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Engine Survey Cost Reality Check

Discussion in 'Technical Discussion' started by Cruz, Apr 14, 2017.

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  1. Cruz

    Cruz Member

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    A friend looking to do a comprehensive survey on twin Detroit 12V72-TA's and twin 20kw generators received a quote just above $5K from a highly regarded Detroit outfit in the south. He's not looking to skimp but never having been down this road before was looking for a reality check, particularly on the 40 hours of labor. The quote is inclusive of parts, labor, travel time, mileage, EPA & those pesky misc. charges. The shop is about 25 miles from the boat so with the back & forth over three days the $180 for mileage is not surprising. Parts total around $850.

    For the mains they'll extract oil, coolant and fuel samples for both engines and send for lab analysis. Complete visual inspection, bore scope inspection and compression test. He is told the compression test eats up much of the labor hours. A scope only could be done but obviously wouldn't tell the whole story and, again, he's not looking to skimp.

    Additionaly, they'll extract oil samples for both marine gears and send for analysis. Complete visual inspection of both units. Same for both gens.

    It will be two men for the first two days of inspections and one accompanying the sea trial.

    They can bore scope through the air box drain covers on the block and could save parts and labor if there is no compression test. Otherwise they will be bore scoping through the injector cup since the injector has to come out to do a compression test. Again, can't imagine not doing a compression test if he wants the full picture.

    Thanks for any feedback.
  2. olderboater

    olderboater Senior Member

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    How old are the four engines and how many hours do they have?
  3. Cruz

    Cruz Member

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    Engines (12V71TA's - originally posted incorrectly) have around 300 hours since rebuilds done several years ago. The boat has not been used at all in many months and clearly had light use prior. 1500 original on one gen and, unless this is a mistake, only 110 on the other. Obvious concerns there on a 24 year-old vessel.
  4. Fishtigua

    Fishtigua Senior Member

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    I wish more Owners/buyers would spend the $5k on a survey, will save them thousands in the long run. Simple.
  5. olderboater

    olderboater Senior Member

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    Based on ages and usages and the fact the engines are long ago rebuilds, I think the price quoted is reasonable. Others may know some reputable engine surveyors for less but it won't be significantly less.
  6. Cruz

    Cruz Member

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    That's what we figured but based on zero experience with this set of circumstances. Thanks for the feedback OB & Fishtigua.
  7. Pascal

    Pascal Senior Member

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    Compression checks on detroits are the reason for the costs. After reinstalling the injectors you have reset the timing. Frankly if they don't smokenkna cold start, if the borescope is clean and oil analysis comes out good you usually don't need a compression check
  8. dennismc

    dennismc Senior Member

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    Many owners will object to a compression test, they do not want their engine partially taken apart and put back together, who knows the after affects of the tests and re assy. who would be liable if there are engine problems for the original owner should the deal not go thro. ?
  9. Cruz

    Cruz Member

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    Both of these things being said, if the buyer is comfortable with the cost and the owner does not object to what's needed for the compression test, would you say it's a worthwhile process in order to get the full story and peace of mind it will provide assuming everything checks out?
  10. bayoubud

    bayoubud Senior Member

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    Sounds like the practical process to follow.
  11. Danvilletim

    Danvilletim Senior Member

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    I'd insist on having the mech on board for a sea trial first. They need to observe how they are running, temps, vibrations first..
  12. Bill106

    Bill106 Senior Member

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    A lot depends on the experience of the mechanic doing the work. Around these parts the number of what I would call good Detroit mechanics is dwindling by the day. If, and it's a big if, I had one of the old pro's I would be perfectly content if he peeked in the air boxes and said the cylinders looked fine. He'd be looking for broken ring lines on the cylinder walls and the spray patterns on the tops of the pistons for possible clogged injector tips. You can't see everything through the air boxes but you can see a good bit. That and a heat gun on the exhaust ports while running will tell a lot about the health of the engines. If you're not sure of the level of experience, go the full monty and break down the rack to check compression (and everything else detailed). After only 300 hours it wouldn't hurt to go through the rack anyway.
  13. captainwjm

    captainwjm Senior member

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    PO of my former boat had compression checks done on 1989 8V9s due to low hours [Great Lakes boat]. Got clean bill of health from surveyor. Took possession in Detroit, headed for Chicago. Less than a day out of Detroit, blew [his term] the port engine. Long story, but attributed to improper reassembly; litigation ensued.

    So, I agree with the comments above; have the surveyor on the sea trial, and absent a darn good reason, avoid the compression check.
  14. Cruz

    Cruz Member

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    Thanks all for the valuable feedback. They are considered a top shop and the lead mechanic on this a real Detroit guru. But the risk of something like what captainwjm mentioned is definitely cause for pause. He did make it clear that, in his opinion, the bore scope is more valuable than the compression testing at this stage, stating that it is possible to have wear inside the cylinder and still be within acceptable range for a compression test meaning they could see an issue with the bore scope before it even shows up on a compression test.
  15. bayoubud

    bayoubud Senior Member

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    Might be worth doing the visual inspection plus reviewing engine/gen maintenance records since SMOH before surveys/ sea trials, especially with sitting for a long time. Might need a bit of work before running the engines/gens.
  16. RER

    RER Senior Member

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    Out of more DD mechanical inspections than I can remember I only recall one that included a compression check. Visual inspection of air boxes yes on all. In my experience the total cost is in the $2500 range.
  17. Capt J

    Capt J Senior Member

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    These are my feelings, if the bore scope looks good, and they turn WOT and start without smoking I wouldn't do a compression test on Detroits considering you can see into the liners from the inspection ports..... I just did a survey on 2-C32's including all of the samples and 2 generators and it cost $1800.......included EVERYTHING.
  18. Capt J

    Capt J Senior Member

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    I had this happen. A set of Covington 12v71's TI's, they used a 1.46" injector height for some unknown reason even though in the DD book for covingtons and those injectors it calls for 1.98". The buyer bought it and I continued on with him. It black smoked like crazy after this compression test (they set the injectors to 1.98) took the dealer 6 seatrials at lord knows the cost, I know my costs for running the boat and a mate......to figure out they take a generator injector height setting.
  19. Cruz

    Cruz Member

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    Compression testing has been scrapped knocking cost down by around $1500. Boat was last run in December without issue & has been on hard since. Great advice all around - thanks again.