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I think I broke my engine

Discussion in 'Early CJ5 and CJ6 Tech' started by Stout, Aug 16, 2012.

  1. Aug 16, 2012
    Stout

    Stout Member

    Quakertown, PA
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    Nov 1, 2010
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    After successfully putting 150 miles on the Jeep after the rebuild, I decided to get brave and stray farther from the house. I took it for a long drive and as I was crusing at 45 MPH, I started to hear a sound that I first thought sounded like an exhaust manifold leak. Happened to glance down and noticed that the oil pressure gauge was reading half of what it typically does at high RPM, about 20 whereas it usually is up to around 40. Pushed the clutch in and the gauge dropped to zero.

    Pulled over and shut it off. After it sat for about an hour, I could start it up and get decent oil pressure. But now I have a knock. Can't yet tell if it is valve train or worse. Still not getting full oil pressure.

    What the heck could have happened and how do I tell if I hurt the engine? Oil looks nice and clean. Antifreeze is clean. No smoke from the tailpipe as far as I can tell.
     
  2. Aug 16, 2012
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    A "knock" is almost always a connecting rod bearing, the biggest indicator here is the sudden drop in oil pressure. If you can't find a significant oil leak, i think I woudl want to drop the oil pan and pull one rod cap at a time to look for excessive wear or "wiping" of the rod bearings. Sometimes you can just wiggle the rod caps while they are still bolted on and you will feel play in them. If there is any play that you can feel, the bearing is usually bad.
     
  3. Aug 16, 2012
    Stout

    Stout Member

    Quakertown, PA
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    So did the bearing cause the drop in oil pressure or the other way around?

    If it is just a bearing, that's not a huge deal and that can be replaced without pulling the motor, correct? Or should I pull the motor and plan on a complete rebuild (again)?
     
  4. Aug 16, 2012
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    After I rebuilt Wimpy's 4 cyl, I forgot to torque 2 of the rods down. It loosened up completly and tossed the rod. Luckily it was idling down about 200 rpm and just bent a rod. Easy enough to replace.

    Low clunk usually bottom end like steve said. Higher pitch ticking is usually top end valve train.
     
  5. Aug 16, 2012
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    maybe spun a bearing and now the oil passage hole is blocked?
     
  6. Aug 16, 2012
    Stout

    Stout Member

    Quakertown, PA
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    It sounds to the naked ear like upper valve train but when I put a stethoscope (sp?) on the side block valve cover I can hear grinding toward the front. So I do believe I have a bearing problem.

    I have a weepy RMS anyway (stupid rope seal) so maybe I should just pull the crank out of the bottom (I can do this without pulling the motor, correct?) and replace the bearings and RMS...?
     
  7. Aug 16, 2012
    58 willys

    58 willys Sponsor

    Millsboro, Delaware
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    Sorry to hear this Chris maybe get lucky an nothing major. If your pulling the crank out your going to either have to remove the engine or drop the the trans & bell housing
     
  8. Aug 16, 2012
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    I think I would pull the pan for a looksee, and evaluate before making any assumptions. You can pull the pan and the head, and pop one or more rod/piston units out pretty easily with the block in the jeep. Pulling and reinstalling the crankshaft will involve dropping the transmission/transfer case and then the bell housing and flywheel. If it comes down to that it is prolly much easier to pull the engine and put it on a stand so you can flip it over. Like Brian said, a concern is how much debris ended up in the oil passage in the crank.

    My story was stupidly checking the main bearing sizes and not the rod bearing size. Turns out the mains were standard size but the rod journals were .020 undersize so it hammered the crap out of the std. sized rod bearings I put in it. Next to zero oil pressure and it sounded like a diesel when it fired over. But hey, I was 17 at the time and this was my first full rebuild! :oops:
     
  9. Aug 16, 2012
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    with the engine running and knocking, remove the spark plug wires one at a time; usually the knocking or bad cylinder will be discovered by the knock going away when the wire is removed.
    If the crankshaft needs removal, engine removal is easiest way in my opinion.
     
  10. Aug 16, 2012
    Stout

    Stout Member

    Quakertown, PA
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    Hey guys, as usual I appreciate the help in my time of need. Not saying I didn't make any mistakes, but I was extremely careful when I assembled the engine and I'm convinced I torqued everything properly. I'm pretty OCD about that sort of stuff and I checked it many times before buttoning everything up. I used plastigauge to check the bearing clearances and everything was to spec. So it just puzzles and upsets me that this could happen.

    But I was considering pulling the trans/bellhousing and lowering the crank to replace the RMS anyway.
     
  11. Aug 17, 2012
    Stout

    Stout Member

    Quakertown, PA
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    I may go ahead and pull the motor out so I can put it on the stand and inspect the bearings and fix the RMS. When I pulled the motor before, I already had the body and front clip off so it was pretty easy. Any tips or things to watch out for when pulling it with the front clip in tact? I assume I need to pull the radiator, no?
     
  12. Aug 17, 2012
    1955CJ-5

    1955CJ-5 Member

    Boise, Idaho
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    Sorry about your engine, but I'm sure you will get it sorted out.

    I considered pulling the engine on my '55, and may still do it before painting. I would think you would certainly need to pull the radiator, and I would pull the front grill assembly, and probably the fenders. It's not that tough for the access gained.

    Hope my jeep will look as nice as yours someday!

    Randy
     
  13. Aug 17, 2012
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    Sorry to hear Chris. Before painting my jeep and putting the body on, I drove mine all around with just the frame. I found a few issues that way. I know, shoulda, coulda woulda. I think you should pull the pan and you might find it is something really easy to fix. I know if I pulled the engine in my '53 and found it was something stupidly easy to fix, I would be really mad. I'm glad to hear you shut it down quickly after noticing something was wrong and saved yourself from major damage.
     
  14. Aug 17, 2012
    Stout

    Stout Member

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    I was hoping to not have to pull the front clip if possible. It took me a long time to get the fenders and grille centered and positioned correctly. Pulling the motor is easy compared to doing all that again. I have a good engine hoist with a balancer so I'm hoping to just pull the radiator and carefully manipulate it out of the engine compartment.

    If I didn't want to replace the rear main seal, I would probably just remove the pan and have a look-see but since I'm going to do that anyway, I guess pulling the engine out is the right thing to do.
     
    Last edited: Aug 17, 2012
  15. Aug 17, 2012
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    Do as jpflat2a sez and determine which cylinder the knock is in first. This will let you know where to really look when you open the bottom of the engine.
     
  16. Aug 17, 2012
    Stout

    Stout Member

    Quakertown, PA
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    OK I'll do that tonight. When I put the stethoscope on it last night, the front of the block sounded bad so I would bet it is the number one rod bearing. It still baffles me how everything was working so wonderfully and then boom. Weird.
     
  17. Aug 17, 2012
    deputyvaughn

    deputyvaughn Member

    North Alabama
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    If I had to guess, you'll have a rod or main bearing issue....Chances are that either will require the crank to be removed and repaired or replaced.

    Scott
     
  18. Aug 17, 2012
    1955CJ-5

    1955CJ-5 Member

    Boise, Idaho
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    The trouble you had with aligning the front clip got me looking at my jeep....I recently replaced the body-to-frame isolating pads, and that changed it from a slight tilt to the drivers side to a slight tilt to the passenger side.

    While I had all the body/frame bolts loose it seemed that it would be possible to accidently shift the body tub on the frame....if it wasn't exactly straight, with the sides parallel to the frame rails, that would mess up the alignment of the front clip..... That may be what I did as I first jacked up one side and replaced the pads and then did the passenger side and the rear....more food for thought...

    By the way the new pads made a huge difference as many of the body to frame fastening points were just steel to steel with a loose bolt!
     
    Last edited: Aug 17, 2012
  19. Aug 17, 2012
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    It is do-able by pulling just the rad, but it is much easier if you pull the grille shell also. I know you went through a lot to get it all lined up with the new tub and such, but you don't want to bang up the paint on the grille shell either!
     
  20. Aug 17, 2012
    Stout

    Stout Member

    Quakertown, PA
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    Yes good point.
     
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