Ok the noise is bad at idle but when throttle is given it goes away completly. There is no power loss as well when driving it. The noise sounds like it is coming from the oil pan. Well long story short i pulled the pan and noticed the oilpick up screen broke off and 2 nuts holding the windage tray backed off. Well got it all back together and still same noise. Checked the torque converter bolts and they are all tight. I dont think it can be a connecting rod. Also when i had the pan off i could move the (rod bearings?) at the bottom of crank slightly left and right. All of them moved the same distance in a left and right direction. Is this normal? Also if i had a spun bearing it would get worse throughout the rpm right? The engine is fairly new 355 fully forged lt1. It has around 12k miles on it. As i said earlier the power is still there throughout the rpms. I just cant figure out what this noise is. It can't be valvtrain either cause it sounds way louder from the bottom. Im thinking the stall could be going out or something. Just sounds like something is rattling around in there....Also there was no metal shavings or any type of metal during the oil change. The noise sounds like rocks/nuts in a coffee can rattling around.



Please let me know what you guys think?

http://www.youtube.com/watch?v=mr7766Zzivw (video is being processed right now but should be done shortly)

 

rod knock would be worse throughout the RPM range. the rods will move back and forth a small bit. Have to compensate for thermal expansion you know.

When did this start? Pretty bad to have an oil pickup screen broke off. Any idea on how that can happen? Did you mean SPECIFICALLY the screen or the whole pickup?

Checked your filter?

 

The screen completly broke off the pickup tube. It started after a stuck closed thermostat that started to overheat the car. I ended up seeing coolant in the tube that comes off the valve cover. So i put new heads on and had the heads resurfaced. Put everything back together and it went away for a bit but then came back after a good 15 minutes of running around town. Replaced the oil pump with a new one and used locktite this time on the windage tray nuts. I didnt use them last time and thats why they fell off. Which probably caused the screen to break off?


Anyways yea i figured a rod knock or spun bearing would be louder throughout the rpm range, but this dissappears. Which leads me to possibly be transmission as in stall?

 

Sounds to me like something got down on top of a piston. You said you got ne resurfaced heads, maybe something got into there when you did your install, or broke and found its way into there. Also did you recheck proper PR length when you put the new milled heads on?

 

The enigne made the same noise befor i took it apart. Pistons looked good. Nothing that looks like something would be scrapping it. The heads were fix professionally. So that is not an issue. The heads had the valves replaced. They are also stock heads with 1.6 roller rockers and .600 springs. It isnt coming from the top of the engine at all.

 

Could be a wrist pin slapping as well, noise travels through the block, use a piece of hose sort of like a stethoscope and try and isolate were it is at. If it were an issue with the piston or in that area it would be hard to tell where the noise it.

Other than the noise, a rod bearing would be showing other signs such as low oil pressure. When you took the heads apart there would have been shiny metal where the piston had contacted the head.

Just some thoughts you can lemme know what you have tried etc and I'll keep throwing them out there......

 

this sound is coming from the bottom of the motor for sure, you can feel the vibration/rattle in the oil pan. everything looked good when the motor was out. there was a little play in the rods but not too much i don't think. how much is normal? the noise doesn't go completely away when i idle up but definately decreases. it sounds like nuts and bolts getting shaken around in a coffee can. can a stall make this type of noise? i just need to get this thing fixed, any and all help is much appreciated

 

i didn't have the motor completely torn down, just down to a short block. i have good oil pressure, no power loss, no noise through the exhaust. when i got the motor back in it seemed to be ok, but after 20 min of driving i was sitting in burger king drive thru and this god awful rattle started. also when i turn the engine off right when it stops turning the knocking is the worst.

 

I just watched the video and it sounds like a rod knock to me. The play or clearance that is acceptable is .006-.014.

 

Yea but doesnt rod knock get louder or stay knocking with the rpm range? This sound goes away and it sounds like more of a rattle than a knock!

 

It depends on how the bearing is spun, it could have just worn material, or out of round rod and then you would get an intermittent slap/knock, or it could be spun and stacked and you will get it all the time. I have experienced both a constant and an intermittent rod knock and found it to be both ways, I am sure there are other possibilities as well. One of them affected oil pressure the other did not.

I am keeeping my fingers crossed for you that it is something else, but the likelihood is that it is not. Either way you are going to have to tear into her to find out what it is.

Was the assembly rebalanced prior to install?

Oh yeah and I was determined that it was my torque converter the one time....... did the same thing checking to see if the bolts were hitting etc and well.....it wasn't.

 

i was thinking of taking the stall out, buckling tranny back up and starting it

 

It's up to you It would be nice for once if it were something like that and its always worth a shot.

 

Why not just unbolt the converter and push it in a little to eliminate it as a problem? Check out the damper. I've seen a seperated balancer make noise only at idle. Probably a reach but worth looking into.

 

weird. definetely sounds like somethings about to give out