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Thread: Bad squeaky sound, probably bent crank (3.0L)

  1. #21
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    Quote Originally Posted by David T View Post
    If the motor has not actually run you may only have damaged the bearings. Examine the crank and cylinders and you should be OK with new main and con rod bearings. Of course you must figure out why the oil pump isn't pumping oil. When you removed the oil did you measure how much came out?
    I admit I assumed that I wasn't going to be able to find bearings for this engine and would just have to replace the whole thing (gaskets are easy to find, though), but a quick check of NAPA's site showed that they are indeed available (~$90 for the set of main bearings, and ~$8 for each con rod bearing), so that's good news. That will save a lot of trouble over having to get a new motor. I want to get this deflection issue sorted before I replace the bearings, though. And as you said, this is all moot if the oil pump doesn't work, so I'll be taking that out once the deflection is solved.

    I didn't measure the amount of oil, but I still have it all in the pan that I drained it into. I'm betting it's all the oil in the system. There's a picture of that oil in another post, which is mostly filling an 8 qt pan. I can empty it into bottles to test it (or maybe I can measure it with a scale...).

    Thanks!

    -- Joe

  2. #22
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    Quote Originally Posted by dn010 View Post
    Take the pump out and see if there is an issue with the gears or relief, if the spring is broken, etc. Run some oil passage cleaners through. Take the valve covers off and look at the camshafts, rotate the engine to look at the cylinders and piston skirts from the bottom. Get new bearings if everything looks good and put it back together, as said I doubt youíve trashed the engine. It looked like you only just Ďwipedí the bearings.
    I'm thinking you're right that this engine can be saved. I saw that I can get a new oil pump at NAPA for about $140 or so, or a rebuild kit for $40, so I'll probably do the rebuild. My friend and I will be sure to go over everything as you describe it. Thanks!

    -- Joe

  3. #23
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    Quote Originally Posted by DMC5180 View Post
    The 3.0 did not use the spacer. But 2.8 does and needs it for the deeper pan. Glad you verified it was installed. That means itís still a head scratcher as to why you didnít have any oil pressure. Makes one wonder if there was blockage in the pickup circuit or a missing or worn-out component within the pump assembly. I wonder if the pressure relief valve is functioning properly. If, it was missing a component it may never build pressure.
    We had intended to poor oil into the pump today and then crank the engine and watch it spray everywhere (or do nothing), but the flex plate deflection occupied our time. Once we have the timing cover off we'll check all the passages for blockages, and check the pump itself. Thanks!

    I did take apart the 2.8L pump (mostly I was using the old engine to get a better understanding of how everything works by disassembling the whole thing), but I don't think I took apart the 3.0L. Which at least means that I don't think _I_ broke it. .

    -- Joe

  4. #24
    EFI'd dn010's Avatar
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    Bad squeaky sound, probably bent crank (3.0L)

    The original 2.8 and 3.0 pumps are different, they cannot be interchanged unfortunately. Majority of the pumps Iíve taken apart had damaged relief springs.


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    -----Dan B.

  5. #25
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    Quote Originally Posted by dn010 View Post
    I have two cranks if you need one...
    Sweet -- I may well take you up on that. I get the impression that there is no practical way for me to tell if the crank is really bent/damaged without taking it a machine shop. If I've ruled out all the other possible reasons that the flex plate is wobbling, it seems I may have to resort to replacing the crank.

    Thanks!

    -- Joe

  6. #26
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    Quote Originally Posted by dn010 View Post
    The original 2.8 and 3.0 pumps are different, they cannot be interchanged.
    Good to know. I disassembled the 2.8L pump to learn; I don't think I actually have it anymore. I mostly don't recall if I took the 3.0L one apart; I don't think there was any need to, so I don't think I did. But that just means that it might have always been broken.

    -- Joe

  7. #27
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    One last thing -- it'll be 3 weeks before I can do anything on this again (out next week, easter weekend trip the next week). Then I'll do the dial indicator test on the hub, and then we'll likely remove the timing cover and test the oil pump.

    Thanks again for the help everyone!

    -- Joe

  8. #28
    Administrator Ron's Avatar
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    Quote Originally Posted by jangell View Post

    There are also gouges on the few main bearings that we removed.

    Attachment 55680
    Does the main journal mated to the bearing pictured above have scars on one edge only like this bearing?
    If so, is the crank scared all the way around?

    Bad pump/lubrication or not, it looks REALLY dry...

  9. #29
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    Quote Originally Posted by Ron View Post
    Does the main journal mated to the bearing pictured above have scars on one edge only like this bearing?
    If so, is the crank scared all the way around?
    So far it looks like only the bearings were damaged, and the itself crank doesn't have any marks, but we didn't check the other side, so we're not totally sure about the other side yet. That particular bearing was the worst of them, if I remember correctly. My friend thought it looked like the damage was only to be bearings (he was doing most of the work here, as he knows a lot more about engines than I).

    My friend says: "The front one had that marking on it, but I was able to start scratching it off with my fingernail so it wasn't impregnated into the metal itself -- it was just right at that the material from the bearing was rubbing off on it, but if it had gone any longer it would've started digging into the metal so we got it before damaged it." Said friend is a classic car mechanic, but not specifically a DeLorean mechanic (he's more of an Alfa Romeo guy).

    I'll get pictures of all the bearings and the crank next time we take it apart (so, in about 3 weeks).

    Bad pump/lubrication or not, it looks REALLY dry...
    That's an understatement -- even in person, it looks like it never had oil in it, even though the pan was full. Definitely looks like a pump failure. I think it was almost two years since I put oil in it, and then it sat for quite a while as I figured out what to do about an exhaust, and installed the new fuel system and electrical, which I guess was plenty of time for all the oil to drain into the pan.

    Thanks!

    -- Joe

  10. #30
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    I'm assuming you didn't see if there was any pressure on the gauge while cranking the engine? My bet would be the pump's pressure relief spring is broken and the valve is stuck open. There is really nothing else that can go wrong with the pump, unless you have clogged passages. The pump is basically just two gears and then the valve. Luckily, you CAN use the spring from the 2.8 if the 3.0 spring is indeed broken, as long as the 2.8 spring isn't broken as well.

    Check it out next time you see the engine. Good luck!
    -----Dan B.

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