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Detroit diesel hole in the block, repairable?

Discussion in 'Engines' started by Matt46post, Oct 7, 2017.

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  1. Matt46post, Oct 7, 2017
    #1
    Matt46post

    Matt46post Senior Member

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    i am looking at boat that has
    12VA71TI engines in it, it seems one of the engines has thrown a rod thru the side of the block , the hole is behind the starter about 4" in diameter and it's a couple inches above the oil pain ,can this block be stitched welded usually or repaired ?the engine is a 1981 and has 1400 Original hours on it,what else should expect to replace when this happens to an engine other than a inframe kit , I am not sure if the owner ran it out of oil and or over heated it
  2. Capt J, Oct 7, 2017
    #2
    Capt J

    Capt J Senior Member

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    No, you cannot weld cast iron. I've seen people drill and tap and screw a plate over a hole in Detroit Diesels before......I would NEVER do this. Who knows, I'd suspect that everything is bad......overheating wouldn't throw a rod, that's usually an over-revving situation or just run WOT all of the time, or lack of oil. There should be enough 12v71's around you should be able to find a good one to rebuild.
  3. Capt Ralph, Oct 7, 2017
    #3
    Capt Ralph

    Capt Ralph Senior Member

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    Could be a sign the other engine has been abused also, just has not let go YET..
  4. Pascal, Oct 7, 2017
    #4
    Pascal

    Pascal Senior Member

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    Unless the price is low enough for a repower, i d run. Who knows how long the other engine will last...
  5. Capt Ralph, Oct 7, 2017
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    BTW, QSM11s are the replacement choice for 12V72Tis with down angle clutch.
    Been dreaming about it for years.

    Here Lotto, Lotto, Lotto...
  6. Capt J, Oct 7, 2017
    #6
    Capt J

    Capt J Senior Member

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    I'd rather replace them with C18's. hehehe
  7. Capt Ralph, Oct 7, 2017
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    C18s are a bit beyond 700 HP and the cost.
    But if I really did win the big (BIG) Lotto, I could go Cat.
    :)
  8. Ormond Bert54, Oct 8, 2017
    #8
    Ormond Bert54

    Ormond Bert54 Senior Member

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    I just replaced a block on one of my 12V71TI engines with a block from Diesel Pro Power. 888-433-4735
    dieselpro.com

    I needed a block and my mechanic shop Jacksonville Diesel Parts, Sales and Service said these folks are trustworthy. The block was $6k including shipping and was clean, checked and ready to go. They were easy to work with.

    What type of boat is it? The engine needs to come out obviously which is the only reasonable way to rebuild the hulking monster anyway.
  9. Capt Ralph, Oct 8, 2017
    #9
    Capt Ralph

    Capt Ralph Senior Member

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    What ever Steve says at Diesel Parts & Service Jax, is gospel.
    Been doing business with them for over 25 years.
    Henry ran the shop then and Steve was a round kid.
    If they can't help, they will point you in the best direction.

    They won't come to many little boats these days, but send the engines to them.
    Complete rebuild and a real dyno test and run time/HP log.
    I always enjoy visiting the shop and hearing the last engine screaming away in the run booth.

    When I win the big Lotto (any day now), I'll sell my perfect 12V71TIs cheap.

    Here Lotto, Lotto, Lotto...
    Last edited: Oct 8, 2017
  10. PacBlue, Oct 8, 2017
    #10
    PacBlue

    PacBlue Senior Member

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    What horsepower are the original 12V-71TI's that the OP is looking to repair/replace?
  11. Capt Ralph, Oct 8, 2017
    #11
    Capt Ralph

    Capt Ralph Senior Member

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    TIs usually stop at 650HP. Exotic injectors may offer a lil more.
    The after market marinizers leaned to the TAs for 900+
  12. Capt J, Oct 8, 2017
    #12
    Capt J

    Capt J Senior Member

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    I've seen many TI's around 735 hp.
  13. Matt46post, Oct 8, 2017
    #13
    Matt46post

    Matt46post Senior Member

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  14. Matt46post, Oct 8, 2017
    #14
    Matt46post

    Matt46post Senior Member

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    The engines are 12va71ti 650hp 1981 vintage, they have 145o hours on them ,the one engine runs great,defineatley doesn't need to be rebuilt, the current owner of 4 years never ran the boat much or serviced the engines or generators in the last four years,the boat has been used as a live aboard for the past 4 years ,I believe after being kicked out of a marina about 6 months ago he started the engines without checking any fluids and ran the boat and thru a rod , he probably hadn't had the bottom cleaned in a few years and there is a good chance the growth could of restricted water flow? .but there really isnt a person that knows exactly what happened ..actually looking at the block there seems to be 3 stacked threaded holes down the side of the block for mounting brackets every 6-8" inches ,That you could actually fabricate a cover plate and bolt it to the block to cover the hole if there isn't any other block damage, buying a rebuilt long block or just good replacement block really isn't an issue for me Detroit diesel parts are abundant and are not pricey, it's getting the engine out of the boat looks to be the real project and if doing an in frame and repairing the block is do-able it seems like such an easier and more cost effective way on an old hatteras that will probably spend the rest of its life as a live aboard that might cruise the sf bay a few times a year....I would assume to pull the engine you have to remove the galley or parts of it and lift the engine and pull it thru a side window or roll it thru the salon and out thru the aft deck? thanks for all the responses I really appreciate it
  15. Capt J, Oct 8, 2017
    #15
    Capt J

    Capt J Senior Member

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    It sounds to me like the threaded holes were installed for a cover plate because it threw a rod. The holes you're describing do not sound factory to me.
  16. Pascal, Oct 9, 2017
    #16
    Pascal

    Pascal Senior Member

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    If the boat sat with minial running and service for years, you have to assume the other engine isnt going to last long but you wont know until a proper sea trial is done and that means rebuilding the other engine.
  17. Capt Ralph, Oct 9, 2017
    #17
    Capt Ralph

    Capt Ralph Senior Member

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    Yes, there are mounting pads on the block sides. Usually hidden by the starter, oil cooler, oil pressure block (attached to these threads) and other items.
    A little raised from the cast. Not meant to accept any strength from the block, just hang junk on.

    If the rod really popped, the crank can not be trusted if it's still intact at all.

    It's a money hole and to avoid throwing cash at it twice, I'd replace the short block.

    Must be a heck of a deal knowing one engine is scrap and the other engine, although running, has no good history.
    What about the gen-set?
  18. Capt Ralph, Oct 9, 2017
    #18
    Capt Ralph

    Capt Ralph Senior Member

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    The 650 figures were shaft HP, around 675 - 680 flywheel with factory parasites.
    There were a few attempts (non factory) to tweak some more out of them (up to 750 flywheel HP) but the base TI package just could not deliver enough air.
    Instead of messing with the TI, marinizers went to the TA.
    With the TA, more cool air was available cheaper than after market. Now they had room to tinker with cam timing, injectors and turbos.
    These changes along with paint color, Detroit was glad to provide on the line.
    Other sites (Pan-Tropic) still luved to tinker them selves.

    That serial number is still so important and build history is still available from DDC.
    Factory horse power, IMO, is still the best tune on any Detroit block.
    Last edited: Oct 9, 2017
  19. Ormond Bert54, Oct 9, 2017
    #19
    Ormond Bert54

    Ormond Bert54 Senior Member

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    My 12V71TI's produce 860hp on the dyno. The turbo's are: Part Number R5101513 and the injectors are: Part Number R5229715 (9215 Injector). My engines were originally marinized by Key Power but there were others. The engines started out typically at 650hp but were increased to 800 or 850 by using larger turbos and injectors.
  20. Capt Ralph, Oct 9, 2017
    #20
    Capt Ralph

    Capt Ralph Senior Member

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    FM does happen. The 921X injectors are exotic in the TIs.
    Larger turbos were limited in the non-water claded models. Cool if you had water cooled turbos.
    Dyno 860 would be a fat 835 hp plus at the shaft. Still an impressive beast.
    Forgot to mention, the 900 hp TAs has free spooling blowers when turbo pressure over pressured them.
    No room for a by-pass system like the straight 671TIBs.
    Maybe Key Power used these blowers also.
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