So for the 2nd time i blew a head gasket on my 06 r53. Both times i had the head checked and surfaced. Prob a total of .025-.030 has been took off the head. IMO im ok with that because more compression equals more power. But A quick run down of mods. So after the first time i blew it i ported the head and intake. After running for a while i did a 17% pulley. One ball mod. Gutted the 2nd cat and tried to on the first but ran out of time. And modified the airbox. Was hitting around 16-17lbs of boost. After the 2nd time i blew the head gasket they surfaced it again and took off about another .010-.015. I ported and cleaned up some of the other pieces and put it back together. Now its hitting 21-22lbs of boost. Ive tried different boost gages so thats ruled out. Only thing i can think of is maybe the first catt got plugged up when i blew the head gasket. Also i bought the car with a blown head gasket. And the 2nd time it blew the water pump started going out and leaking and i had to limp it home 40 miles. Took me 6 hours of stopping and refilling. Any ideas ?

 

So in short my timing chain tensioner collapsed and caused it to jump time. Got it back together and bam it’s back to 16lbs. Details... every time I did the head gasket I never took the bottom cover off. I just put it on tdc and put the cam to where it was. Lol. Also when I would be a cheap butt and run 87 it would ping when warm if I got on it any. Sooooooo I’m thinking I had the cam one tooth advanced. Because now it doesn’t ping and runs better even tho it’s hitting 7 lbs less. Lol

 

All the Cams, Cam Gears and Heads I've done, I've never removed the timing cover, never even put it to TDC.
Simply found the triangle on the gear and marked the chain there, never any issues.
Glad to see you found out what it was.