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No Compression, Help!

charleswm94charleswm94 Member Posts: 2
edited December 2016 in Audi
I have a 2003 Audi A6 Quattro 3.0L V6 with no compression. The Timing belt broke Frown. I understand that this car has an interference engine and that it has a 99% chance to bend valves. Moreover, I removed the front bumper, radiator, valve cover assembly. I removed the spark plugs to check to see if any of the pistons had broke. None seem broke. The valves themselves are still going up and down freely, they don't seem to have bent. I bought the timing chain kit and the special tools to realign the camshafts and the crank, I then replaced the timing belt and water pump. Everything thing else is still off: front bumper, radiator, valve cover assembly, ac unit, and serpentine belt. The car still has no compression. If the crankshaft is out of time by 1 or 2 teeth could this cause the car to have no compression? Also, the exhaust valves on both heads are flush with the top of valve cylinders. The intake valves on both heads (the ones closest to the manifold on top of the block) sit slightly above the top of the valve cylinders. Both heads seem identical in relation to how the valves are placed. I try to turn the car over, and everything turns as it should, nothing seems to be clicking or hitting, but still no compression? Any Help? Things to check??


  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    edited December 2016
    How are you testing compression? It seems like if you have 0 compression all around, then the valves are most certainly bent.

    The best way to solve this is to do a cylinder leakdown test or pull the heads.

    Maybe THIS VIDEO will give you some tips on engine timing.
  • charleswm94charleswm94 Member Posts: 2
    I pulled the spark plugs and just used a normal compression test
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You should be able to verify that the cams and crank are synchronized and yes a car will run if you're off one tooth and it should run, although badly, if you were off two teeth. Three teeth? Probably not.

  • charleswm94charleswm94 Member Posts: 2
    Ok, thanks very much! I'll update if I get this fixed.
  • thecardoc3thecardoc3 Member Posts: 5,747
    If the crankshaft/ camshaft timing is out three teeth the engine would still develop some compression, not enough to meet normal specifications but some. To make no compression at all, the valves have to be open. A cylinder leakage test would be in order to confirm if the valves are sealing or not. If you cannot run that test here is a little trick you can try. Using your hand, block off the throttle body restricting the airflow like the throttle does. Now have an assistant crank the engine and see if you can feel suction. (If the engine uses an idle air control separate from the throttle body, block that off too. )

    If you feel suction, then you have more testing to do, but if you don't feel any vacuum at all, then the valves are probably bent.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    The valves can be bent and still move up and down.
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