grades of "genuinity"

    Whatever the truth, there is no getting away from the fact that these liners fail after 35k hours and the originals after 65k hours.

    I have had a look at the bearings today as well and these tell the same story. They look worse that the old ones did.

    Hubert
     
  7. picklesquirt

    picklesquirt Member

    Age brings cynicism ( usually well placed ). We had some copper coils, wound with 3/4in dia pipe, our drawings specified "high conductivity, oxygen free and no phosphorus " copper . However they overheated. The supplier produced "certificates of conformity", in good faith, for the material from the mill. In fact we had to go to a specialist test house to measure the very low but critical levels of phosphorus.
    C of C's guarantee nothing. Cummins may well have fallen into the same trap.

    E
     
  8. lambe

    lambe Member

    I understand Cummins has also had issue with their coolant additives recently , in particular the OAT type. don't always assume the defect is in the bit you see :shock:
     
  9. TangyeDan

    TangyeDan Active Member

    Cavitation can also be made worse with the flow characteristics of the coolant around the block. Did you change the water pump at overhaul? Was it the same flow rate as the old unit?

    Dan
     
  10. grendel

    grendel Member

    Hi,

    The liner and bearing shells were inspected by the insurance company yesterday. My suspicions were confirmed. These parts are genuine Cummins, made in India and definitely not of the same quality that Cummins uses in new engines.
    There is no way around this as that is what Cummins supplies. Take it or leave it.
    I will post a picture of the bearing shells later. They also look worse than the ones that came out during overhaul.
    The result is that these parts start failing at 30-35k hours, where the original parts would fail at 60-65k hours.
    If we had known this, we would never have overhauled these engines. We hope to squeeze another 5-8000 hours out of them and then they will be replaced with another brand.

    Hubert
     
  11. petternut

    petternut Administrator

    A classic example of how to lose Customers! Saving pennies to lose pounds.

    cheers
    Roland
     
  12. pp-admin

    pp-admin Member

    iam going back many years but there used to be a black tar gloopy kind of rubbery paint made by ici which was brushed on the water facing side of cast iron liners to stop cavitation and rust damage. i have not seen it for years and years but i still have (somewhere !!! ) a few new old stock petter liners that have this stuff factory applied; they are at least 60 years old.

    i cant for the life of me remember what it was called but i have removed knackered old liners that had this stuff applied from new and they have suffered very little of either rust or cavitation and the original paint is reasonably intact.

    i did once have a tin of this stuff and i distinctly do remeber that it absolutely stank of chemicals like nothing i have ever encountered before or after !!

    cavitation is not to be underestimated and occupies the nightmares of marine architects and marine propulsion engineers the world over. its one of mother natures nasty little reminders that we humans are minnows in the universe !!

    gerry
     
  13. grendel

    grendel Member

    I would like to update on an old post.
    Since this post, we have exchanged several parts, until early last week starboard main engine failed. It jammed solid and after a couple of hours dismantling, I found that several main bearings had failed and also the big end bearings of #2 cylinders. Since the vessel was loaded, I decided to continue to the discharging port with one engine, which was only two days away.
    After discharging, we set sail to a ship yard in The Netherlands for repairs. Only 10 miles from our destination I increased load to 90% to overtake another ship and at that moment the other engine stalled as well. Jammed solid.
    A tugboat has assisted us to the ship yard and there we soon found out that the second engine main bearings also failed, leaving the crank shaft blue and several conrods as well.
    Both engines are a total loss.
    Getting to the bottom of this, we have now found that the "genuine Cummins dealer" indeed has cut costs by ordering "non genuine" parts from China. As mentioned before, he went bankrupt.

    Let this be a warning. I can only imagine how many "genuine parts" turn out to be made in China. Especially when bought from the internet. If we know that literally everything is being reproduced in China, it forces us to double check everything.
    We had the overhaul done by a genuine Cummins dealer and on the bill it is mentioned that genuine cummins parts would be used. What some people will do for money,...........

    Both engines are now removed and will be replaced.

    Hubert
     

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