Results 1 to 18 of 18

Thread: Cold #2 cylinder after overhaul on C90-12F

  1. #1
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like

    Cold #2 cylinder after overhaul on C90-12F

    Posting about a friend’s Continental C90-12F that has a cold #2 cylinder.
    Engine recently overhauled, however on the engine runs the number 2 cylinder never gets warm.

    Items that have been checked and rechecked;
    · Mag timing, both internal and to the engine
    · All of the ignition leads to the right cylinders
    · Compression checked
    · Spark plugs check to make sure they make spark and at the right time. Put all of the plugs on the leads and rotated the engine starting with the #1 cyl to verify that all plugs fired in the correct sequence (firing order 1-3-2-4) for the l/h rotating mags.
    · Jug was pulled and inspected along with the lifters
    · Intake runner and exhaust checked for blockage

    I suggested that he check the internal timing via a procedure in a Lycoming guide, even though the other 3 cylinders seem to be playing well. Even though written for a Lycoming, should still work on a Continental. (see page 94 in this link http://www.joespiper.com/Lycoming.pdf)

    Puzzled since all of the component to make fire are there and at the right sequence, but still no luck.

    Has anyone else seen symptoms similar to this?

  2. #2
    nanook's Avatar
    Join Date
    Aug 2002
    Location
    northern alaska
    Posts
    1,639
    Post Thanks / Like
    Turn the engine over with the rocker cover off and see if the valves are opening and closing.

    Any blockage in the intake or exhaust?

  3. #3

    Join Date
    Jan 2007
    Posts
    1,602
    Post Thanks / Like
    I would vote for valve issue also. Was the cam checked at overhaul?
    DENNY

  4. #4
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Quote Originally Posted by nanook View Post
    Turn the engine over with the rocker cover off and see if the valves are opening and closing.

    Any blockage in the intake or exhaust?
    Did both of these task already and they check good.

  5. #5
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Quote Originally Posted by DENNY View Post
    I would vote for valve issue also. Was the cam checked at overhaul?
    DENNY
    To the best of my knowledge the case and all of the internal components were sent to Tulsa during overhaul. I think John said the case went to Divco and the other internal items went to Rick Romans. Not sure who did the cylinder inspections. The #2 cylinder was pulled yesterday along with the lifter components and taken to Midwest here at the KEWK with no issues noted.
    Last edited by Curtis; 10-22-2015 at 03:45 AM.

  6. #6
    Chuck Avon's Avatar
    Join Date
    Apr 2011
    Location
    Hohenwald Tn
    Posts
    366
    Post Thanks / Like
    Did you check push rod lengths.

  7. #7
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,070
    Post Thanks / Like
    Cold? As in really rough running? Did you do the wet finger test on the exhaust pipe? OR do you have a four cyl CHT instrument and the #4 probe doesn't work?
    N1PA

  8. #8
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    18,426
    Post Thanks / Like
    I use an infer red head gun to compare temps. I suspected a stuck valve. Mag check is ok? Even if one lead or plug was bad it should fire on the other. Could have a lead or plug breaking down. Swap plugs to another cylinder. Was a lead checker used on the leads?
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  9. #9

    Join Date
    Jul 2010
    Location
    Elizabeth, WV
    Posts
    499
    Post Thanks / Like
    I know you checked it but my vote is mixed up leads, probably between #2 and #3. Or was it 2 and 4? Ran well enough and smooth enough I couldn't believe two cylinders were screwed up. jrh
    You can't get there from here. You have to go over yonder and start from there.

  10. #10
    aktango58's Avatar
    Join Date
    Aug 2004
    Location
    18AA
    Posts
    9,045
    Post Thanks / Like
    plugs act different when under pressure. change the plugs around like suggested.
    I don't know where you've been me lad, but I see you won first Prize!

  11. #11
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Quote Originally Posted by Chuck Avon View Post
    Did you check push rod lengths.
    I will ask but I haven't heard him say they have checked that.

  12. #12
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Quote Originally Posted by skywagon8a View Post
    Cold? As in really rough running? Did you do the wet finger test on the exhaust pipe? OR do you have a four cyl CHT instrument and the #4 probe doesn't work?
    No EGT or CHT. Cold as in the other three cylinders are HOT after the engine run and the #2 cylinder is still ambient temp.

  13. #13
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Quote Originally Posted by Steve Pierce View Post
    I use an infer red head gun to compare temps. I suspected a stuck valve. Mag check is ok? Even if one lead or plug was bad it should fire on the other. Could have a lead or plug breaking down. Swap plugs to another cylinder. Was a lead checker used on the leads?
    #2 is ambient temp after engine run. I just suggested to him to swap the plugs with another cylinder. Have not checked leads with tester yet.

  14. #14
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Sorry for the multiple replies, just noticed the "Multiple Quote this Message" button.

  15. #15
    Curtis's Avatar
    Join Date
    Nov 2014
    Location
    KEWK
    Posts
    38
    Post Thanks / Like
    Just got a call from John on this issue. Had the engine guy from Midwest Aircraft in Newton come over and check out the engine run. After the initial engine run and verifying the cold #2 cylinder he suggested a second engine run, but this time take the RPM over 1,300 to get carb out of the idle circuit. Cylinder #2 started working. With the newly overhauled engine John never wanted to increase the RPM with it running rough so we had never ran it much above idle. Never would of believed that a bad idle mixture setting would cause just one dead cylinder. I do appreciate all of the feedback on this issue and hopefully someone else can learn from our trials.

    If anyone has any additional question on this please do not hesitate to contact me and I will see if I can get the answer.

  16. #16
    aktango58's Avatar
    Join Date
    Aug 2004
    Location
    18AA
    Posts
    9,045
    Post Thanks / Like
    Love it when it is simple!

    more power is always the answer
    I don't know where you've been me lad, but I see you won first Prize!

  17. #17

    Join Date
    Jan 2007
    Posts
    1,602
    Post Thanks / Like
    aktango58 had a great suggestion!! The plug issue seems not to be the problem with this engine but I had one that did great at 1800 RPM but dropped out at 2100. Kind of felt slow at take off and ran ok in cruise but I did a mag check at 2400 and scared myself!!! The good thing about what is the problem posts is guys bring up stuff you might not be aware of or forgot to check. Now if I can only keep this stuff from leaking out when I lay down to sleep.
    DENNY

  18. #18
    aktango58's Avatar
    Join Date
    Aug 2004
    Location
    18AA
    Posts
    9,045
    Post Thanks / Like
    Quote Originally Posted by DENNY View Post
    Now if I can only keep this stuff from leaking out when I lay down to sleep.
    DENNY
    Ear plugs.
    I don't know where you've been me lad, but I see you won first Prize!

Similar Threads

  1. Replies: 3
    Last Post: 02-12-2011, 11:24 AM
  2. Scott Master Cylinder overhaul
    By Billy-250 in forum Tips and Tricks
    Replies: 17
    Last Post: 07-11-2009, 06:19 PM
  3. Cold Cylinder?
    By CptKelly in forum Cafe Supercub
    Replies: 8
    Last Post: 05-13-2005, 12:47 PM

Bookmarks

Bookmarks

Posting Permissions

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