LOUD Knocking Sound!!!/Rod Bearing?? (sound clip inside)
04-20-2009, 06:53 PM
#1
Staging Lane
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LOUD Knocking Sound!!!/Rod Bearing?? (sound clip inside) This noise literally happened overnight! Never over-reved my engine. Engine has 80,000 miles on it, stock bottom end, very well maintained.
Went to start my car, and it sounds like someone is in my engine banging away with a sledgehammer! Thought it was coming from the bellhousing area, because you could feel the knocking noise from the clutch pedal and shifter. Noise is the loudest when cold, increases with RPM's. Oil pressure is NORMAL, not flickering. Engine seems to be running normal, then again never actually drove car out of driveway with the loud noise.
So removed transmission/clutch, started motor with just the flywheel on and noise still there.....
Ran car without belt, noise still there, so its not the supercharger or accessories causing the noise.....
Ran engine, disconnected every spark plug wire one at a time to see if I could identify rod bearing for sure, nothing noise stayed the same......
Drained oil, very little shavings on magnet, to really see have to get a magnifying glass, looks like sludge in a way.....
Took off valve covers, no lose rocker arms or broken valve springs.......
The only thing left is BEARINGS!!!!
Right? What do you guys think? Anyone had a spun bearing sound so LOUD??
Heres a clip: http://s250.photobucket.com/albums/g...ckingNoise.flv
Went to start my car, and it sounds like someone is in my engine banging away with a sledgehammer! Thought it was coming from the bellhousing area, because you could feel the knocking noise from the clutch pedal and shifter. Noise is the loudest when cold, increases with RPM's. Oil pressure is NORMAL, not flickering. Engine seems to be running normal, then again never actually drove car out of driveway with the loud noise.
So removed transmission/clutch, started motor with just the flywheel on and noise still there.....
Ran car without belt, noise still there, so its not the supercharger or accessories causing the noise.....
Ran engine, disconnected every spark plug wire one at a time to see if I could identify rod bearing for sure, nothing noise stayed the same......
Drained oil, very little shavings on magnet, to really see have to get a magnifying glass, looks like sludge in a way.....
Took off valve covers, no lose rocker arms or broken valve springs.......
The only thing left is BEARINGS!!!!
Right? What do you guys think? Anyone had a spun bearing sound so LOUD??
Heres a clip: http://s250.photobucket.com/albums/g...ckingNoise.flv
Last edited by martinls1; 04-20-2009 at 07:08 PM.
04-24-2009, 07:16 PM
#4
Teching In
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holy crap dude....that def doesnt sound good....i just did a head and cam package in my car and still have some ticking so im trying to figure out my issue still...
does sound like a lifter my have fell apart and is rattling around...so i would start there...pull the supercharger off and send it to me so i can keep it maintained for you...
i would start with the valvecovers and go from there...
good luck
does sound like a lifter my have fell apart and is rattling around...so i would start there...pull the supercharger off and send it to me so i can keep it maintained for you...
i would start with the valvecovers and go from there...
good luck
04-24-2009, 07:20 PM
#5
TECH Junkie
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Sounds like perhaps a cracked lifter tray allowing the lifter to rotate....... Either that or a cracked flex plate. Look at the flexplate first if this is an auto car
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04-24-2009, 08:17 PM
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Staging Lane
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Listen to this LT1. Sounds like yours: http://www.youtube.com/watch?v=EodvVgyB5DE
Like I said before, I have the valve covers off and none of the rocker arms are loose.
I even took the timing chain cover off and everything looks good.
04-25-2009, 05:32 AM
#13
My guess would be a lifter. Take your valve covers back off and push down on the lifter side of the Rocker Arm and see if it goes down, I had two lifters that collapsed and it sounded somewhat similar. A knocking sound is so hard to tell what it is because there are so many things it could be. You never really know until you tear into it?
04-28-2009, 02:32 PM
#14
Staging Lane
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Update Well, were all wrong, that noise my friends is a bent rod in cylinder #7. The bottom of the piston was hitting the counterweight of the crank. I am so happy that I finally found the problem and also relieved that I didnt take out the engine for nothing! I guess my stock bottom end couldn't handle 7.5 lbs of boost!
Heres some pics
Heres some pics
??? 
