GNAT - Rebuild - The Sequel

Discussion in 'Car Builds, Projects, Idea's Experiments' started by Nathan, May 11, 2015.

  1. ScottinBend

    ScottinBend Space Cowboy
    Supporting Member

    May 4, 2009
    8,767
    2,547
    113
    Bend, OR USA
    Ratings:
    +2,678 / 1 / -0
    Chad said he could do it........
     
  2. Crashton

    Crashton Club Coordinator

    Jun 4, 2009
    19,445
    10,057
    113
    Retired old fart
    Hooterville Ohio USA
    Ratings:
    +11,698 / 2 / -0
    YES!
     
  3. Nathan

    Nathan Founder

    Mar 30, 2009
    25,144
    10,052
    113
    Writer
    Short North
    Ratings:
    +10,069 / 0 / -0
    Not to put words in Chad's mouth, but I think he means there is time. Not that they can do it there at the shop.
     
  4. Spa2k

    Spa2k Well-Known Member

    May 9, 2013
    1,955
    975
    113
    Iowa
    Ratings:
    +975 / 0 / -0
    You guys are making my head hurt. I miss the days when I could whack a carburetor with a hammer to get the engine running again. :sad:
     
  5. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
    Lifetime Supporter

    May 4, 2009
    3,532
    2,896
    113
    Professional Facilitator and Alignment Consultant
    Holly Springs, NC
    Ratings:
    +2,896 / 0 / -0
    I would get the injectors cleaned and flow tested, while it's apart
     
  6. Norm03s

    Norm03s New Member

    May 5, 2009
    4,936
    534
    0
    Working at being retired.
    Somewhere in Sykesville. Md.
    Ratings:
    +534 / 0 / -0
    Chad probably knows where to get the injectors done right or ask the head designer.
     
  7. Norm03s

    Norm03s New Member

    May 5, 2009
    4,936
    534
    0
    Working at being retired.
    Somewhere in Sykesville. Md.
    Ratings:
    +534 / 0 / -0
    YES, absolutely. You don't want to revisit this issue again. They will be able to tell you the results too.
     
  8. CarlB

    CarlB Active Member

    May 4, 2009
    252
    54
    28
    Ratings:
    +54 / 0 / -0
    It is difficult to diagnose a problem like this without seeing it first hand, but the valve got hot enough to burn, and the remaining valves didn't. We know it was the hottest. A lot of times there isn't one answer. Several things together probably caused the problem. Eric pointed at the very likely ones. I would flow test the injectors to make sure that isn't the problem. I suspect what you will find is that one is flowing a lot less than the others, but the O2 sensor problem probably contributed as well. Not likely but to show how these problems can be hard to identify. The engine was detonating and eating the aluminum away between the valve and the spark plug. Was there a coolant issue that caused the problem? Was there a hot spot that caused detonation and ultimately burned the valve.
     
  9. Detroit Tuned

    Detroit Tuned Well-Known Member
    Motoring Alliance Founding Sponsor

    May 5, 2009
    301
    319
    63
    evertyhing
    Metro Detroit
    Ratings:
    +319 / 0 / -0
    Cooling System looked totally solid and had no problem.
     
  10. Detroit Tuned

    Detroit Tuned Well-Known Member
    Motoring Alliance Founding Sponsor

    May 5, 2009
    301
    319
    63
    evertyhing
    Metro Detroit
    Ratings:
    +319 / 0 / -0
    #70 Detroit Tuned, May 28, 2015
    Last edited: May 28, 2015
    High(er) res:

    [​IMG]
     
  11. Dave.0

    Dave.0 Helix & RMW Powered
    Lifetime Supporter

    May 4, 2009
    25,021
    13,497
    113
    Burbs of Philly, PA
    Ratings:
    +14,644 / 10 / -4
    Send the injectors and the head to Jan. He has a guy that with cleaned and flow tested. I just had my old 450's done with new O rings and also got new pigtails.

    Fyi~ mine are for sale for $ 290.00 of anyone needs them.
     
  12. MCS02

    MCS02 Moderator
    Staff Member Articles Moderator Supporting Member

    Jul 31, 2009
    11,305
    6,277
    113
    Male
    Ratings:
    +8,070 / 10 / -3
    A little JB wield and its as good as new!:D
     
  13. ColinGreene

    ColinGreene Well-Known Member
    Motoring Alliance Sponsor

    May 15, 2009
    438
    293
    63
    Male
    Orange county Ca
    Ratings:
    +293 / 0 / -0
    it looks like a typical burned valve to me.
     
  14. CarlB

    CarlB Active Member

    May 4, 2009
    252
    54
    28
    Ratings:
    +54 / 0 / -0
    Chad, I did not mean to imply a problem with the cooling system. I did not word that well. I agree with Colin, and think the likely cause was the O2 signal and probably partly the injectors. When you look at the pictures, especially the latest one you can see the detonation (small shiny pot marked area between the valve and the spark plug). I was trying to point out that these problems are often the result of several things and that their diagnosis is complicated. The detonation is the classic chicken or the egg. What came first the detonation or the burning valve. Potentially but not likely the problem was a blocked cooling passage in the area of the detonation. You couldn't figure that out without sawing the head open, and it isn't worth doing. The intent of bring this up is to point out that a lot of the time these things are caused by multiple problems, and you want to check what you can to eliminate as much as possible. Flow the injectors.
     
  15. Nathan

    Nathan Founder

    Mar 30, 2009
    25,144
    10,052
    113
    Writer
    Short North
    Ratings:
    +10,069 / 0 / -0
    Welp, spoke to Jan today and Dave.0 hit the head on the nail...

    Jan requested that the head, injectors and pig tails be sent to him to be checked over. We'll see if the head can be repaired properly.
     
  16. Dave.0

    Dave.0 Helix & RMW Powered
    Lifetime Supporter

    May 4, 2009
    25,021
    13,497
    113
    Burbs of Philly, PA
    Ratings:
    +14,644 / 10 / -4
    Yeah the valves and all the valve seats should be refreshed / refreshed. After the injectors are cleaned and rebuilt with new O rings and pigtails you should be good to go again.

    Also don't forget to have the single prong NGK's installed and get the ViPEC tune updated.
     
  17. TheModFather

    TheModFather Well-Known Member

    May 15, 2012
    6,023
    5,310
    113
    11 years in the ARMY, 2 years of being a multitale
    North Denver CO.
    Ratings:
    +5,322 / 0 / -0
    Yes to all of the above. :)
     
  18. mrntd

    mrntd Well-Known Member
    Supporting Member

    Sep 30, 2011
    5,083
    1,762
    113
    Male
    Sales and Marketing manager
    Hilliard, Ohio
    Ratings:
    +1,763 / 0 / -0
    I'm just enjoying the discussion. :popcorn::beer
     
  19. Crashton

    Crashton Club Coordinator

    Jun 4, 2009
    19,445
    10,057
    113
    Retired old fart
    Hooterville Ohio USA
    Ratings:
    +11,698 / 2 / -0
    :popcorn:
     
  20. Nathan

    Nathan Founder

    Mar 30, 2009
    25,144
    10,052
    113
    Writer
    Short North
    Ratings:
    +10,069 / 0 / -0
    Some of you must be bloated with all the popcorn you've been munching on since the last update.

    Jan has the Head and Injectors.

    The head is repairable. Needs new seats, these will be slightly bigger than the current ones, meaning bigger valves too.

    The ports will be reprofiled too. A lot about shaping has been learned since my head was done back in 2007.

    Probably replace the OEM cam too.

    Injectors are headed to the injector dude.

    So that is where we stand right now.

    Tee-shirt design is in the works. There is also a watercolor print that will be available too.

    More Soon...
     

Share This Page