2010 DIY head gasket repair help in Madison, WI

Discussion in 'Gen 3 Prius Technical Discussion' started by makeitgo, Apr 29, 2020.

  1. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Good question; I've thought that myself. Maybe besides driving belts it's mass is needed?

    How about this: considering the lack of belts, could the torque spec for the bolt be drastically lower?

    I get the feeling part of the answer is: the less you change, the less you need to chase down the possible ramifications.
     
  2. makeitgo

    makeitgo New Member

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    Doing the head removal I see the timing chain colored link are not even close to the standard position. The engine has be running great with no interference when now when i hand turn the engine. The two cam sprocket marks look to be in the correct relative position. And i have not remove the chain tensioner yet. There are the normal three sets of colored links in the correct locations on this chain. I can only assume the the last time it was remove the installer just ignored the timing marks.

    Can I just go ahead with the head removal and reuse this chain if the colored links line up on the correct three marks?
     

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    #22 makeitgo, May 6, 2020
    Last edited: May 6, 2020
  3. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I'm very green at this, but I believe you should crank the engine over (socket and wrench on the bolt at end of crank shaft, until you do get the alignment right. It can take 2 or 3 go 'rounds of the chain. Then, lock the cams, with bits of shop towel pinched in the cam journals. For more info watch the videos:

    New head gasket replacement video from Gasket Masters | PriusChat
     
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  4. ASRDogman

    ASRDogman Senior Member

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    The links/chain don't always line up after the engine have been turning.
    It looks like the one on the right in the photo, is off one tooth.
    When you put it back together, just make sure all the marks and chain line up correctly.
    Then turn the engine over by hand twice(720 degrees) The timing marks SHOULD like up
    when it is at tdc. Don't worry about the chain.
    Are the timing marks on the sprockets and crank where they are suppose to be?
     
  5. makeitgo

    makeitgo New Member

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    The colored link in the previous picture belongs over the rear camshaft mark. I don't understand how the chain can slip at all in a properly running engine?

    I'll do a basic check of chain wear and do normal manual specified installation.

    To take the fuel rail (with injectors) off the head do I really need to relieve fuel line pressure back at the fuel pump? Other videos suggest I can just disconnect the fuel line in the engine compartment.

    Thanks everyone for helping me to this point. 20200506_175932_copy_1024x562.jpg
     
    #25 makeitgo, May 6, 2020
    Last edited: May 6, 2020
  6. ASRDogman

    ASRDogman Senior Member

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    The fuel rail is under high pressure. If you release it at the connection, wrap a rag around
    it so it doesn't spray in your face.

    Those colored links are used for ease of alignment when installing. As you rotate the engine, they will be
    in different spots when you line up the marks. It doesn't mean the chain has slipped, or stretched.

    The important thing is to make sure the crank is at tdc, and the camshafts are on their marks when you install
    the chain. Then you place the colored links on the marks. The cams will rotate because of the lobs on
    the valves. So you have to rotate them to get the chain on. That's what the colored links are for.
    So when you have it on correctly, and put the tension in and release it. Everything should be in the correct position.
    Then you turn the crank clockwise as you are looking at it twice, 720 degrees. All the timing marks SHOULD
    be in the correct position. The colored links may or may not be. But it doesn't matter.

     
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  7. makeitgo

    makeitgo New Member

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    The head is off to the machine shop.

    Is there a good degreaser for the engine compartment? Don't have a power washer.
     

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  8. ttou68

    ttou68 Active Member

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    I pretty much use brake clean for everything when I replaced head gasket on my fix upper, but I also used throttle body and intake cleaner after I have ran out of brake clean and it seems to do a much better job cleaning the gunk off...

    Posted via the PriusChat mobile app.
     
    #28 ttou68, May 7, 2020
    Last edited: May 8, 2020
  9. Montgomery

    Montgomery Senior Member

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    I use an empty spray bottle, one part liquid Mr. Clean, 2 parts water. Spray, and rinse. I do that only when I encounter a car who's engine has never been cleaned. Afterwards, every 2 months, Mist spray (gently cycle) at the local do it yourself car wash.
     
  10. ASRDogman

    ASRDogman Senior Member

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    Cover the pistons. Then spray gunk, the flammable version, scrub any built up grease or grim.
    Let it soak 5-10 minutes, then hose off.
     
  11. makeitgo

    makeitgo New Member

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    Hi. I'm reassembling and trying to set the timing. Engine is at TDC and cams are in the same fixed position (using the shop towel clamp down trick) as when I removed the timing chain. I am putting on a new timing chain and the cam colored links are not lining up with cam marks, off by two teeth! Do I simply hand rotate one or both cams a bit to allow line up of the cam marks and crank mark with the chain color links? How precise do I have to be at this point? Will the engine run OK, does the VVT take care of that?
     

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  12. makeitgo

    makeitgo New Member

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    Hi ASRDogman.

    You've been helping me along the way. Maybe you can chime in in my last post where I'm having timing chain install problems. Seems like the cams where not quite aligned originally and now I have to fix that.

    Thanks,

    Rob
     
  13. ASRDogman

    ASRDogman Senior Member

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    Because the valves/springs will push on the lobs, it rotates the camshaft.
    So you have to rotate the camshaft into the correct position, hold it there, then install the chain.
    3 hands usually works. :) 4 is better. But you can do it by yourself. Just go slow, and be patient.
    You'll probably have to do it for both of them.
    When you get the chain lined up with the sprockets, check the crank sprocket.
    Make sure everything is lined up, then press the chain in where the tensioner goes.
    Then make sure everything is where it is suppose to be.
    Then install the tensioner. Then rotate the engine 720 degrees, two complete rotations.
    Everything should line up, again. If I am understanding others that have done it.

    You should not have much resistance (no spark plugs yet).

     
  14. ChapmanF

    ChapmanF Senior Member

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    No; they were on the marks when installed. Because the tooth count of the sprockets does not divide exactly into the link count of the chain, they won't always be on the marks every time you look. If you crank the engine around to see those marks come back around the right number of times, they will be on the marks again.

    We did the math for the 1NZ engine a year ago (used in Gen 1 and Gen 2 cars, and the c) and in that engine, it works out that the colored links will be on the marks every ninth time you see them. (So if the engine just turned off in some random position, on average you won't have to bring them around again quite five times to see them aligned.)

    I haven't seen anybody work it out for real for the 2ZR engine yet, but you could, either by counting the chain links so we can do the math, or just by cranking the engine around enough times to see the colored links line up once, and then count how many times you see them again before the next time they line up.

    When assembling, you must be precise. ASRDogman gave a good procedure in #26.
     
  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    The gasket masters trick, at the outset is to rotate the crankshaft until the marks and painted links do match up, then remove one of the cam journals, lay a 3 layer strip of shop towel atop the cam bearing, and reinstall the journal, torqued down enough to firmly lock the cam shafts from rotating.

    At this juncture I'm not sure how you reverse engineer that, not enough brain cells. But it must be doable.

    The attachment might help:
     

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  16. ASRDogman

    ASRDogman Senior Member

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    I did mean the timing marks, not the colored links. I should have explained better.
    Which I did earlier. :)
     
  17. ChapmanF

    ChapmanF Senior Member

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    I think they're removing a cam bearing. Removing a cam journal sounds fatal (not to you, but to the cam)....
     
  18. 2012 Prius v wagon 3

    2012 Prius v wagon 3 Active Member

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    Probably the "camshaft bearing cap." Sounds like it should work. When I need to keep a chain in the right spot on a sprocket, I try to use zip ties if there is a hole in the sprocket. Also liberal use of white-out to mark alignment of everything before disassembly helps. I might use all 3 of these methods, in addition to cycling enough times to get the colored links in place, when I eventually need to do this job.
     
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  19. makeitgo

    makeitgo New Member

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    How do I exactly position the two cams before placing the timing chain? I I understand the exhaust cam "E" and "I" dots are to be aligned with the head joint but I cannot view them directly with the angles in the engine bay. Then the intake cam ( Gen 3 VVT) has no marks except for the extended line that the chain colored link is set on. That line is supposed to measure +39 degrees from vertical at a TDC which is not something I can measure easily. How would you go about positioning the two cams before placing the timing chain?
     
  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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