Page 1 of 2 12 LastLast
Results 1 to 10 of 14

Thread: Severity of Broken Valve Damage

  1. #1
    N404CX's Avatar
    Join Date
    Aug 2011
    Location
    Los Angeles
    Posts
    43

    Severity of Broken Valve Damage

    I was inspired to post this message by Brady Lane's latest article where he asks veterans for help.

    My brand new 2180 with less than 30 minutes on it had an intake valve break. It ruined the head, the intake manifold, and chewed up the top of the piston pretty well.

    pistons.jpg

    Can I replace the broken/damaged parts and trust there is no internal damage, or should I insist the builder open up the case.

    Thanks.

  2. #2
    Neil's Avatar
    Join Date
    Aug 2011
    Location
    Monroe, LA
    Posts
    87
    The safe answer is to say tear it down and see if there is any damage to the rod such as being bent since it appears that the piston was impacted right over the wrist pin boss on one side. You may be able to remove the rod from the crank shaft by removing the opposite cylinder and uppon evaluating what you see, have a talk with the builder and get his opinion.

    Usually when a valve breaks so early in the life of an engine it is a faulty valve. Many valves are made in two pieces, those being the stem and the head. I flew most of the hours in my log book behind a VW conversion without a valve failure and I used the one piece stainless valves from Manley Valve Company. That is not to say I never had any issues. I had problems with valve guides due to a flawed head casting. Also there were valve spring issues that were solved by converting to Chevrolet valve springs but that is another story.

    I am curious, did the valve simply break, or did it stick in the guide and was then broken when the piston hit the valve?
    Last edited by Neil; 05-13-2012 at 08:09 PM.

  3. #3
    N404CX's Avatar
    Join Date
    Aug 2011
    Location
    Los Angeles
    Posts
    43
    Quote Originally Posted by Neil View Post

    I am curious, did the valve simply break, or did it stick in the guide and was then broken when the piston hit the valve?
    It did not stick in the guide. It is broken right below the keeper, and again mid-shaft. The part with the head is pounded into the cylinder head, and the piece of the shaft is jammed into the intake chamber.

    sm_P1010033.jpg

  4. #4
    Neil's Avatar
    Join Date
    Aug 2011
    Location
    Monroe, LA
    Posts
    87
    Among the things I think you should consider is to replace all the intake valves as the odds are they are all from the same lot.

  5. #5
    steveinindy's Avatar
    Join Date
    Jul 2011
    Location
    Indiana
    Posts
    1,449
    Quote Originally Posted by Neil View Post
    Among the things I think you should consider is to replace all the intake valves as the odds are they are all from the same lot.
    That would be my suggestion but then again I'm not an "engine guy". I'm just glad to hear that you're OK and are able to be around to worry about this.

    All the best,

    Steve
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  6. #6

    Join Date
    Oct 2011
    Location
    New Hampshire
    Posts
    1,037
    Question,

    If broken bits went into the intake manifold, did some get sucked into other cylinders? That happens with other engines that have failures of the type described. Other cylinders can suffer FOD damage.

    Does an examination of the oil screen or cutting open the oil filter show any debris from the failure? You will likely need to flush the entire engine to get any debris cleaned out.

    Best of luck,

    Wes
    N78PS

  7. #7
    N404CX's Avatar
    Join Date
    Aug 2011
    Location
    Los Angeles
    Posts
    43
    Thanks, Wes, I think anything in the adjacent cyl. can be cleaned out.

  8. #8

    Join Date
    Jul 2011
    Location
    Justin, Texas
    Posts
    73
    Looking at the pictures, were it my engine, there would be no question about opening up the case. You had enough force on the piston to drive that valve into the head. Without pulling it apart, you have no way of knowing if there was damage to the rod and the crank. I would be looking particularly at the rod, crank and the case around the cylinder studs. I hope that you don't find any damage, but it would be much better to find it now than on takeoff.

  9. #9

    Join Date
    Jul 2011
    Posts
    1,556
    What is a "2180" , never heard of one?

  10. #10
    N404CX's Avatar
    Join Date
    Aug 2011
    Location
    Los Angeles
    Posts
    43
    VW engine of 2180 cc. displacement, horiz. opposed 4-cyl. 92mm bore, 82mm stroke.

Posting Permissions

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