Jax White TA

I am still trying to find the source of my tapping sound that was in the motor before I started my hunt for it. I am down to the heads being off and still nothing. Some people are telling me that it might be a rod bearing that was knocking. Well, before I tore her down, I hooked up the atap and free revved the motor to past 4K looking for knock and found none. Wouldn't a bad rod bearing that was knocking cause knock retard?
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

steve

yes and no...

depends on how much of a "knock" the sensor is picking up.

how is your oil pressure? let us know some of the symptoms like does it do it cold or just hot. or both.

it could be piston slap ect....

steve frank

zombiedude

iTrader: (1)

Unless it was toast, you wouldn't 'here' a rod knock 'spining over w/heads on let alone off. But since you got it down that far, inspect the bottom end any way. couldn't hert. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

rich

Was it worse when it was cold or the same? My 2000 SS had cold piston slap real bad after two years of abuse. The dealer was going to do a piston update. Whan they tore it apart ther was a 3/4" wide stripe on the inside (towards the lifters)of the cylinder left bank only all four cylinders from the top to the bottom. It looked like the final bore wasn't large enough to make the cylinder perfectly round. You could tell the rings never seated in that stripe. So they replaced the complete long block. Your noise could be lifters, wrist pin, piston slap or rod knock to name a few.

cantdrv65

iTrader: (3)

I would tap the top of each piston lightly with a wood stick and hammer. If it is a spun bearing you'll more than likely here a different sound from the piston rod assembly of the suspect. If you don't find anything I'd probably inspect from the bottom anyway. You've come this far why not make sure?

Jax White TA

It knocked/tapped all the time no matter the temp. I found a sliver of sheared metal on the oil drain plug. It looked like when you slice cheese and it curls up real tight. I guess I'm going to pull the motor to see what it is. The lifters, pushrods, cylinder walls, pistons, heads, and valves all look good. I guess I'll yank the shortblock out too. Good time to do that new clutch install anyways.

Nine Ball

iTrader: (38)

Knock Sensors don't work that way. They are set to listen for specific frequencies which are determined to represent knock. They don't pick up all sounds, just ones that generate that frequency range they are tuned to listen for. Unfortunately, several things can generate this freqency and cause false knock. Not all noises can though.

Tony