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ok so here's the full story... i noticed louder than normal valve-train/engine noises. almost coming and going in a rhythmic pattern. i didnt like the sound of it and parked it, and right before i shut it down it started making some horrible noises . i borrowed my friends compression tester and tested Cyl#6 first turning it over with the starter a few times. got to about 149ish PSI. while it was rotating it still didn't sound good. i then proceeded to check the other 5 cylinders... NO COMPRESSION what so ever and now #6 wont get compression anymore. and now the bad noises from before are gone when turning over. i put all the plugs back in except #1 and the starter still turned over the engine with no resistance. everything is spinning together, crank, both cams. i even placed a long screw driver down the #1 plug hole to make sure the piston was actually moving and it was. i'm thinking my timing is WAAAAYY off? maybe? but then why did i get compression that first time around in #6 and now nothing? i have 2 videos... the first vid is when i initially tested #6 and got compression and the second is when i had all the plugs in and turned it over. WTF is wrong!?!?!?! :confused:
 

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When was it last serviced and who was the last to do any kind of engine work on the car?

Take it back to them if any work was done recently.
 

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My guess would be as above, the initial horrible noise was valves touching piston / other valves due to timing slip. It then slipped further and all bent to the point it doesn't touch anymore giving no compression.

You might be lucky and get away with only replacing valves/ guides as it may have fallen off as you shut the engine down
 

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Could the head have lifted apart from the cylinder which has compression?

or would that be very obvious from smoke? mayonnaise? etc
only ever seen a head lift due to too much boost and failed head studs

i do reckon the noise was the timing belt tensioner failing and now the timing is so far off it has no compression
 
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