Headgasket replaced and failed shortly after? Do anything different next time?

Discussion in 'Gen 3 Prius Main Forum' started by AmazingFacts, Nov 5, 2021.

  1. burrito

    burrito Member

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    Not enough data points to come to a conclusion; just get more data! You're already in the store: Try another shelf, another partition, or another ruler/level. If you're at Home Depot, just don't try anything in the lumber section.
     
  2. AmazingFacts

    AmazingFacts Junior Member

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    Allright update time. Got the head back from the shop and he shaved off in some parts 7000th to make it straight. He said it was slightly warped. By the way, make sure you go to a good machine shop who's willing to take time in explaining what they're going to do and why. I called about 7 machine shops and finally found one that's excellent. Jay's Machine Shop in Santa Clara...highly recommend him. He's a one man shop and has been doing this for 50+ years.
     
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  3. rjparker

    rjparker Senior Member

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    Seven thousands of an inch out. Good thing you took it to a machine shop. Many don't. It was three times the max tolerance. So much for the straight edge and feeler gauge theory.
     
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  4. burrito

    burrito Member

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    Not if you take your straight edge to the machine shop first!
     
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  5. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yeah the amount he removed was 3.5 times the spec'd max warpage:

    upload_2021-11-12_7-5-27.png


    upload_2021-11-12_7-12-34.png

    Conversion of how much he removed, to millimeters:

    upload_2021-11-12_7-15-0.png

    Only thing, WAS that the variation, or just the minimum amount he could practically plane off?
     
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  6. tony_2018

    tony_2018 Member

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    oil analysis, will tell you more about engine.
    from there you'll know if the engine can live on after a headgasket replacement.
     
  7. AmazingFacts

    AmazingFacts Junior Member

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    Ok all done with the head gasket replacement. Boy it was more work than anticipated, but thanks to God it's done and it's running great without any CELs!

    One tip when torquing/tightening the head bolts and the cam rack bolts is to have the torque tightening sequence nearby and count out loud as to which bolt you're on. You don't want to lose track and have to start over, or worse yet, don't want to turn the bolt twice and break it.

    Regarding the heading being machined down more than specs, it would be a good thing to let the machine shop know.

    More updates as I rack up mileage.

    If anyone needs any help in the SF bayarea, let me know. I'm happy help out.
     
  8. ASRDogman

    ASRDogman Senior Member

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    Glad all is working for you!
    The thing about the head, if it's machined too far, the valve and piston can meet. Which is never good.
    They are already pretty close.
    Some manufactures have thicker head gaskets just for that, and to keep the compression ratio correct.
    I am not sure if they still have those or do that anymore.

    You can use a yellow crayon to mark each bolt with a line, then another line to make a "plus" on it.
    If a third time, another line. We used that when adjust valves, you mark the one you just did.
    Then you know you haven't missed any. I always marked the last one! Even though I knew there
    weren't anymore to do.

    I'm sure you'll happy for all the hard work you did and the satisfaction of a job well done!

     
    #28 ASRDogman, Nov 15, 2021
    Last edited: Nov 15, 2021
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  9. AmazingFacts

    AmazingFacts Junior Member

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    Thanks for the encouraging words ASRDogman and yes I agree regarding the valves and pistons meeting.
    And great idea regarding the crayon. I'll have to use that next time!
     
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  10. douglasjre

    douglasjre Active Member

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    Did one head gasket and 70k miles later still works. Did another w a Fleabay HG and it lasted 10k be crapping out. Stay far far away from Fleabay. Lots o Chinese junk and scammers.

    It's hard to imagine your motor not burning oil. I had one that did initially and after 30k of WOT it stopped burning oil. Not sure why.

    I guess u can do a HG but I won't do it again. Not worth the risk of it coming back...
     
  11. The Critic

    The Critic Resident Critic

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    Yeah, that seems like a lot. I would be concerned about timing issues since the marks definitely will not line up 100% if the head had that much material removed.

    OP, glad to hear that the repair was successful. I wish I saw this thread sooner or else I would have offered to help. I am about 40 miles north of you.

    I was working on this 2gr-fe while you were doing yours. The Prius is easy in comparison. 65673543856__445C8D4E-7CBC-40F6-9C3F-9435F6F86595.jpg
     
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  12. AmazingFacts

    AmazingFacts Junior Member

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    Thanks for your offer to help TheCritic. How nice of you.
    Wow you had to pull the entire engine out to change the heads on the 2gr-fe?
     
  13. The Critic

    The Critic Resident Critic

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    Yes, engine removal is required for timing cover and cylinder head removal on the 2GR. It is actually fairly easy to drop the engine out of the bottom as long as you have access to a lift. It only takes about 2 hours.
     
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  14. Tombukt2

    Tombukt2 Active Member

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    They don't recommend machining because that thick nice person permanent torque head gasket will take up quite a bit of the issue . Or they used to .

    SM-A715F ?
     
  15. Tombukt2

    Tombukt2 Active Member

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    I've an old LS Starter surface plate on a stand here in old shop sposed to be flat to single tenths 1/10.000 of an inch at 75 degrees . It hasn't been certified in over 40 years but it also hasn't been moved if I remember correctly from my machine shop days these have to be certified every few years from my Pratt & Whitney days memory serves me well which it may well not

    SM-A715F ?
     
  16. Tombukt2

    Tombukt2 Active Member

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    Velcro used to make really nice copper shims just for this application for certain overhead valve engines that this was common to happen to like the 22REC Datsun l20B etc. Not sure if they still do anymore or it's been many years

    SM-A715F ?
     
  17. The Critic

    The Critic Resident Critic

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    They do not recommend machining because it may cause timing issues.
     
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