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Looking for better DD / Bertram motor mounts

Discussion in 'Technical Discussion' started by Capt Ralph, Oct 19, 2019.

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  1. Capt Ralph

    Capt Ralph Senior Member

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    13 years ago, I tried to align my 12V71TIs engines in our 58' Bert MY.
    I soon discovered a hornets nest.

    All the rubber in the engine mounts were crushed and bottomed out.

    Working with a rubber shop here in Jacksonville, I purchased high pressure rubber doughnuts that would fit nicely and reassembled as best as I could.

    Well it did raise the engines back up, but adsorb vibrations,,, NOT.

    It's time for the correct mounts and for the boat to stop vibrating as we cruise. My old bones would be more happy also.

    Any mount experts out there?
    Bert Main Motor mount pics 001.jpg Bert Main Motor mount pics 002.jpg Bert Main Motor mount pics 003.jpg Bert Main Motor mount pics 004.jpg
  2. PacBlue

    PacBlue Senior Member

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  3. RER

    RER Senior Member

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    What about fabricating them from sheets of rubber skirt board - EPDM rubber ...it has fiberglass cloth lamination in it. Most industrial supply companies sell a variety of types and sizes. I've used it on machinery in a number of very heavy industrial applications. It's almost indestructible. I used to get it from McMaster-Carr.
  4. PacBlue

    PacBlue Senior Member

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    I think the effective isolation and vibration control of marine diesel engine mounts requires a bit more technical analysis than picking rubber materials randomly. Even if they are for a stationary land side application .

    Here’s another marine supplier: https://novibration.com/products/specialty-isolators-marine-mount-series/?portfolioCats=37

    Between the three , you should be able to find the right mount for your hp, rpm and weight as well as budget.
  5. Capt Ralph

    Capt Ralph Senior Member

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    Been looking at those Barry mounts for a while. They seem to be Standard on Cummins installs.
    It's that cast alloy base I don't care much for.
    But honestly, in all these years, only found one that cracked and suspected bad & wet installation then.
  6. bayoubud

    bayoubud Senior Member

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  7. RER

    RER Senior Member

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    Those aren't exactly cutting edge technology motor mounts. Wouldn't surprise me if the OEM spec was Skirt Board Rubber. I've used it on equipment that runs 24 hours a day six days a week with far more required from it than cushioning a DD 12v71TI and under conditions far more extreme than a Bertam engine room.
  8. PacBlue

    PacBlue Senior Member

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    Skirtboard Rubber for seals and gaskets and industrial equipment applications- sure.
    I can’t see what the benefit of a fiberglass cloth imbedded in the rubber does for a marine Diesel engine mount. Shed some light on this.

    Industrial Applications are typically not dynamic - they do not have to deal with accelerations and g loads while isolating noise and vibration and taking up the thrust load of a soft mounted reciprocating engine in a moving platform. What are far more requirements?

    I would talk to the marine mount guys and get the right product without guessing on replacement rubber.
  9. RER

    RER Senior Member

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    Not for seals and gaskets. For vibration isolation. There is no need for me to make the case. The Internet is awash with EPDM SBR rubber isolator engine mounts. I simply suggested if Ralph was looking to keep his exhisting engine mounts and change the (obsolete?) rubber he may be able to fabricate them from sheet material. All new engine mounts are a good option also.
  10. cleanslate

    cleanslate Senior Member

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    CR, what is holding your engine in place now while those are off?
  11. Capt Ralph

    Capt Ralph Senior Member

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    Those are pictures 13 years ago. You can see the original rubber had failed and crushed in. The mounts were down to metal on metal then.
    The replacement rubber did raise the mounts up but to hard and it's like solid mounts still.
  12. boatpoor

    boatpoor Member

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    We do a lot of service work for both Lord and Toyo. I'll make some calls over the next couple of days and see what I can find out. They make engine mounts etc for automotive, aerospace and marine.
  13. cleanslate

    cleanslate Senior Member

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    Maybe Grainger has something / rubber you could use.
  14. Capt Ralph

    Capt Ralph Senior Member

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    I think they were ACE mounts back then but I really want some vibration relief on my old back and boat.
  15. Capt Ralph

    Capt Ralph Senior Member

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    I'll try to get some installed pics and measurements online tonight.
  16. boatpoor

    boatpoor Member

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    Measurements and how many per engine? We will need to know how many square inches of rubber per engine. What gears do you have?
  17. Capt Ralph

    Capt Ralph Senior Member

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    I'm going to flood this post with pictures of the double post rear mount and single post forward mount.
    The clutches are TD514s behind 650hp 12V71TIs.. The rear mount has a plate from the clutch case and the flywheel / bell housing.

    You can also notice the thin and thick shims to raise and align the engine.

    Attached Files:

  18. Capt Ralph

    Capt Ralph Senior Member

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    More pics including the front left mount.
    Big shims up here.
    Measurements coming in a few.

    Attached Files:

  19. Capt Ralph

    Capt Ralph Senior Member

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    The two studs in the rear look close to 10 1/8" center to center.

    Fat 21 1/2" LOA.

    3/4" studs.

    Attached Files:

  20. Capt Ralph

    Capt Ralph Senior Member

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    Need new mount height (bottom nut or shim) to be adjustable from 2 1/2" to 3 1/2".

    Attached Files:

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