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Thread: Universal Diesel Mechanical Inspection

  1. #1
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    Universal Diesel Mechanical Inspection

    Hello,
    I'm looking at buying a boat with an inboard Universal Diesel and would like to get a mechanic to look at it. The person I was recommended said that he doesn't have the adapters to do a compression test on it. Is this a necessary part of a mechanical inspection on a motor like this? The mechanic said that you can usually tell a lot from a leak down test so compression is not really necessary.

    The motor only has 1600 hrs on it and it looks very clean.

    Thanks

  2. #2
    1984 Ericson 30+, Nanaimo, BC
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    Hi,
    I'm not a mechanic, but I've owned our E30+ for 12 years and do most of the simple repairs and maintenance myself. If everything else checks out well, the oil looks good, no leaks of any kind, engine starts well, no blue or black smoke when you run the engine, then given the low hours I would be ok without a compression check. It would help if the owner has a maintenance log showing regular oil changes, filter replacement and similar maintenance.
    Good luck on finalizing your purchase!
    Frank

  3. #3
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    Leak Down VS Compression Test

    A compression test and a leak down are little different, but both can point you in the direction of failure. The compression test is a simple form of a leak down. Compression test will tell you if the cylinder pressure is within spec or not. The leak down will show in more detail where the leakage in the engine is...For example, if #2 cylinder shows leakage past what is considered in spec, you can determine where the failure is...if you pull the radiator cap off and you see bubbles in the coolant, you know the leakage is possibly from a head gasket. If you put your ear or hand over the air intake and feel air coming out, you most likely have an intake valve that is not sealing. If you pull the dipstick out and feel air coming from the hole, then you have piston rings that are not sealing......Usually the compression test is done first and if the cylinder pressure is within spec, Good to go!...If not, then one would usually do a leak down test to find where the problem may be...both test require pulling the injectors and installing an airline adapter to complete the tests. Also, for the leak down test, you have to turn the engine over by hand to test each cylinder at TDC (top dead center) compression stroke.....But to answer your question, if it were me, I would always do a compression test.
    Last edited by Baslin; 03-12-2018 at 03:35 PM.
    Josephine, E381 hull 505 (1983) Universal 5432

  4. #4
    Sustaining Partner Dave N's Avatar
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    If the guy can't do a compression test I'd look for a different guy, IMO. We had a separate engine survey done by a mechanic on our last purchase. The engine has 2500 hours. He found a number of things and missed a number of things. None of which were picked up by the regular boat surveyor. The compression was off a bit in 2 of the four cylinders. We had the seller cover half and took care of all issues. Runs great now.

    This was our seventh boat purchase. We had never had an engine survey on any of the others. I think it is money well spent.
    1985 Sabre 38 C/B
    hull #80
    Sturgeon Bay, Wi.

  5. #5
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    Thanks for the responses guys. The thing is that the mechanic who isint able to do the compression check is local and very reasonably priced-he just doesnt have the adaptor to do a compression check on a Universal. If I do want a compression check done I am going to be paying 3-4x more to get a mechanic from somewhere else to come and do an inspection. Sounds like best practice is to get the compression check done but most likely a leak down test would show if anything was up with the motor so I am probably safe to go without needing the compression test.

  6. #6
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    get an adopter

    hi

    perhaps you can purchase the adopter that's needed for s reasonable price. maybe someone on the forum can give you what you need to purchase. I don't have a diesel engine so I can't help. I saw a complete diesel compression kit on amazon for 30 bucks... how much is your peace of mind worth ? I know mine was worth a lot in the past..

    I hope this helped

    greg
    GREG
    s/v dalliance
    74 35II # 325
    wilmington,ca

  7. #7
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    Unless you have a really worn engine, I feel a leak down test without a compression test first is pretty subjective and potentially misleading. Here's why. All engines will pass air and you will hear/feel some level of air at intake and exhaust. If you have a blown head gasket, yes, you'd get air bubbles in the coolant, but at that point, you probably have a chocolate milk shake in your crank case oil anyway. You really need that compression test to tell you what the cylinder is doing and then the leak down test follows up to help identify the culprit, and at that point, you're more looking for whether it's just a valve job/top end versus the bottom end e.g. if you're not making good compression and there isn't much air coming from your dipstick, but intake/exhaust is roaring away, then you know you probably have top end issues. If intake and exhaust seem OK and the crankcase is actively hissing, then rings, but the problem is go do this on a good engine, and you'll hear noise at all check points, so you really need to know what that baseline is from the compression test to make heads or tails out of the leak down test. Just my opinion, and worth what you paid for it.
    -David
    Independence 31
    Emerald

  8. #8
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    Makes sense to me. I'm gonna pay the extra money and get a full inspection with a compression test. Might as well cover all my bases as peace of mind is worth the extra &. Thanks again guys

  9. #9
    Contributing Partner kiwisailor's Avatar
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    Engine Oil Lab Test

    When I had my E38 boat surveyed he also offered to have a 3rd party lab do an engine oil test. The test looks for contaminants in the oil and metal-to-metal engine wear. He took a small sample of engine oil and sent it off to the lab to be tested. I received the lab report back with a "no action required." Subset of report is below.

    IMHO I would suggest a oil sample test and forget about the compression test.

    Name:  Oil Test.png
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    Sherene & Mike Taniwha

    1981 E38 "KIWI"
    Hull #53
    Groton, CT

  10. #10
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    Buying a new boat -survey and mechanic inspection?

    Hi,
    I'm looking at buying a sailboat with an inboard diesel. Is it common practice to get the survey first and then if the surveyor says that anything mechanical comes up then get a mechanical inspection at that point? Or should I be getting a survey and a mechanical inspection from a marine mechanic no matter what?

    Thanks

  11. #11
    Advanced Beginner bgary's Avatar
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    Quote Originally Posted by Sailing11 View Post
    I'm looking at buying a sailboat with an inboard diesel. Is it common practice to get the survey first and then if the surveyor says that anything mechanical comes up then get a mechanical inspection at that point? Or should I be getting a survey and a mechanical inspection from a marine mechanic no matter what?
    Two different questions:

    Should you get a survey and/or a mechanical inspection? Up to you. What's your tolerance for risk? How skilled are you at identifying potential issues? How mechanical are you? Many people have the knowledge and experience to inspect a boat and make their own evaluation of condition and work needed. In my case, I wanted a "no surprises" purchase, and I know virtually nothing about diesel engines, so I did both the full survey and the mechanical. It was not a huge expense (~3% of the purchase price), at the very least it gives you a list of things to pay attention to, at most it can help you decide to walk away from a boat with major problems.

    As far as sequence? Probably depends on the surveyor. In my case, the surveyor wanted to have the mechanical done first so that he could review any mechanical findings before doing the full-boat survey.

    $.02
    Bruce
    "Makana" (ex-Thelonious)
    1985 Ericson 32-III #604
    Makana blog: here

  12. #12
    Moderator Christian Williams's Avatar
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    I think it was $250 for a well recommended diesel mechanic to spend two hours looking over the four-cylinder engine on Thelonious II.

    No compression check or send-out testing. But a veteran can tell a lot about how an engine sounds, drips, gurgles and starts by observation. He also examines the alternator and its wiring and the fuel filtration system. From evidence of maintenance, neatness and engine hours he makes assumptions and recommendations from experience.

    Not every mechanic is a teacher, so it is worth asking around to find such a one. They will be at beck and call while you own the boat, and it is very good to have a relationship,* somebody who knows you and will answer on the Fourth of July.

    Money well spent.

    *A friend overheard the following exchange:

    MAN #1
    (laughs)
    You two guys have a pretty good relationship going there.

    MAN #2
    We've been friends a long time.
    (beat)
    But we don't have a relationship.
    Thelonious II, E381 hull 513 (1984) Universal 5432
    Table of Contents for Thelonious Blog here
    Videos: http://www.youtube.com/c/ChristianWilliamsYachting

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