Results 1 to 10 of 10
  1. #1

    Default Bent Push Rod '86 260 Mercruiser 350

    I would really appreciate some advice....I had a small clanking sound in my port engine. Over 30-45 minutes of running it got worse. There was no backfiring or other problems. Power remained "normal" as far as I could tell. Compression was checked and Cylinder 5 had "slightly low" compression and a noise was noticed in Cylinder 2. It was decided to remove the heads and see what was going on. (No leak test, no checking under the valve covers first.?) Manifolds were removed, valve covers were removed. Rocker Arms were almost all removed when a bent push rod was found at cylinder 2. So, what to do then?? Given the possible new issues with removing the heads, cracking them, creating new issues, etc. I am leaning towards A) putting a new push rod in, putting the manifolds back on and turning the engine over to see if any other problems can be seen vs B) going ahead and taking the heads off to be rebuilt. If "A", then if no other problems can be found, the issue is resolved and the cost is ~$150 vs "B" at $1000- $1200. If other problems are found then, tear it back down and proceed to remove the heads (costing ~$300 more than it would have otherwise because of putting it back together and then taking it apart AGAIN). Thoughts..."A" or "B" or.... Thank you so much!

  2. #2

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    Welcome aboard ! I would get a different mechanic.

  3. #3
    Join Date
    Sep 2010
    Jersey Shore

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    I agree with Master mechanic.

    I would also do option "A"

    If you find that the engine still has a noise, I would not even attempt to repair a 26 year old engine unless it was FWC. In the long run a replacement long block will serve you better and save you money.
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  4. #4
    Join Date
    Aug 2008
    Jamesport, New York, United States

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    The two posts above this one are sound advice. In todays world, finding a mechanic who can accurately diagnose a problem is getting harder to find. Push Rods do fail on there own although an underlying cause is always possible. Check the Valve action on that particular valve and see if it feels "Sticky". Compare it to others. You may have had water in that cylinder at one time and this caused rust to form that has finally caused it to stick or Jam. Seeing as the Intake manifold is off you should be able to do a visual inspection, looking for rust on that Valve Stem. No harm in spraying WD40 into all the ports if you intend to just replace the Push Rod and go for it. All too often an engine is not Fogged Out upon lay up for the winter or whatever. Always, always always add Marvel Mystery Oil to your gas. I use 1 Oz. to every 3 gallons. This lubricates the Valves, preventing Bent Push Rods. Please come back and let us know how you did. Al W.

  5. #5

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    Regular oil will do that also. I never add anything but then again that's me. Option " A ".

    Where are you in the real world generally... maybe we can recommended someone who won"t screw you and do a good job for you.

    I am getting tired of asking people where generally they keep the boat. Please to all that read this put up a general area where you have the boat.

  6. #6

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    Thank you gentlemen! I really appreciate your time and kind advice Master Mechanic, DocksideMarineServices and Wickeral. *I am in Nashville, TN. *I did get a new mechanic; but, I am not sure he is much better. *I asked him about doing a leak down test and he said he did not have a gauge and anyway it was a waste of time because it didn't tell you anymore than a compression test. *I did not explain it to him. *Anyway, I did try to pick "A". *He got a new push rod and a new rocker arm. *He put them in and then tried to tighten the rocker arm down. *He told me when he did that the rocker arm would not stay on top of the valve because the top of the valve stem was rounded over from the rocker arm not riding on it squarely after the push rod was bent. *So, he took both heads off to take to the machine shop. *I asked him about checking valve movement and he said he could; but, it wouldn't matter since the rocker arm wouldn't stay on top anyway. *I was not there when he tried to install the new rocker arm; but, I was there when he took the old one off and it is true the valve stem was rounded over on one side. *Still, I am not sure why the rocker arm would not "stay on top". *In any case, now we will see what the machine shop says. *The mechanic has already told me if my head's are cracked, he has some at home he will sell me. *Sheesh. *

    Of nearly equal concern to me at this point is that starboard engine. *I believe both engines have always been treated the same (i.e. not fogging, etc). *So, I am wondering what I can do to the other engine to prevent or delay this happening in that one also. *I will add the Marvel Mystery Oil. *

    Thanks again.

  7. #7

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    If you know what to look for when you read your plugs they will tell you almost everything about the engines health.


    Do a compression test... write down the numbers and keep track of what plug came out of what hole, warm engine, all the plugs out and throttle fully down. Now you will have a base to compare against the next time you change out your plugs.

  8. #8
    Join Date
    Aug 2008
    Jamesport, New York, United States

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    Chevy small blocks are a very forgiving engine. Seeing as your compression was reasonable for an older boat I would have considered replacing the valve that had deformed. We old timers know how to lap a valve and save lots of dollars. Today it's easy to throw too much money at our boat engines. Good luck, Al W.

  9. #9

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    Thank you for that advice. Tonight my mechanic told me that both heads were cracked and could not be repaired. He said he has a pair at his house he will sell me for $500 each including rocker arms. Sheesh...Once you are this far in...I thought about going to see them at the machine shop. But, that probably won't do mush good. I guess now the question is to spend that much on an old engine or get another one....?? Frustrating.

  10. #10
    Join Date
    Jul 2008
    Northboro, Ma, USA

    Default Re: Bent Push Rod '86 260 Mercruiser 350

    I just had a set of warped and cracked heads repaired, $400.00

    Not sure how bad yours are but that price is not that bad for a ready to go set of heads, Maybe see if you can get them for less considering you will be paying labor also. and gaskets sets.......

    A complete remanufactured LONG block is ~ $1700 and up depending on where and who you get it from... not including labor.

Similar Threads

  1. Push rod problem!
    By english_man_in_norway in forum Mercruiser Sterndrive Forum
    Replies: 9
    Last Post: 09-22-2011, 03:40 PM
  2. Mercruiser 4.3 valve push rods.
    By english_man_in_norway in forum Mercruiser Sterndrive Forum
    Replies: 5
    Last Post: 11-10-2010, 07:28 PM
  3. Push rod
    By tandlb in forum Crusader Marine Engine Forum
    Replies: 7
    Last Post: 03-07-2010, 09:31 AM
  4. 351 W bent push rod
    By Crabbie in forum Mercruiser Sterndrive Archive
    Replies: 12
    Last Post: 04-26-2007, 07:46 PM
  5. 37 with 6 bent push rods
    By tattooed in forum Mercruiser Sterndrive Archive
    Replies: 6
    Last Post: 05-28-2006, 06:19 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts