Spun Bearing, when does it "Knock"

Rickyll7

Member
Dec 16, 2005
718
4
19
If you spin a bearing, when does it knock? Does it only do it when the engine warms up? Or will it knock all the time. what about engine speed? Will it get louder with engine speed, or will it only do it at an idle?
 
The modular engines are pretty noisy in stock form....at start up on older engines you will get some ticking/knock from the front chain tensioners due to wear over time but will stop or barely hear them when the engine is warm......if your engine ticks from start up and ticks match the rpm of the engine....good chances it is a bearing or somthing in the valve train thats not right!

"ED"
 
i cracked one of my headers recently, i can hear, smell, and feel the hot exhaust leaking. I think this is whats causeing the noise. my headers are wrapped and i think it is the two cracked peices hitting each other. the headers probably cracked because they got too hot with the header wrap. it only does it when hot, and is a random knock, not consistent with rpms. and it only does it at an idle, when the engine is rocking back and fourth from my cams:D BTW, It runs like a champ!
Sound about right? or is there another possible cause?

edit: note that there are two noices, one is the exhaust leaking through the wrap, the other is the strange knocking noise.
 
svttech76 said:
Thats a spun bearing/rod knock noise. plus if you have a real oil presure gauge you will see the presure is jumping all over the place.

Damn... I wish you could've heard it in person, man. It sounded 1000000x's worse and hurt so bad to hear :(

Luckily it has been laid to rest. The new motor is on it's way to the shop, altho it's just another '02 GT motor.. This one has 33k miles, instead of my 73k mile motor.
 
Rickyll7 said:
Uh, yea. Have any ideas?
BTW, it sounds nothing like the video in here.
spun bearing sounds are never the same, sometimes they are consistant, and others they are heard above idle and not under load, sound is like a hammer tapping on a block of aluminum, I defiantely know your block was prone to that since shm has 17yr olds fresh out of highschool vo-tech buiding engines
 
Wow, I didnt know that. Well this is what it does...
random, (not consistent with rpms as in the video)
only at idle
but will usually not do it until it is warmed up
not loud at all like the video
about 1-2 seconds in between knocks
engine runs perfectly and strong
 
i think i got a spun bearing as well. i thought it was valve train related but i went through it like 3 times. i did find little metal shavings or flakes in the oil pan. rod or crank bearing?? it doesnt sound like jasonh_86's car but close to it. its not as loud but when i give it cas i really hear it. around 1500-2000 all the way up. it didnt start doing it at idle till i drove it for a little bit. but now when it warms up it ticks or clacks or however it sounds.
 
98armygt said:
i think i got a spun bearing as well. i thought it was valve train related but i went through it like 3 times. i did find little metal shavings or flakes in the oil pan. rod or crank bearing?? it doesnt sound like jasonh_86's car but close to it. its not as loud but when i give it cas i really hear it. around 1500-2000 all the way up. it didnt start doing it at idle till i drove it for a little bit. but now when it warms up it ticks or clacks or however it sounds.

metal in the oil = no bueno :(

If I were you I would drop the pan and look at the damage. Chances are your rods are fried though if it's already knocking. Time for a MMR900 shortblock or VT :nice:
 
i didnt notice the metal till i dropped the oil pan and it looked like someone threw confetti in there. i know i **** the bearings in that thing. so im gonna tear it down and start rebuilding back with stock parts. i plan on ordering a new short block from VT or MM come january to put back in the car. ill save the stock block just in case i break something else in the new one.