long story short i sucked paper towels from my upper intake into the cylinder head. i installed 19# injectors, set timing to 14*, and readjusted roller rockers. other mods are in the sig, injectors are now 19# NOT 24#
issue:
a loud, but muffled knock around the center of the motor loudest between cyl 1 and 5. car drives fine, idles perfect, tons of power. sound sometimes seems to come and go. when i was returning home from my test drive it got louder and constant. like a rattle, this time louder and less muffled sounded a lot like a loose rocker/detonating
things i have done to fix this: (NOT SINCE returning home from test drive. all of this fixes were before test drive)
1. removed lower and removed all the paper i could by opening the intake valve some
2. readjusted rockers many times (tighten rocker till i can not twist the rocker by the tips of my fingers then turn 1/4 turn. actually just by hand tighting the nut on each cyl TDC i got tension and the pushrod and went 1/4 turn with a wrench from there)
3. used a boroscope to look down the lower intake and spark plug hole of the cylinders, did not see anything that didnt belong
4. drove the car high and low rpms, fast and slow speeds
5. had my shopforman listen to it. he didnt know what it was.
my thoughs
1. a small piece of paper got its way into the oiling system and is blocking a passage somehow. this i kinda doubt because after a few minutes of hot oil at high rpms (high oil pressue) is should've busted up and moved on.
2. a small piece of rtv when cleaning the cylinder heads (i had towels covering the valley but maybe. same thoughs as piece of paper)
3. rockers may still be wrong doubt it
4. dumb luck, have a(many) bad lifter(s) and it just happened to show itself now
5. motor is detonating and retard timing or reinstall 24# injectors (it was running WAY rich with 24# injectors)
suggestions thoughts.
i think worst case would be i pull the motor and completely tear it down. clean all ports/passages, a little maching work to clean it up. new rings and bearings also. maybe DSS rebuild kit with forged pistons?
issue:
a loud, but muffled knock around the center of the motor loudest between cyl 1 and 5. car drives fine, idles perfect, tons of power. sound sometimes seems to come and go. when i was returning home from my test drive it got louder and constant. like a rattle, this time louder and less muffled sounded a lot like a loose rocker/detonating
things i have done to fix this: (NOT SINCE returning home from test drive. all of this fixes were before test drive)
1. removed lower and removed all the paper i could by opening the intake valve some
2. readjusted rockers many times (tighten rocker till i can not twist the rocker by the tips of my fingers then turn 1/4 turn. actually just by hand tighting the nut on each cyl TDC i got tension and the pushrod and went 1/4 turn with a wrench from there)
3. used a boroscope to look down the lower intake and spark plug hole of the cylinders, did not see anything that didnt belong
4. drove the car high and low rpms, fast and slow speeds
5. had my shopforman listen to it. he didnt know what it was.
my thoughs
1. a small piece of paper got its way into the oiling system and is blocking a passage somehow. this i kinda doubt because after a few minutes of hot oil at high rpms (high oil pressue) is should've busted up and moved on.
2. a small piece of rtv when cleaning the cylinder heads (i had towels covering the valley but maybe. same thoughs as piece of paper)
3. rockers may still be wrong doubt it
4. dumb luck, have a(many) bad lifter(s) and it just happened to show itself now
5. motor is detonating and retard timing or reinstall 24# injectors (it was running WAY rich with 24# injectors)
suggestions thoughts.
i think worst case would be i pull the motor and completely tear it down. clean all ports/passages, a little maching work to clean it up. new rings and bearings also. maybe DSS rebuild kit with forged pistons?
