difference between rod knock, and valve knock?

dank24

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#1
Alright I am starting to think maybe I have a rod knock. I have no idea of telling. When I rev up the sound gets faster. Is there a way of telling the difference?
 

orfus5

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#2
listen at the top of the car then at the bottom, see which end its coming from more.
 


Matt.

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#4
orfus5 said:
listen at the top of the car then at the bottom, see which end its coming from more.
Thats not going to do much but give different aspects of the sound.

As I told you in IM, I really doubt its a rod knock from hydrolock.
 


vandynamics

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#5
have the motor running and in knock conditions. then get brave and pull off the spark plug wire for each cylinder. it will be 4 different tests. one for each cylinder.

if when you pull the wire out (which in turn relieves force off of the rod) and the knock goes away, not only have you pin-pointed the knock. but youve pin-pointed the cylinder # thats causing it.

but in general, valve sounds are much lighter than the thumping, almost shaking, rod knock sounds.
 

vandynamics

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#6
Blahman240 said:
Thats not going to do much but give different aspects of the sound.

As I told you in IM, I really doubt its a rod knock from hydrolock.
a hydrolock will have no problem causing a rod knock. s**t, i bent 3 piston connecting rods with a simple "hydrolock"
 

dank24

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#7
oilpool said:
have the motor running and in knock conditions. then get brave and pull off the spark plug wire for each cylinder. it will be 4 different tests. one for each cylinder.

if when you pull the wire out (which in turn relieves force off of the rod) and the knock goes away, not only have you pin-pointed the knock. but youve pin-pointed the cylinder # thats causing it.

but in general, valve sounds are much lighter than the thumping, almost shaking, rod knock sounds.
thanks dude, for real. I am going to try this now
 

dank24

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#8
just tried it. didn't really go away, just the idle went down.
 




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