valvetrain

[skriFF]

My engine is making a pretty loud knocking noise coming from under the valve covers and nobody was really quite sure what was making the noise. So I finally removed my valve covers today. It was a huge pain in the @ss becuase of the upper intake manifold, the TB, fuel rail and fuel lines. Me and my dad worked on it and 2 hrs later we finally had them off.

We looked at all the rockers and pushrods and there didnt seem to be any visible damage to any of them. The rockers on cylinders number 2, 4, 5, and 6 were pretty loose so we tightened them. We also made sure that all the others were pretty snug.

After looking at the everything, we still cant really tell what is causing the sound. It looks like were gonna have a guy come over and take a look at it, but my dad thinks now that it might be a lifter.

What is the likelyhood that it is actualy a lifter? Or maybe we just missed something. Also, what are the chances that I may need a new motor. I talked to a couple people and one of them said they had a friend who ended up needing a new motor. My best friend ended up needing a new motor too on his 300ZX and it was making a very similar noise.

[TheGreenPunisher]

not having enough oil will cause the rockers to make a ticking noise...

[98Camaro3.8]

I've heard of a couple older 3.4s that had the rockers come loose. I'd get some new bolts (torque-to-yield so don't reuse them) and see if it helps.

[wasjo6431]

heres the thing u can tighten the lash without it runnig BUT YOU AHVE TO DO IT WITH IT RUNNING. the vavles that were loose were suposed to be they were closed. if it was open uw ouldnt be able to move it. u have to put the cover back on start the car idle around 300-500 rpm
pull the cover back off with it running set the lash. if uve never set the lash id ask someonw how its not easyt o explain it here. u hear the vlaves clacking when u losen them up. then u tighten it till uc ant hear it no more then go another 3/4 to 2/3 of a turn then tighten the lock and go to the next one. its not hard its just a PITA. i set mine loose to make more power its louder but i have a couple of bad lifters and a bad stud so i have a clack coming from the valve traint hats anoying
i reset my lash about once every two weeks. but soon ill be tearing the top end apart as in new intake and new lifters. cuz i have a couple of lifters starting to calapse u can hear them ticking. a lifter soudns different then a lose valve. rockers clack. lifters tick.
with the valves when u set teh lash u let them clack for about 20 sec. then start tightning. by doing this u are not only cleaning it out but u are making sure oil is getting trhough. MAKE SURE YOU HAVE UR VALVE COVER ON WHEN U START THE CAR dont let it idle to high do soemthing to kick the idle rpm down so u dont get squirted. 600 might be safe but its a lil to high to hear enough. btw u canf ind out which ones are loose by pushing on it if it stops the sound thats the loose one. u might have a few other loose ones but cuz you tightned them up without it running u need to redo it with it running.
sry to inform you about that. but its not gunna run right till its done right.

[viper98885]

You don't have to start the engine to get it to rotate. You can use the center crank pulley bolt and a socket on it to rotate the engine the necessary 180 degrees to get the valves that were not done while the number one piston was at TDC. Once you have finished the first set of valves, rotate the engine so that the number 4 piston is at TDC and do the remaining. I did a full write-up some time back about how to do this so if you do a search, I am sure it will come up.

[wasjo6431]

but to get it fully tuned propperly and set properly u want to do it with the engine running. this alows you to hear which valves are not done and which are. and u dont want to over tighten them.

[skriFF]

Ok, thanks everybody. The only thing I am wondering about how I'm supposed to start the engine with all this stuff (fuel rail/line, air plenum, throttle body, EGR, intake) off. Doesnt it technically need all of those things to run. I'm still kinda new to cthe innerworkins of the motor, so thats why I have my dad helping me with all of this. He tried to explain it to me last night, but he didn't do a very good job.

[wasjo6431]

u move them out of the way still haveing them connected u cant set valve lash without them moving to see what they do. if they are too lose or too tight. egr is useless. u need to find a way to get the covers off witht hat in the way there is a way. other wise gm is retarted for that. u can move stuff out of the way. the fuel rail in the center of the uper plenum. u dont need the elbow. when doing this u need the tb
injecters fuel rail. fuel line. uper and lower intake. once u get it to a nice low idle. u adjust the valve lash.
No matter what valves that are CLOSED ARE LOSE. if they are open u cant wiggle them.its the way its suposed to be if they wiggle when open then they are lose.

[skriFF]

Yea, the ones that wiggled did it when those valves were open. We did the whole turn the crank thing like Viper said. Thats how we turned the it and adjusted them. Spent like an hour and a half making sure they were adjusted correctly.

My dad says its not really worth it to put it all back together and then take it apart again so were just gonna have a family friend who is a mechanic come over and take a look at it.

[oil pan 4]

That's messed up that the lifters don't get enough oil because the cam and lifters in these engines have access to the most oil @ pressure compaired to every thing else in the engine.
Think what the rod bearings and crank jornals are going through.

[Tru2Chevy]

Please for the love of god don't set your valve lash with the engine running. Turn the engine over by hand and tighten the rockers on a particular cylinder right after the intake valve closes (this way both valves will be completely closed). General rule of thumb is to tighten just until the pushrod will not move up and down between the rocker and the lifter, then add another 1/4 turn.

I just went all through this with my buddy who did a cam swap on his 454SS pickup, and he set lash with the engine running anyway. He got one too tight as a result of it, snapped a pushrod, and is now paying $4,000 for a new cam (since that lobe was rounded off), shortblock, lifters, pushrods, and heads.

- Justin

[viper98885]

Originally posted by Tru2Chevy:
Please for the love of god don't set your valve lash with the engine running. Turn the engine over by hand and tighten the rockers on a particular cylinder right after the intake valve closes (this way both valves will be completely closed). General rule of thumb is to tighten just until the pushrod will not move up and down between the rocker and the lifter, then add another 1/4 turn.

I just went all through this with my buddy who did a cam swap on his 454SS pickup, and he set lash with the engine running anyway. He got one too tight as a result of it, snapped a pushrod, and is now paying $4,000 for a new cam (since that lobe was rounded off), shortblock, lifters, pushrods, and heads.

- Justin

Exactly. Do it with the engine off. You will have much better results.

[wasjo6431]

lol but when u start it if ones not tight enough go for it and turn it off and tear it down
the way most people do it is with it Running at alow rpm to allow you to hear. u cant over tighten if u can tune your ears in on One valve and one only. u tighten them up with it off. then u start it break them loose let the oil flow then after 20 sec of it clacking tighten till u cant hear it. depending on lifters go 1/4 turn to 3/4 turn after u hear the clack go away.
its how i set mine. then tighten the lock nut.
then shut if off make sure the lock nuts are all tightened.
or u can by an LS1 and u wont have to set it.

[98Camaro3.8]

Originally posted by wasjo6431:

or u can by an LS1 and u wont have to set it.

Or an L36. [img]tongue.gif[/img]

[Alt space n]

So whats the result on this job? What was the actual problem.