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16-92 broken valve question

Discussion in 'Engines' started by Bamboo, Sep 11, 2012.

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  1. Bamboo

    Bamboo Senior Member

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    If you drop a valve by breaking the valve head and there is no visible damage to the piston or head otherwise do I need to buy a rebuilt head or can I have a new guide + valve installed and keep the head? No other damage is visible and the engine has less than 1000 hours SMO. Of course the turbo has damage- can I have the turbo cartridge replaced or do I need a "new" turbo?

    Attached Files:

  2. SHAZAM

    SHAZAM Senior Member

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    Both the head and turbo can be rebuilt. I just finished a similar repair to my 16's.
  3. Capt J

    Capt J Senior Member

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    You can have your existing turbo rebuilt and it shouldn't be a problem.

    Are you totally sure there is no damage to the cylinder walls or rings or anything? Sometimes everything will look perfect and a broken valve could've broken the top piston ring.

    Your existing head can be rebuilt, the valve/seat/and guide can be replaced. All of the valves don't look right on that cylinder compared to the other cylinder in the picture. You can see parts of the valve seat visible on the other 3 valves and it doesn't look like the valves are centered on the valve seats......which could be do to worn valve guides, loose seats, weak valve springs, High EGT's, detonation, or loose valve guides.....either way it doesn't look right......the cylinder next to it does in regards to valve seats, but not color. Have the fuel injector flow tested on that cylinder at the bare minimum.

    Was this a DD reliabilt head by any chance dating back to ohhhhh 2007 or 2008ish? At this point in time, and in your situation, I would rather have a good machine shop rebuild your head, than buying a DD reliabilt head.

    I take that back there is also something suspect flaking off of the lower valve on the cylinder next to it. Is that carbon or? Also the cylinder next to it and the first cylinder on the right, the valves don't look exactly right. It looks like they're running lean on fuel judging by the whiteness of some of the valves. The white dotting next to the left of the valves, on the cylinder directly next to the damaged one looks like a little detonation to me. I would check all injectors, reset the timing on the motor, and also check fuel pressure at the back of the rail once it's all put back together. What condition were your fuel filters in? Check fuel tank vents as well. Have the fuel tested as well, it's cheap to send a sample off (just like oil).
  4. Bamboo

    Bamboo Senior Member

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    I got a quote for around $1500 for a Reliabuilt head and $1400 for the turbo- why would I rebuild vs these prices? This head was from the early 2009 rebuild.

    I don't know if there is damage to the connecting rod- the piston top has no visual evidence of a valve hit.
    It seems there is a chance that the connecting rod may be bent even with the lack of visual marks on the piston. In that case it's a judgement call- but perhaps wise to change them now.

    The engine does run a bit lean to lessen visual exhaust smoke.
  5. chesapeake46

    chesapeake46 Senior Member

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    Bent Rod

    If you trun the engine to TDC on each cylinder, you'll know if you bent a rod beacuse even a small bend is noticable and measuable from the top of the cylinder wall to the top of the piston by using a straight edge.

    Tough luck, sorry for your heartache.
  6. RT46

    RT46 Senior Member

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    Bamboo,

    is that head from the Z 65?
  7. Capt J

    Capt J Senior Member

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    Because if you go with a reliabilt, you'll get the exact same quality head as what you have, and it will stay together for about as long, maybe less. I had a 12v71 TI rebuilt in 2008 with all reliabilt parts and the dealer doing the work......within 3 months and 130 hours smoh, the engine had to be majored again due to a split tip on a reliabilt injector and 5 others out of 12 were deemed bad (also 3 months old). It completely washed out a cylinder liner and 4 other lines had very strange wear marks/grooves and were replaced as well. The reliabilt head also had issues....... bent valve, broken seat etc........The quality on the reliabilt parts is not good in my opinion...... I've heard several stories.

    I highly doubt you'd have a connecting rod issue......especially without any piston issues and without dropping the valve.
  8. SHAZAM

    SHAZAM Senior Member

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    I'd always thought that reliabilt was the best. A few years back one of my friends pointed out that the same company that was building aftermarket parts for two cycle detroits was building all the parts supplied to detroit that were being relabeled as "reliabilt".

    Secondly, I'd much rather have a good shop rebuild the heads than have to take a chance on "reliabilt" parts. As far as there injectors go or for that matter any "new" injector, I always give them to an injection shop to be tested before they're installed. You'd be surprised how many "new" injectors are crap right out of the box.
  9. Capt J

    Capt J Senior Member

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    Reliabilt parts used to be the best......that was until MTU got involved. Now they're either rebuilt in Mexico or sourced from the cheapest vendor.....so I've heard.
  10. ArielM

    ArielM Senior Member

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    So who should we buy our parts from the next time any of us have to do a rebuild? I had heard from my parts dealer that Reliabuilt was getting better. That they had reorganized into new warehouses about 6 months ago and they were getting their act back together.

    How is Clevite parts? I just dont get why there is such a problem with detroit parts. There are hundreds of thousands of these engines still around so there is obviously a market for quality parts.
  11. Capt J

    Capt J Senior Member

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    MTU bought out Detroit Diesel for only one reason. The Detroit Diesel Engine Control......or DDEC electronics. MTU then took the engine software and DDEC system and mated it to all of their engines (MTU's), and stopped making 2 strokes in entirety. They see 2 strokes as old technology and a dinosaur. They want nothing to do with the 2 stroke, nor anything having to do with supporting them. They go with the cheapest supplier for hard parts for the 2 strokes, and the stuff that's rebuilt.....like cylinder heads and injectors are not of the quality they used to be. They offer a 6 month/250hour warranty on a major overhaul with their parts and their dealers......what does that say......
    I feel this way about their current engine models as well. I have seen so many accessory parts fail on their newer engines, both aftercoolers leaking on 1 year old 200 hour series 60's, a freshwater pump on a 16v2000, starter on a 10v2000, injector pumps on another 16v2000, etc etc......that I don't see with this frequency from other manufacturers. And these were all on low hour nearly new engines. Internal parts seem to last.

    They also had the first 150 sets of 16v2000's come apart because their supplier stamped the piston rings upside down. I know of 2 custom sportfish that had to have the entire boat torn apart to have the engines rebuilt less than a year old......back in 2004.

    To Admit Reliabilt parts are "getting better" means that they were bad before.....isn't that like Winn Dixie advertising, getting better everyday.....LOLOLOL......Federal Mogul is making cylinder kits/liners etc. for the 2 strokes and I would trust their products......I've heard good reports on their DD stuff.
  12. Marmot

    Marmot Senior Member

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    If the piston and liner don't show any signs of the piece of valve banging around then you are good to go with the rebuilt head and turbo cartridge.

    Capt J is correct in mentioning that the injectors need some attention, judging by the flame patterns. Check the piston crowns for signs of flame impingement as well.

    Detonation? C'mon J ... it's a diesel. There is a relationship between what you see on that head and "diesel knock" but it is subtle and may or may not have anything to do with the valve failure.
  13. Capt Ralph

    Capt Ralph Senior Member

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    Always, Always, Always, Always, have your new or rebuilt injectors POPd before installing them. Reliabuilt or Mom/Pop brand does not matter.
  14. Marmot

    Marmot Senior Member

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    BTW, forgot to mention it in my first response, that engine did not "drop a valve" or "swallow a valve." A small piece broke off and went out the exhaust.

    Most larger engines have a junk screen just before the turbo to catch bits of valves and debris so the turbo doesn't fall victim to a valve problem.

    If it had swallowed a valve you would have seen something like this:

    Attached Files:

  15. Capt J

    Capt J Senior Member

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    Speaking of which, I just had an owner buy an early 80's 55' Hatteras SF for around $100k with 12v71TI's and it has a complete set (24) of new injectors, not reliabilts on the boat in the ac boxes. Talk about finding gold.

    I agree with Marmot, if the liner shows no signs of scuff marks from the valve piece getting stuck between the piston and cylinder wall, and there's no dings on the piston top from bouncing around in the cylinder (which I doubt) because you'd see them on the head as well, then I don't think the motor recieved any damage other than what you already know.....

    Yank all of the injectors and have them rebuilt and flow tested.......

    I never remember having to replace injectors on DD's unless you ran them with plugged fuel filters or had a lot of water in the fuel. Back in the day, the injectors lasted and lasted. Now, with this reliabilt crap, it seems like people are having bad injectors pop up all of the time...... A large DD admitted to me one time that when they rebuilt their own injectors they used to never have issues with them......only one injector every once in a blue moon. He then went on to say that they have issues with reliabilts all of the time.......
  16. Jimbo1959

    Jimbo1959 Member

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    That valve is burned away. Check bridge adjustment and valve adjustment on the remaining cylinders. If no signs of damage to cylinder wall or piston, check piston height, if good rebuild head, replace turbo cartrige and be on your way. One last thing check injector tip protrusion.
  17. Capt Ralph

    Capt Ralph Senior Member

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    I keep going back to your original picture. That is a good looking head. I have been around a few failures like this before. Burnt & broke valves happen on them all.
    New guides, valves and seats should fix you rite up. Take your time in checking the rest of the head.
    Small mirrors will help in checking the piston top ring, piston and air port in case it bounced around before getting blown out. Usually it gets blown out immediately.
    Have that injector tip checked and all injectors from that head pop'd to insure uniform flow between them all.
    Depending on the damage to your turbo and overall condition, It may be easily repairable in stead of replacing the whole insert.
    Unlike the next picture where a valve did drop and killed a good head, good luck stayed and you should be motoring soon.

    Look forward to hear more news.
  18. Bamboo

    Bamboo Senior Member

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    All fixed now. Reliabuilt head and turbo and a sea trial today. Rebuilding added too much time to the repair so "new" stuff it was. Thanks for all the replies and comments.
  19. Capt Ralph

    Capt Ralph Senior Member

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    What (who's) injectors did you use?
  20. pprecourt

    pprecourt New Member

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    Goodmorning, had very similar situation on 12v92ta, 12hrs SMOH!
    My question is 2 part:
    1. what causes a valve to break (can I avoid it happening again?)
    2. If piston has some dings in it but absolutely no other visible damage to rings/ cylinder walls, can we just do head and and turbo and be on our way?
    Did check for bent rod, no problem there.
    thanks in advance for you help. you guys are AWESOME!