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Rebuild vs Repower

Discussion in 'Technical Discussion' started by ntavila, Jun 6, 2012.

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  1. ntavila

    ntavila New Member

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    Hi All,

    I posted recently looking for a mechanic because one of my J&T (based on DD) 6-71TIBs overheated and now needs a rebuild. I've been pricing out mechanics and of course it's not cheap. But I talked to a guy today who says he has a rebuilt engine that he would be willing to swap out for about the same as folks are charging me to rebuild mine. He runs a charter and says he no longer has a need for this engine. Any downsides of doing a swap that I should keep in mind? And what are the pitfalls of doing so. Once again, really appreciate the information.
  2. dennismc

    dennismc Senior Member

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    Ask for all bills and invoices and then have a mechanic check out the rebuild.
  3. K1W1

    K1W1 Senior Member

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    That is good advice.

    You will also need to make sure it turns the same way as yours.
  4. jhall767

    jhall767 Senior Member

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    I have the same engines so I'm very interested in this topic.

    Why is his rebuilt engine the same cost as having someone rebuild yours? Who rebuilt it? Is it a total rebuild? Receipts? Will it have the same warranty? Who will install/troubleshoot it?

    He has an extra engine and it seems like you are helping him out. Shouldn't his engine be cheaper? What will you do with your old engine afterwards?

    What about things like the transmission cooler, fuel cooler and heat exchanger? Which engine will they come off of?

    Have you priced out J&T's rebuilt engines? Supposedly they'll sell you a rebuilt engine with their warranty at a relatively good price.

    Finally I have (dread) to ask what is the cost you are being quoted? Not looking forward to paying for one of these myself.

    Thanks

    John
  5. Capt J

    Capt J Senior Member

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    If it's a twin engine application I would absolutely rebuild yours. 6-71's came in several different HP applications and of course J+T's made the most power. So unless you know what this rebuild engine is, chances are it's not the same engine/hp. Also, how long ago was this rebuilt engine rebuilt, and who did the work. Detroit Diesel only offers a 6 month warranty on parts.........so if the engine you buy comes apart at 20 hours, your SOL.
  6. ntavila

    ntavila New Member

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    Thank for all the replies. Very good advice.

    My understanding is he runs a fleet and used to have spare engines for each boat. I didn't ask whether he sold the boat for which is was a spare or what. Really, I didn't delve into the details about where it came from because I wanted to make sure it matched mine first. I have to go get the specs so that we can compare injectors etc.

    He has a shop for his fleet and my impression is that he did the rebuild. I will ask about this when we talk again. I understand it was a full rebuild and he suggests rebuilding mine so that I can keep it as a spare. Not really sure I'll take him up on that, but worse case scenario I could part it out.

    On the install, he would help me do it. We haven't discussed warranty yet.

    This is my first boat so I don't know what engines go for. My research is finding that the new engines are just slightly more than a rebuild. In this case for an inframe rebuild I've been quoted from 17K to 32K depending on the shop. The one he is willing to sell he says would be 18K. John if you want to know which prices go with which shops in town, PM me and I'll share.

    Additionally, I was wondering if anyone know how hard it is to get an old engine out and a new one in on a 38' viking. I was looking at it and it looks near impossible without tearing out the back of the salon. Something I am not excited about doing. The interior was redone in 06 and it looks really nice. I'd hate to mess it up.

    Thanks again for all the advice.
  7. C4ENG

    C4ENG Senior Member

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    In yachting those trying to save money always lose money. Those focusing on spending wisely always come ahead.

    If you try and purchase a motor (used or new) from a major known motor manufacturer or dealer you will find they do not like to stock motors on the shelf and they are mostly built to order. This is because motors laying around can develop internal issues with corrosion or moisture and other problems. The reputable company's do not want to deal with those potetional hazards and sell those liabilities to there customers.

    I would only buy that used motor from the man with the fleet if I was planning on rebuilding that motor and making sure it was suitable for the expense of installation. So if a motor needs to get rebuilt it might as well be yours that you already own. I very much agree with Capt J's statements.

    Get three quotes and get'er done. And then invite me fishing :)
  8. utspak

    utspak New Member

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    I was reading this thread and wanted to ask a question of all you 6-71TIB owners. Any of you familiar with Capitol Transmissions model 11-200? I am looking at purchasing a vessel with these and am quite concerned because parts are scarce as well as mechanics. I am looking into new transmissions, like ZF.

    Any comments or thoughts are appreciated. What new transmissions would be best or has anyone every done this?

    Thanks
    Stuart
  9. dsharp

    dsharp Senior Member

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    The only way to go with a full rebuild is from a large dealer that has the financial ability to stand behind the rebuild. A rebuilt engine can mean anything. My dad was owned boat yards forever and I spent more years than I care to remember following him around. None of that is really important but I have seen this situation end badly more times than I've seen the owner save money. Pulling the engine is no big deal. Just take the time to put paneling or heavy cardboard on the floor and walls. The yard should have a stinger bar made up and it takes about an hour to drop the straps on the travel lift and switch over. A 671 is relatively narrow, you may have to remove the exhaust to get it through the door. Only way to know is take a tape measure. Not to be rude but I've never seen a charter company with the funds to keep spare rebuilds that were anything I'd be interested in using. I'm sure there are exceptions.
  10. jhall767

    jhall767 Senior Member

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    If you have to tear out the back wall of the salon then your most economical avenue may be an in-place rebuild. Most likely they'll still have to lift the engine but only far enough to drop the oil pan.

    It's very common on these engines to do a top end only rebuild (pistons, liners and head) because the lower end usually lasts much longer. This may be an option for you and an issue of concern about the "already rebuilt" engine. Many charter boats overwork the engines and will commonly only check the lower end and replace the top end on these engines. That "deal" would have to be real special on price and from somebody I know real well. Too many things that can go wrong.
  11. ntavila

    ntavila New Member

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    Once again thanks to everyone for the input. After thinking it through and weighing out both options, I think I'll rebuild the one I have. If boats are anything like trucks, I'll save my self the headache of fine tuning the new engine until it runs like the replaced one did. For some reason there always seems to be quirks with the trany, or the motor mounts are just slight off, etc.

    Now I guess I have no choice but to do the most common thing I do with my boat . . . break out the check book :mad:

    Thanks again
  12. RT46

    RT46 Senior Member

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    shop around and get estimates and recommendations.

    Those are great engines that can last a long long time if well cared for and they dont require a someone with a PHD or computer science and engineering degree to change the oil.

    be advided that an in-frame rebuild can mean everything from changing one or two kits to the full monte:
    kits, rebuilt heads, mic-ed rolled in bearings, turbo, blower, injectors, cooling system.....

    get written and signed estimates of work to be performed and parts to be used replaced or rebuilt.
  13. Ormond Bert54

    Ormond Bert54 Senior Member

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    Getting the engine out of your boat to overhaul it on the stand isn't as bad as it seems. If you could find other owners who have had overhauls from the facility you intend to use, that would be very helpful.

    I had an in frame overhaul done in Orange Beach and it failed immediately. $65k down the tube. Suing those crooks for what it's worth.

    Ultimately, the pro who got me going by overhauling the engine again was John Carey from Carey's Diesel in Leipsic DE. He was excellent. That is not in your area but I'm sharing my experience to be helpful.

    The Guarantee from most might as well be written on a piece of toilet paper.
  14. dennismc

    dennismc Senior Member

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    Safest bet is get one of the original mfr's dealers to do the rebuild.
  15. dsharp

    dsharp Senior Member

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    How many hours are on the engine? I lost the water on a 6-71 while fishing and when I checked my gauges it was pegged. It cracked the head and cooked some of the seals between the head and the block. We put a new head on and it has run fine for years. I personally wouldn't try to rebuild it in the boat. A mechanic with a helper should be able to get that engine out in 4-5 hours. A shop that can run it on a dyno or a test stand at the very least would be desirable.
  16. Ormond Bert54

    Ormond Bert54 Senior Member

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    Yes ... my second time around, the engine was removed and built on the stand in the shop. It's just so much nicer that way. The completed engine went right in through the back window.
  17. Capt J

    Capt J Senior Member

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    I agree that it is more preferable to rebuild the engine outside of the boat. It's easier to get all of your torque specs perfect on rod bolts and main bolts, easier to assure all of the bearings are in place, and just a lot better working conditions to be meticulous. But, It adds a lot of labor to remove and re-install the engine (if it's even possible without cutting a big hole in some boats), versus doing an in-frame rebuild. If the engine got very hot, chances are the bores will need to be line bored and are probably out of round and egg shaped and the deck might have to be milled. A lot of DD bores weren't exactly true to start with. I had a guy that owned a machine shop that used to build race engines, he had a dedicated room that was a/c'ed and totally enclosed from the rest of the shop, just for building engines and he kept the floors/walls/work benches meticulously clean and would basically lock the sliding glass door, turn on the radio, and work without any interruptions.

    That being said, I have seen LOTS of engines rebuilt in place and have then lived a very successful life without any issues. OTO, I've seen 1 last 4 months and under 150 hours, due to a (reliabilt) bad injector that washed a liner out......and 4 other injectors on their way out. This was a few years back and DD tried their best not to cover it under warranty and only covered most of the expense. Even though it was done by a DD dealer and within 6 months.
  18. Bamboo

    Bamboo Senior Member

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    Pulling the engine to rebuild it is adding more complexity to the job than it needs. Pulling the salon apart and removing the salon back window to rebuild instead of in frame is a decision you'll have to make, I'd have it rebuilt as she sits unless you get several other opinions from shops which say it's better to pull the engine. Some shops will have the experience to pull and some will not. It's not rocket science to rebuild a 6-71 in frame and since you really do not have the full details about the other already rebuilt engine I'd stick with rebuilding yours.
  19. Capt Ralph

    Capt Ralph Senior Member

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    We rebuilt our 12v71ti in frame. It's the crank that may be the big factor. Drop the pan and pull a rod and main cap. If you can find anybody who remembers how to use Plastic-Gage, and in specs AND they can see a good even surface, do an in frame and save bux. These ole 71s usually need cylinder kits as needed and head/injector work.
    71s rule.
  20. ntavila

    ntavila New Member

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    Thanks everyone for all the replies. I found a guy that seems trustworthy and he seems to know what he is doing. Been around for 15 years and specializes in Detroits. He's starting the the job this week in frame. Just seemed easier. The good news is that after some further inspection it could be just busted seals and the head may be ok. Won't know until the machine shop tells us.

    But now I'm off into a new section of questions. He's quoted me all detroit original parts but also said that some of his customers have used Federal Mogul aftermarket parts. He said he normally works with Detroit originals but has been really impressed with Federl Mogul. Anyone have any experience with Federal Mogul?