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Bent push rods!

Discussion in 'Early CJ5 and CJ6 Tech' started by Buddha44, Jun 5, 2014.

  1. Jun 5, 2014
    Buddha44

    Buddha44 Member

    San Clemente, CA
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    May 18, 2014
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    Ok, some of you shave been following my "simple" project so I won't repeat myself.
    In removing valve covers and intake tonight, just so I can change gaskets, degrease, paint etc. and clean up engine compartment, I un-covered some bent pushrods. Ouch.
    How and why do you think this happened? I recently purchased jeep and no little of the jeeps past.
    I do know it was neglected, and I do know someone had pulled oil pan and intake before. Valve covers never been off til tonight. When I removed oil pan about a week ago I found hard plastic chunks in bottom of pan. A fellow jeeper on this site suggested they might be chewed up timing gear since original was nylon.
    That's about all I know.
    Can I get out of this with just new pushrods?
    What do you think happened? What usually causes bent pushrods?
    Any suggestions/comments on how, why, installation tips, etc., greatly appreciated.
    Motor is in the jeep.
    Thanks!
     
  2. Jun 5, 2014
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Over revving the engine frequently results in bent push rods.
     
  3. Jun 5, 2014
    tarry99

    tarry99 Member

    Northern California
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    Buddha,

    I have been following this quite closely and have watched all your going through with all the dirt and garbage inside that motor.........Obviously you know already that motor is shot.......You may cobble this back together but its doubtful that it will last very long especially if you put allot of miles on it at higher RPM's like driving at 40-50 MPH...........Bent Push rods as Nick mentioned could be from over revving ........but more than likely from hydraulic lifters that are so gummed up and dirty inside that now act as solid lifters with no clearance...........the cam may now also be doubtful at the lobes where the bent push rods came from and if you have not pulled that timing cover off yet you probably need to look at the timing gears and chain up front.............and see if that's where all the plastic came from that's in your pan..........The rocker arms are another component that dislike running in Mud! and will seize up!......Not trying to discourage you, but these things have a way of going down hill fast.
     
  4. Jun 5, 2014
    Buddha44

    Buddha44 Member

    San Clemente, CA
    Joined:
    May 18, 2014
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    59
    I hear ya. The unfortunate part is my gut has been telling me all along. Really wanted to enjoy a few summers with my boys cruising around town and hitting some local fire trails for picnic lunches.
    I will look at it closer this weekend do see what a set of pushrods will set me back and what the install will entail.
    if I could squeeze a few summers out of it and then rebuild it, I would be good with that.
    but hey, I got a smoking deal!
     
  5. Jun 6, 2014
    tarry99

    tarry99 Member

    Northern California
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    I hear what your saying ...............but all engine internals have relationships with other internal parts.........putting a band-aid on it by replacing one thing does not necessarily fix the problem. The push rods bent not on there own accord...........All components are all interconnected and must work in Concert together.
    You may have been better off just changing the oil and driving it while hoping for the best!....................Been at this stuff for a long time , no smoke and mirrors here!
     
  6. Jun 6, 2014
    Southtowns27

    Southtowns27 Custom Title

    The Backhills of...
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    Yep, bent pushrods are not the problem. They are a symptom of a much bigger problem. If you are finding pieces of timing gear in the pan, there's a pretty good chance it failed in the past. When it failed, the pistons may have hit the open valves, bending the pushrods. Someone may have just replaced the gear failing to check the pushrods or for any other damage. If my theory is correct, I wouldn't be surprised to find a bunch of bent valves too.
    Time for a total rebuild. I know that's what you want to hear, but at this point you're trying to put a band-aid on a hear attack. If a rebuild is out of the budget, track down another known good running engine for a few hundred bucks, bolt it in and go.
     
  7. Jun 6, 2014
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Busted timing gear...? Southtown27 may be on the right track. Used engines are cheap enough.
     
  8. Jun 6, 2014
    Heatseeker

    Heatseeker Member

    Calaveras...
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    Water filled cylinders have been know to bend and break things as well.
     
  9. Jun 6, 2014
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Pistons and connecting rods, more than pushrods, I'd think, since the valves have to be closed for the hydro-lock to occur.
     
  10. Jun 6, 2014
    Heatseeker

    Heatseeker Member

    Calaveras...
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    You are probably right PeteL. I was just reminiscing back to when I blew a bbc to smithereens in my boat when I wrote that. On tear down, I found broken/bent rods and damaged valve train components. The valve train carnage was probably collateral damage. But it all started with a water filled cylinder.

    I hate water filled cylinders...
     
  11. Jun 7, 2014
    djbutler

    djbutler Sponsor

    Rio Linda CA
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    Well Buddha44,
    I don't have any thing to tell you that the others haven't already. A motor with as many issues as you have seen may not be something you can bandaid up and drive with any confidence.

    On the other hand, I have a 225 that had 2 bent pushrods. Mine may be a little different though. I got it after 20 years of storage and neglect, and everthing in this Jeep had to be dissasembled, cleaned and lubed. The engine did fire up briefly when I inspected it before buying the Jeep, but it had some valve train noise. No bottom end noise though, and it made oil pressure so I bought it.

    During my work on it to get it running, I pulled the engine and put it on a stand, pulled the pan and valve covers to clean out the sludge. That's when I noticed the 2 bent pushrods, both on intake valves. I pulled them out and straightened them out using a bench vise, saw no cracks and re-installed them. These are solid pushrods, not hollow like SBC. My theory is that 2 of the intake valves were stuck with varnish and when the PO attempted to start the engine the pushrods bent. After a few moments or running maybe the valves freed up and started to open and close, so no further stress was on the pushrods. Once I straighted them back, the valve train noise was gone.

    I have several thousand miles on this engine after that with no issues other than a mild rear main seal leak. Maybe I'm luckier than some, or maybe it is the rebuilt 231 on the stand ready to replace it that keeps the old one running.

    Don
     
  12. Jun 7, 2014
    oddfirejeeper

    oddfirejeeper Active Member

    Hamilton, MI
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    i may be wrong but isn't a 225 a non interference engine when the timing goes?
     
    Last edited by a moderator: Jun 7, 2014
  13. Jun 7, 2014
    oddfirejeeper

    oddfirejeeper Active Member

    Hamilton, MI
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    " or maybe it is the rebuilt 231 on the stand ready to replace it that keeps the old one running."

    that's funny how that works
     
  14. Jun 7, 2014
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    I had a couple bent pushrods. And a couple rounded off lobes on mine. Didnt notice any damage to pistons or valves. I say replace the pushrods and do a compression test on it. Bend the rods straight and then do the compression test. Cant hurt anything at cranking speed. At least this way you can see if the cylinders are sealing up before spending any money on it. Pay attention to the pressures on the cyls with the bent rods compared to the others. You dont even have to put the intake back on yet for compression test.

    Drive it and work on finding another engine to work on while your driving this one..
     
  15. Jun 7, 2014
    Walt Couch

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

    cordele, Ga.
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    Same as djbutler on 2 bent push-rods. Engine had not been rotated in many years and two valves had stuck open. In the process of unlocking the engine I bent the push-rods. Straightened them out, checked with a straight edge and re-installed. Worked good. Solid push-rods are tough and will last forever if service is proper.
     
  16. Jun 7, 2014
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    You are correct
     
  17. Jun 7, 2014
    tarry99

    tarry99 Member

    Northern California
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    Neglect & Dirty Gummed oil and crank case.........................Hydraulic lifters is where I would be looking.
     
  18. Jun 7, 2014
    Buddha44

    Buddha44 Member

    San Clemente, CA
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    All you guys made some great points!
    i think for sure I want to check lifters and see if they are wearing correctly. If they are...think I will hammer pushrods straight, slap it back together and hold on for a major rebuild, maybe next summer.
    if the lifters are a mess, dimpled in, etc., I'm gonna close the garage door, grab my surfboard, jump in my 66 Chevy pickup and head for the beach.
    in previous posts I talked about how RICH this jeep runs. Checked all the basics. Wonder if that could be related to messed up valve train?
    BTW, I thought the 225 came with a 1 barrel? Mine has a 2. Like I said, new to the jeep world.
    i will keep you posted, prob gonna pull lifters today...
     
  19. Jun 7, 2014
    Walt Couch

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

    cordele, Ga.
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    Another thing I had to do from partially stuck open valves was spray PB Blaster around valve stems and beat on the top of the valve (with spring) with a rubber hammer until the valves closed completely and assemble the rockers and run a compression check.
     
  20. Sep 8, 2014
    John A. Shows

    John A. Shows Comic Relief

    Mendenhall...
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    Hey Nick...I'm reviving this old post...maybe even hijacking...but last year I took my jeep across my pond. When I got to the other side the bank was just too steep for me to pull on out. Didn't stop me from trying though and I over revved my engine (tremendously according to the bystanders who were listening). Anyway after getting pulled out, I limped on in to the shop with it back firing like crazy. It has sat in the shop for almost a year now and I finally pulled the valve cover. Three of my push rods were not under their rocker arm. 2 were straight but one was bent. My brother took a straight rod and held it on top of the three lifter while I turned the engine over and he says that all three of them have their full range of motion so there's nothing wrong with my lifters. He says I just need to replace the one bent rod and he says that all that happened was that I over revved the engine.

    Do you have any input on this?

     
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