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Now what? (CAM broke off)

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  • #16
    That's just a lot of PCV build-up, probably running regular oil at extended intervals and a motor that had a bit of blowby.

    This is exactly why I don't run a PCV into the intake manifold, you're constantly sucking in nasty vapor under cruise with high vacuum.
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


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    • #17
      That's NOT a 500-mile motor. no way, no how.

      can you see the honing marks on the cylinder walls? I can't tell much from the photo, but it looks more like 50,000 miles than 500 miles on that block.
      Originally posted by SoSideways
      I don't care what color they are as long as they are LONG AND HARD.
      '04 G35 Sedan 6MT- The DD
      '96 240SX- The Track Toy

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      • #18
        That head looks more like 100,000 miles and a lack of maintenance.
        '18 Chevrolet Volt - Electric fun hatch for DD duty!


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        • #19
          Okay, okay, let me explain in more detail. The motor was rebuilt 500 miles ago. New piston rings, honed cylinder walls, new bearings, resurfaced head, new valve stem seals, and probably few more things I am forgetting. It has not gone through a single oil change since the rebuild. I was planning on changing the oil at a 1000 mile mark.

          Gradually it took longer and longer to start when cold. While doing a compression check to verify the health of the engine, the intake camshaft snapped. The rest of the story is in the beginning of the thread.

          I can definitely tell you that the pistons, intake side of the head, and the intake manifold did not look anything like they do right now when I've installed the engine. Just a month ago it was all nice and clean.

          So this couldn't have been caused by bad gas?
          Attached Files
          Last edited by Rovch; 06-04-2014, 08:06 PM.

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          • #20
            Bad gas shouldn't/wouldn't do that. sounds like you had a bad bearing or something stuck in an oil galley somewhere and that cam started locking up due to lack of lubrication.
            Originally posted by SoSideways
            I don't care what color they are as long as they are LONG AND HARD.
            '04 G35 Sedan 6MT- The DD
            '96 240SX- The Track Toy

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            • #21
              Originally posted by Rovch View Post
              Okay, okay, let me explain in more detail. The motor was rebuilt 500 miles ago. New piston rings, honed cylinder walls, new bearings, resurfaced head, new valve stem seals, and probably few more things I am forgetting. It has not gone through a single oil change since the rebuild. I was planning on changing the oil at a 1000 mile mark.
              All I see if that they used a little degreaser and a brush on the outside to clean it... as mentioned, you are not going to get soot and oil crusties like that fast, even from running rich with a stuck open egr, that took time to deposit

              If that's a "rebuilt" head, I would assume they didn't do half of what they said, maybe changes a few bad parts after checking, they probably "resurfaced" the head with a scrub pad
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              • #22
                Originally posted by Matt93SE View Post
                Bad gas shouldn't/wouldn't do that. sounds like you had a bad bearing or something stuck in an oil galley somewhere and that cam started locking up due to lack of lubrication.
                If gas isn't an issue, what could have cause that much build up so quickly?
                Can faulty PCV cause something like this within 500 miles?

                I understand that build up does not relate to the cam snapping, but I still have to fix it.

                Initially (when CAM snapped), I've removed both CAMs & upper chain, then cranked the engine to make sure CAM was getting oil - which it did. Cam was also very clean on the inside. Although lack of lubrication sounds like a possible cause, I did not find any evidence.

                Originally posted by G-E
                All I see if that they used a little degreaser and a brush on the outside to clean it... as mentioned, you are not going to get soot and oil crusties like that fast, even from running rich with a stuck open egr, that took time to deposit

                If that's a "rebuilt" head, I would assume they didn't do half of what they said, maybe changes a few bad parts after checking, they probably "resurfaced" the head with a scrub pad
                Well all that nasty build up has happened within 500 miles. Chambers on the intake side of the head and IM did not have any major buildup when I've installed it. What you see is literally 500 miles down the road.

                Better pictures (first - 4 intake chambers; second - top end & exhaust side):


                Last edited by Rovch; 06-05-2014, 12:29 PM.

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                • #23
                  I don't possibly see how that's just in 500 miles. Looks like thousands and thousands of miles of build up.

                  I'd change your PCV and check your intake piping for tons of oil.
                  '18 Chevrolet Volt - Electric fun hatch for DD duty!


                  DefSport Koni Sleeve and Spring Perch Buy!!!
                  http://www.nissanroadracing.com/showthread.php?t=5902

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                  • #24
                    Originally posted by Def View Post
                    I don't possibly see how that's just in 500 miles. Looks like thousands and thousands of miles of build up.

                    I'd change your PCV and check your intake piping for tons of oil.
                    Neither can I, but it's there. And it feels nothing like your normal buildup on high mileage engines. This stuff is hard and shiny like candy (no pun intended). It does not want to come off very easily.

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                    • #25
                      I almost wonder about bad fuel in that case... someone sugar'd your gas tank?
                      Originally posted by SoSideways
                      I don't care what color they are as long as they are LONG AND HARD.
                      '04 G35 Sedan 6MT- The DD
                      '96 240SX- The Track Toy

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                      • #26
                        WTF? didiyou mistakenly put epoxy or lacquer in the gas tank....nothing else should build up that hard and fast ive never seen even a 130,000 mile motor look that bad
                        I am SKULLWORKS

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                        • #27
                          Originally posted by Matt93SE View Post
                          I almost wonder about bad fuel in that case... someone sugar'd your gas tank?
                          I hope not.

                          Originally posted by Tower240sx View Post
                          WTF? didiyou mistakenly put epoxy or lacquer in the gas tank....nothing else should build up that hard and fast ive never seen even a 130,000 mile motor look that bad
                          I got the car in non running condition. Unless previous owner did something stupid, there should be nothing but gas.

                          Machine shop told me that apparently ethanol in gas can do that after sitting for a while (when I dropped the head off). Apparently I am not the first one.

                          Is there an acid that would be safe to use on the intake manifold to clean it on the inside (to submerge it in)? I really don't feel like scrubbing the insides with a brush and carb cleaner. This stuff is pretty tough to get off.

                          Not sure what to do about my fuel system either..

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                          • #28
                            Do you have the head off yet? (do you plan to take it off?)
                            Take it to machine shop and have them hot tank it. problem solved.

                            If the car was in non-running condition, there's no telling what was in the gas tank. it could be 5 yr old gas, it could be dead ants, diesel, who knows.
                            Originally posted by SoSideways
                            I don't care what color they are as long as they are LONG AND HARD.
                            '04 G35 Sedan 6MT- The DD
                            '96 240SX- The Track Toy

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                            • #29
                              Originally posted by Matt93SE View Post
                              Do you have the head off yet? (do you plan to take it off?)
                              Take it to machine shop and have them hot tank it. problem solved.

                              If the car was in non-running condition, there's no telling what was in the gas tank. it could be 5 yr old gas, it could be dead ants, diesel, who knows.
                              Yes, the head is already at the machine shop since Thursday. Waiting on the call back after hot tank and pressure check.

                              I was asking about the intake manifold... Not the head. IM has just as much nasty built up on the inside around injector/PCV area and I'd rather let it dissolve in some acid instead of scrubbing it with a brush. Maybe I'll take it down to the machine shop to see if they'll hot tank it as well.

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                              • #30
                                Yeah definitely. Its just a hunk of aluminum. They can tank it just like the head. Just pull all the sensors off first. Might as well gut the emissions crap if you haven't already.
                                Originally posted by SoSideways
                                I don't care what color they are as long as they are LONG AND HARD.
                                '04 G35 Sedan 6MT- The DD
                                '96 240SX- The Track Toy

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