...it started running extremely rough. it sounded similar to a clunking noise from engine, rpms slowed and killed the idle twice. its not a thrown bearing sound, i'm pretty sure of that. but i was trying to re-adjust the rockers now for my first time when it did this. it kind of freaks me out a bit and want to know if i did something wrong before i keep going. everything looks okay from the under the valve cover prospective. any tips on what might have happened. i was using the screwdriver method to listen to the valve as i loosened the nut and then tightened it till it quit making noise. i only have done two so far. could i have over tightened them causing it to do this? thanks for any help.

 

If you overtighten the rockers it will kill the engine. With pro mags finger tight should be very close to zero lash then just set your preload.

 

okay, i loosened them a bit. enough to where i can keep it going. but the sound of metal clunk or clack is coming from the engine. i'm not sure what it is, but that noise is whats scaring me. like i said, it doesnt sound like a thrown bearing, but i cant place the sound exactly. and it is pretty loud. is there any way i caused this by adjusting a rocker? it keeps pace with the engine rpms. i checked the driver side valley and it seems that all pushrods are on the lifters. this is the only side i have taken off. i guess ill take off the passenger side to to get a peek at what that side is doing. whatever it is, i dont want to keep the engine running until i figure out what it is.

 

The idle should slow a bit and then pick back up as you set each rocker.. that is my experience anyway. Even with open headers I didnt need any screwdriver to listen. Just unscrewed the nut till it clacked then tighten it down with my fingers till the noise goes away and finished off with a 1/4 turn on stock lifters.

If you have those comp R lifters then you arent supposed to really set them more than 1/8th turn past "0" lash. If you did that might drop the idle enough to stall the motor.

 

okay, that sounds about like what i was doing. any clue as to what would/is causing the metal clunk sound that i am now hearing. it is a lot louder and sounds like it comes from the engine itself. not the rockers. could i have collapsed a lifter by finger tightening the rockers? i do have new comp cams lifters and pro mag rockers.

 

okay, the loud sound is coming from my intake i assume. i turned the car back on to trace the sound and it sounds loudest underneath my car, coming out of my air filter. i can change the variation/frequency of the loud sound by loosening and tightening the rockers slightly. but i have yet to get it to go away.

 

Has your oil pressure dropped at all? Is it at a constant reading even when rpm increase. I know you said it didn't "sound" like a spun bearing. I spun a main in my old truck and the oil psi stayed at 20 psi, never increasing no matter where the rpm went.
I had a wrist pin fail , on purpose, I was going to rebuild my Monte SS and blew up the crappy truck motor someone else had in it. I had a different block so I was hoping for catastrophe, but after standing on the gas for almost 1 minute wide open, the pin finally let go. It made a hell of a clanging. The piston skirt shattered and was in the oil pan after ward, no more oil pressure and the rod tore up the bore horribly. Weird thing was, you could hardly tell it was down a cylinder from the idle. The piston, what was left, was hammered into the head and chewed up by the spark plug. The head was junk also, as I couldn't even get the spark plug out!
I am not trying to scare you , but if it is the rod you WILL know it. It makes a horrible sound thrashing in the bore

 

phew, thanks for the replies all. and might i recommend everyone check over their work once they put together a new engine. the noise was coming from a rocker on the number 7 piston intake side that had managed to loosen itself almost to the point that it was about to fall off. i dont know if i just missed the poly lock on that one or what? i hadnt touched it at all when doing my rocker adjustment just now. i decided to go through all of them and found the nut on that one barely threaded on. i set it to zero lash manually (without engine running) plus 1/10 and locked it down tight! oh thank god!!! i was scared for a second there that it was possibly a bearing. i have restarted the car and it seems perfect now. not a single rocker clack. so did i get away lucky on this one or could there be another problem that this might have caused?

btw-lifter and pushrod look fine on that cylinder.

 

hey we will have to get together when I get back home Id like to see your car I will have the 383 LT4 thirdgen I live in FWB ill be putting my engine together in May as soon as I get back from Iraq

 

yeah, definitely give me a holler. i wouldnt mind seeing that monster lt4 put together. i wouldnt mind lending a hand also if you need some help.

BTW- hows the weather over there? its still pretty nice and cool over here. oh, and your totally missing spring break...

 

yeah the weather sucks cold and rainy then hot during the day we get to play the HVAC wars crank the AC during the day but freeze at night or crank the heat and sweat ***** during the day its always one way or the other in my tent

I pm you when i get back and thanks I KNOW IM MISSING SPRING BREAK but ill be there all summer and next year too

 

If I get my heads/cam installed by someone and all of the stuff needed for it, how do I know they did the right thing? How will I know if my rockers are too tight/loose? When I get this done I'm going to ask if they can take all the stuff out and put it in a box so I know they did the work instead of ripping me off, and maybe sell some of the old parts. How much does a good set of pistons cost with connecting rods?

I wanna make sure I get the good work done to my car