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Bad top end noise after head gasket repair

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  • Bad top end noise after head gasket repair

    I have a '95 Grand Prix with the 3.4 DOHC. I purchased this car with a blown head gasket. I just got it put back together tonight and the lifters i assume are making a horrible racket and it will not go away. Also it cranks like the timing is advanced (really pronounced speed reduction on every compression stroke and backfires and rotates the engine backward). I double checked the timing gear/intermediate gear alignments and it looks good unless i just am doing it wrong.. I installed the belt with #1 cylinder at TDC, balancer mark aligned with cover mark, both cam flats facing up on both heads.

    I'm trying to figure out what i could have forgot to plug in that would cause this hard cranking condition. And i'm at a loss for the massive amount of noise on the top end. Oil light does not come on (not that i'm sure it works), but there is oil getting up to the cam carrier.

    When it is running it seems to be running pretty smooth with the exception of when you give it gas there is some "bogging". Any help would be greatly appreciated.

    Thank You!!

  • #2
    If i were to be off a tooth on the front intake cam ( looks like where the cam sensor reads ) Could that cause the ignition timing issue? I assume the cam sensor is only used for sequential fuel injection and not spark timing?

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    • #3
      Originally posted by WoR473 View Post
      I have a '95 Grand Prix with the 3.4 DOHC. I purchased this car with a blown head gasket. I just got it put back together tonight and the lifters i assume are making a horrible racket and it will not go away.
      While this may not be the cause, did you check to see if your engine complies with GM bulletin 57-61-09 "Lifter tick when cold"?

      http://60degreev6.com/forum/showthre...ick-%28cold%29


      Originally posted by WoR473 View Post
      Also it cranks like the timing is advanced (really pronounced speed reduction on every compression stroke and backfires and rotates the engine backward). I double checked the timing gear/intermediate gear alignments and it looks good unless i just am doing it wrong.. I installed the belt with #1 cylinder at TDC, balancer mark aligned with cover mark, both cam flats facing up on both heads.
      Did you rotate the crankshaft one revolution to get the cam flats in the proper synch with the crank for the front bank (2, 4, 6)? If not, I bet you now have a double-three cylinder rather than a proper six-cylinder. With two cylinders going to TDC compression at the same time, the starter will be over-worked, as will the ignition system. I've heard of this happening, and the results were about what you describe--although I don't remember a "noisy lifter" complaint. Rough running, and hard-starting were mentioned.

      Originally posted by WoR473 View Post
      Oil light does not come on (not that i'm sure it works),
      Of course you know that the light works...it comes on when the key is on, but the engine isn't running...right?

      Originally posted by WoR473 View Post
      If i were to be off a tooth on the front intake cam ( looks like where the cam sensor reads ) Could that cause the ignition timing issue? I assume the cam sensor is only used for sequential fuel injection and not spark timing?
      If ANY of the cams aren't timed properly, sure, you're going to have engine driveability problems. Sorry, I don't know if the ECM gets spark-timing info from the cam or from the crank sensor...or both.






      Please tell us that you replaced BOTH head gaskets. When my Lumina popped the gasket between #1 and #3 and pressurized the cooling system, I also found the front-bank gasket in the process of failing between #4 and #6. I believe the cylinder head is weak in that area, leading to the head deck-surface collapsing and losing clamping force on the fire-ring of the gasket. I had to replace both gaskets, and SHAVE THE HEAD .015 to restore flatness.
      Last edited by Schurkey; 03-21-2016, 12:57 PM.
      ^ some people may call this guy an asshole at times, but he isn't wrong very often -- Robert

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      • #4
        Originally posted by Schurkey View Post
        Did you rotate the crankshaft one revolution to get the cam flats in the proper synch with the crank for the front bank (2, 4, 6)?
        OMG, that's it... I don't know how i missed that. Embarrassing lol

        So let me get this right, you install the cam holing tool, loosen the cam gear bolts, install the belt with the #1 at tdc, tighten the rear bank cam gears, rotate the crank one revolution, then tighten up the front bank cam gears?

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        • #5
          Yes i did replace both head gaskets, i couldn't see tearing it down that far and not doing it.

          And i thank you sir for that very informative reply, It is much appreciated!

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          • #6
            In essence, yes. Of course, the front cam gears/sprockets have to be loose so the belt and sprockets can turn (because the belt is already installed) yet the front cams don't turn when you roll the crank that one revolution.

            Curious: Were your head gaskets both bad, and were they bad in the same place as the ones in the photos? Did you plane the heads?
            ^ some people may call this guy an asshole at times, but he isn't wrong very often -- Robert

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            • #7
              Just the rear bank was bad as far as i could tell and it was in a different spot. I'll try and get a pic in a few. Yes i did plane the heads and evidently they really needed it.

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