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ever wondered what the inside of a duramax looks like?

Discussion in 'Heavy Equipment & Pavement' started by westcoh, Mar 19, 2011.

  1. westcoh

    westcoh LawnSite Senior Member
    from Alberta
    Messages: 313

    Thought you guys might find these pics interesting. I blew a headgasket on my 05 duramax and am in the middle of tearing it apart. Got the heads off today and took some pics. Apparently the star pattern on the top of the pistons is the injector spray pattern. When it goes back together all the emissions junk is coming off. I'll take some pics later showing how much sludge it builds up in the intake manifolds.





  2. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Messages: 10,137

    Why is the star pattern darker on some pistons?
  3. westcoh

    westcoh LawnSite Senior Member
    from Alberta
    Messages: 313

    Not really sure, the 2 that have the most prominent star pattern is where the headgasket was blown so maybe that has something to do with it. According to gm the major cause of the star pattern is from adding tuners to the engine, and I've been running a 90hp tune for the last year or so.
  4. DirtMerchant

    DirtMerchant LawnSite Senior Member
    Messages: 787

    Gm's full of ****. If that's where your headgasket then that's were foreign material was getting into the engine and messing with your combustion leaving residue behind which is what you see. As far as the back two cylinders on both side having some, probably something to do to with the bad air flow, resulting in incomplete/incorrect combustion. They're likely where the egr gets dumped back into. I'm not sure on that motor off the top of my head
  5. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    Make sure you have the heads inspected before re-installing them.

    Friend of mine just had his in the shop with a blown head gasket and they checked the heads and they were warped badly enough that they couldn't be milled to spec.

    Ultimately he ended up having to get new heads.
  6. 74inchShovel

    74inchShovel LawnSite Member
    Messages: 108

    Is that an LB7 motor, and I'm curious about how many miles on it
  7. westcoh

    westcoh LawnSite Senior Member
    from Alberta
    Messages: 313

    No doubt gm is full of ****. Apparently they were using that as an excuse to deny warranty claims. I've seen pics of completely stock engines that have the same star pattern on the pistons.

    Taking the heads to a machine shop tomorrow. Hoping they'll have them ready within a few days so I can start putting this this thing back together.

    Engine is an lly with about 220,000km on it. Gotta say I feel sorry for anyone who works on these things for a living as there's no room in that engine compartment. Can't imagine what the newer ones are like with even more junk under the hood than mine.
  8. ForestCreekLandscaping

    ForestCreekLandscaping LawnSite Member
    from Ontario
    Messages: 12

    I hope your putting an aftermarket head gasket and arp head studs in...
  9. salopez

    salopez LawnSite Senior Member
    Messages: 271

    just had this re-build done... it was very pricey....but i am very happy with the results.
  10. westcoh

    westcoh LawnSite Senior Member
    from Alberta
    Messages: 313

    Few more pics: the heads after getting them back from the machine shop, and new headgaskets on.



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