Fuel injector assembly 86 TR | FerrariChat

Fuel injector assembly 86 TR

Discussion in 'Boxers/TR/M' started by Nick G48, Jun 7, 2021.

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  1. Nick G48

    Nick G48 Karting

    Aug 18, 2016
    57
    Clinton Township, Michigan 48316
    Full Name:
    Nick
    Have a question about fuel injector assembly. When assembling, o ring tears. Tried dry and also tried a little sil glide. See video for explanation.
    Thanks for any info
     

    Attached Files:

  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,041
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    I don't recall having a lot of grief with that, but it was some years ago I last did it. Are you sure that you have the right cross-section o-ring? What is the ID of the o-ring when installed, and the OD of the injector nose? The "interference" should be fairly small.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,041
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    I dug back thru my notes, and have that 101030 o-ring (purchased from McCann) as:

    ID (free state) = 9mm (or maybe a tad less)
    Cross-section (free state) = 1.7~1.75mm
     
  4. Nick G48

    Nick G48 Karting

    Aug 18, 2016
    57
    Clinton Township, Michigan 48316
    Full Name:
    Nick
    mine measure 9mm (ID), 12.5mm (OD). Cross section is 1.72mm
    Now I do not understand what the problem is. Mine measure the same as yours. If you look at my video, you can see that my o rings do not fit
    Is it possible that there are differences in early TRs?
     
  5. Nick G48

    Nick G48 Karting

    Aug 18, 2016
    57
    Clinton Township, Michigan 48316
    Full Name:
    Nick
    I also just measured the old O-Ring and it measures 9mm ID, 11.25 OD. Cross section measures 1.12.mm. This o-ring looks worn. My measurements may be off a little but I am close.
     
  6. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,041
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    It's normal for the old o-ring to be smushed (and set) into a more rectangular shape matching the groove. Haven't heard of any changes to the groove geometry. Only other thing that I can think of is a material difference where the stock o-ring is a softer material (so more easily deformed) and now the later o-ring is a harder material. You could try something like making a tapered pin about the same OD as the injector nose and inserting it to (gently) force the o-ring into the deflected shape, let it sit overnight, remove the tapered pin and see if you can then more easily insert the injector (with lube) without tearing it -- just a thought...
     
  7. Nick G48

    Nick G48 Karting

    Aug 18, 2016
    57
    Clinton Township, Michigan 48316
    Full Name:
    Nick
    Thanks, I will give that a try.
     
  8. carguy

    carguy F1 Rookie

    Oct 30, 2002
    3,402
    Alabama (was Mich.)
    Full Name:
    Jeff
    The last time I installed new o-rings (I think they were green in color) it took a good bit of force to get the o-ring started / rolled onto the end of the injector, seems like I used petroleum jelly for lubricant....after that your good to go.
     
    turbo-joe and vincenzo like this.
  9. vincenzo

    vincenzo F1 Rookie

    Nov 2, 2003
    3,373
  10. Nick G48

    Nick G48 Karting

    Aug 18, 2016
    57
    Clinton Township, Michigan 48316
    Full Name:
    Nick
    I finally have a pretty good system to fit the O rings. I did check the size of O Ring and it checks good.
    I seated the O ring and then turned down an old injector by about .010 and put that through the O ring overnight. We used NAPA Sil-Glyde as a lubricant. After seating overnight we removed the injector and put in a new injector. Pushed slowly and it gradually went in place. I think we are good. Thanks for all the advice.
     
    Veedub00 likes this.
  11. Veedub00

    Veedub00 F1 Rookie
    Owner Silver Subscribed

    Jun 30, 2006
    4,887
    Troy, Michigan
    Full Name:
    James

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