Cummins Marine Diesel Repower Specialists › Forums › Cummins Marine Engines › 1999 Sea Ray 450 Express Bridge w/6CTA 430HP Diamonds

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  • April 16, 2021 at 9:48 am #113528

    Kevin
    Participant
    Engines: 6CTA 8.3M
    Location: Boggy Bayou
    Country: United States

    Hi All,

    After two failed purchase attempts this winter due to inspection issues, I am on attempt #3.

    I have stumbled on a well-kept boat that had a starboard engine failure (severe overheat) and subsequently replaced about 75ish running hours ago (April 2019). At the same time, the starboard engine was replaced the owner had the mechanic go through the top end of the port engine and did a bunch of maintenance on all of the components to include all of the coolers (I have the work orders in hand and annual maintenance for 2020). I am having a hard time getting an engine surveyor, but I have a deep mechanical background (dad’s RV business and then US Air Force) and I decided that on engines without an ECM there isn’t much to be done but oil samples, a thorough once over for leaks, and using my borescope to take a look at as much as I can during the survey (will bring a few tools and see if I can peak at compressor and impeller on the turbo and at the inlet of the aftercooler). I have a good hull surveyor who will pull the oils samples, so I am going to go Han Solo on the engines, transmissions, and generator.

    As a former aircraft and vehicle/RV mechanic, what am I going to miss that a marine mechanic would know to look for? My intuition tells me the exhaust is my biggest blind spot, but are there other things I need to look at on the 6CTAs?

    Thx in advance and hopefully I get to add a boat to my profile soon!

    Kevin

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  • April 17, 2021 at 6:35 am #113567

    Kevin
    Participant
    Engines: 6CTA 8.3M
    Location: Boggy Bayou
    Country: United States

    Hi Larry,

    Great info! Thanks.

    Great insight on all the trouble spots on the boat. Would love to see images of your exhaust setup?

    I agree, this forum is great…lots of helpful folks and the knowledge base is incredible. Will certainly be purchasing from Tony and Rob.

    Hope your day on the boat is great!

    Best,
    Kevin

    April 17, 2021 at 6:23 am #113566

    lpmcc
    Participant

    I own the same boat/engines

    I own the same boat/engines for 10 years. It has been great, but I have a few comments: You will hear that your exhausts are “doomed” to fail as they hold seawater when the engine is off. If they leak internally, seawater will flood/ruin your engines. I had mine redesigned/replaced about 7 years ago, although the original ones looked brand new.

    You will want to be sure these engines get up to 2600+ RPM full throttle. Any less, and the engines are overloaded. The aftercooler inlets are not discolored brown (a possible indication of overloading), but that could be because they are new or painted.

    I do all my own maintenance and some is a pain, especially outboard of the stbd engine. I’m a big guy but I’ve been able to do all, including removing aftercoolers and replacing exhaust elbows, without pulling off the big cockpit hatch.

    It does look a messy down there, but can be cleaned/neatened up. Be sure and check everything thoroughly.

    Be sure engines are stone cold for a start up check. They will probably smoke a bit at start up, but go away in a minute of so. At first throttle up on plane, you will see black smoke, but again, should dissipate quickly.

    Bring an IR temp and check all. Compare to each engines

    I have 2,200 hours on mine. Love them, best engines I have ever had. Tony and his team have been great. I’ve bought all my parts from them, and they are always helpfully with any questions. You have come to the right place.

    And if you don’t know about moisture in the hull sides of this particular Searay model, especially around the ER intakes, do some searching. Not all are bad, but you need to check it out. And check out the deck/windless area for core moisture. And the master v-birth side shelves. Those port hole windows can leak and all that carpentry can get wet and rot.

    Actually, off to the boat now, but happy to answer any questions you may have.

    Good luck!

    Larry

    April 16, 2021 at 2:45 pm #113551

    Kevin
    Participant
    Engines: 6CTA 8.3M
    Location: Boggy Bayou
    Country: United States

    Harry,

    Thanks for the inputs. I’ll check out the access to the maintenance items for sure. I do know that the cockpit sole comes off for major work, but hopefully we won’t have too much of that anytime soon!

    Best,
    Kevin

    April 16, 2021 at 2:42 pm #113550

    Harry Karaoglanian
    Participant

    I’ll leave it to the guys on here about that exhaust design.

    Like I said – not a professional and im only stating stuff that I’ve read on here from Tony and Rob. If I didn’t have access to the other side of the engines, I wouldn’t buy that boat. Looks to be a maintenance nightmare unless you’re good at yoga! Lol.

    April 16, 2021 at 12:08 pm #113542

    Kevin
    Participant
    Engines: 6CTA 8.3M
    Location: Boggy Bayou
    Country: United States

    I can get those images next week on the survey. Will be able to grab shots of the outboard sides of the engine even without access as my borescope has a 90 degree attachment.

    I have seen other shots of these boats during my search and exhaust leaves the turbos at the front of the engines (which face the stern, V-Drive) and go pretty much straight out the back so it doesn’t look like water will run back to the turbo after shutdown, but I will have to look at the slope of the exhaust and where the water is injected. Attached one of a better look at the port engine config.

    April 16, 2021 at 11:43 am #113539

    Harry Karaoglanian
    Participant

    Do you have access to the other sides of the engines?

    Any photos of the exhaust layout? Where is seawater being introduced in to the exhaust?

    April 16, 2021 at 10:19 am #113532

    Kevin
    Participant
    Engines: 6CTA 8.3M
    Location: Boggy Bayou
    Country: United States

    Hi Harry,

    Thank you for the reply!

    Yes, the overheat was at 850ish…lost the engine accessory drive belt and sweet water pump stopped pumping. As part of the engine replacement, all gauges and senders were replaced. The owner just didn’t know it had happened until it was too late.

    Yeah, you are spot on with the aftercooler…I could see the charge-air side, but not the sea-water side. I had thought I could confirm that the cleaning of “all coolers” on the work orders was actually completed. Thanks for the vector check on that one.

    Images attached (I have the high res versions but they are too big).

    April 16, 2021 at 10:10 am #113531

    Harry Karaoglanian
    Participant

    Sorry I read @ 75 hrs but it seems like you’re saying 75 hours ago.

    Is it fresh or salt water boat?

    April 16, 2021 at 10:07 am #113530

    Harry Karaoglanian
    Participant

    So you have photos of the engines? Post them here. I’m no professional but the guys here are and will tell you.

    The 450 diamonds are beasts. Crazy to see an overheat @ 75 hours- had to be pure negligence by the owner. That’ll tell you a lot about how the boat was kept IMO. Not to deter you from purchasing it but that right there would tell me to walk away.

    When I was purchasing – we did oil samples on numerous boats – all of them all over the place and useless. The boat we purchased after doing oil changes and re-testing and following a ROUTINE SAMPLE the samples were coming back great. One sample would mean almost nothing, good or bad.

    I can’t imagine you’d see anything with the boroscope- the aftercooler needs to be pressure tested, you’d have to unscrew the end caps to see, same with the heat exchanger and I doubt anyone would allow you to do that on a survey – plus you’d have to change out gaskets when you do, or at least I would.

    Exhaust design is crucial- make sure that’s good to prevent future problems with the turbos.

    A proper sea trial with WOT test, fuel burn (if possible) and speed/rpm ratio based on performance with the hull, will tell much more than someone just walking around in an engine room. Make sure the rpms are checked with a phototach.

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