Slight marble knock on top of engine HELP !

[KWIKR 1]

I've been trying to chase down a low boost knock problem with my newly rebuilt engine . I happened to be under the hood, and gave the engine a couple of good "blips" on the throttle . I can hear a "slight quick marble knock" on the top end of engine when the engine is reved quickly . Sounds like it's comming from the valve train . Engine has a fairly new cam sensor in it , so I'm ruling that out . Any comments ? thanks.

 

[Red Regal T]

I'M PRETTY SURE THE NOISE YOU HAVE IS THE SAME I HAVE ON MY CAR. DEFINITELY VALVE TRAIN RELATED. PROBABLY LIFTER NOISE. I'VE HAD THIS NOISE FOR MILES AND MILES. I'M RUNNING 22#S OF BOOST WITH NO PROBLEMS.

 

[KWIKR 1]

Red Regal T , what kind of knock numbers are you getting on your scan tool ? Would the knock sensor pick it up and pulling the timing out ? Everything is this engine is brand new including the Comp Cams roller lifters . Could this be a lifter preload problem ?

 

[Black Box]

Is the wategate puck seating against the hole? My THDP puck rattled until I tightened it up 1/2 a turn or so. I had the WG rod too loose.

Steve

 

[KWIKR 1]

I just finished pulling off the PS valve cover and notice "part" (about 1/8 from the side) of the plastic button on cyl 2 exh that holds the rockers in place is missing . Would this be enough to cause a knock noise ? there seems to be alot of side to side movment in the rocker because of this . .

 

[KWIKR 1]

I just found two more buttons with the same problem on the DS . This can not be right . Has anybody else seen GM buttons that were not completely round ? thanks.

 

[Red Regal T]

I JUST CHANGED MY ROCKER SHAFTS AND DID NOT AFFECT THIS NOISE. ALL I KNOW IS MY CAR HAS A SLIGHT MARBLY SOUND AT LOW RPMS. DON'T NOTICE IT ALL THE TIME. DOESN'T AFFECT KNOCK. HEAR NO NOISE WHEN I'M AT WOT.

 

[KWIKR 1]

This is a high rpm marble knock when you give the throttle a good blip . My shaft and rocker arms, GM retainers are brand new . my question is will this odd shape nylon rocker arm retainer cause the the rocker arm to knock at high rpm ? thanks.

 

[Red Regal T]

SORRY, I THOUGHT YOU WERE TALKING A LOW RPM PROBLEM. IS THIS A NEW BOTTOM END. POSSIBILITY OF ROD BEARING NOISE. DOES IT MAKE THE NOISE RIGHT BEFORE IT SHIFTS? ALSO, IF YOU GET A RAP AT THE END OF QUICK REVS, SOUNDS LIKE ROD BEARINGS.

 

[KWIKR 1]

it's a new rebuild . and the rap is in the middle of throttle blip . I'll email you a scan of the nylon retainer . thanks

 

[Granny 2]

I have a knock too at 2,000 rpm only under load. I can't here it just buy reving in neutral. I think it is a lifter knock. Any other ideas??