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Cat 3306's...

Discussion in 'Engines' started by Justin L, Aug 4, 2025 at 11:47 PM.

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  1. Justin L, Aug 4, 2025 at 11:47 PM
    #1
    Justin L

    Justin L New Member

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    Considering an older cruiser with Cat 3306's, approximately 7400 hours, reportedly well maintained with extensive records. Some of my boating friends suggest that you absolutely need to get the cylinders scoped as part of the mechanical inspection to get the full picture and others state that is not necessary with a high quality mechanic/surveyor. Curious on your thoughts, recommendations and experiences.

    Thank you in advance!
  2. boatpoor, Aug 5, 2025 at 4:07 PM
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    boatpoor

    boatpoor Active Member

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    I don't know how you would scope the cylinders on that engine, the only way in is through one of the valves . Those are good engine though, I have a generator with over 10,000 hours and a smaller one (105kw ) with a 3304 that has more than that . Never had a head or oil pan off either one.
    I don't know if you could get a scope through the glow plug holes and down into the cylinders or not.
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  3. Capt Ralph, Aug 5, 2025 at 5:10 PM
    #3
    Capt Ralph

    Capt Ralph Senior Member

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    Parts will be an issue. Good engine but not built in the high numbers to receive lots of End Of Life (EOL) support.
    I will call it rare in a boat.
    If I recall, discontinued around '95 or shortly after.
    Call a Cat shop and ask them if support is available.
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  4. Justin L, Aug 6, 2025 at 4:30 PM
    #4
    Justin L

    Justin L New Member

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    Thanks for the thoughts! I talked to a local cat shop and they said parts/support should not be a problem.
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  5. K1W1, Aug 6, 2025 at 7:23 PM
    #5
    K1W1

    K1W1 Senior Member

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    The post pre combustion engines had pencil injectors, a borescope fots down one and they do not use Glow Plugs like the pre combustion engines
  6. K1W1, Aug 6, 2025 at 7:27 PM
    #6
    K1W1

    K1W1 Senior Member

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    What is the vintage of the engines? The 3306 (non pre combustion) had many changes after delivery in an attempt to get them clean burning and improve the emissions. If ever you have one in bits please be sure to look at the part numbers of the internals and check the Inj pump timing before removing it as this was another mod done in the field to aid clean burn that didnt use the original marks. Its easy to tell if its been advanced if you know what to look for. Its been more than 30 yrs since I turned a wrench on one but still have a pretty clear recollection of what we used to do to them in order to reduce the black snow.