Valve Train Noise **UPDATED** Cause Found?

[firebird1324]

***UPDATE***

So I took off (moved out of the way) the intake manifold to inspect my lifters, and found a pile of carbon build up between cylinder 3 and 5 (where the noise sounded like it was coming from). Only one of the lifters look liked it was semi-collapsed, but perhaps a peice of carbon got stuck in the lifter's plunger? The only part that confuses me is how would hydro-locking an engine cause this pileup in one select spot...and then cause a clacking noise right after? Maybe it's a weird coincidence and the pile was there before? I dunno man, but I guess I'll clean things up, put it all back together and see what happens. Here's some pics, what do you guys think?








Here's the original story:

The 5.7 TBI on the wagon is clacking at me.

It's the typical water story. Rain's coming down hard, road drain off is overflowing, you hit the water just right and the intake sucks in a butt load of water. Engine stalls, doesn't turn over, you tow the car home with your grandpa's truck.

So I've gotten it back up and running, I took out the spark plugs, turned the engine over by hand, emptied the cylinders and changed the oil. Replaced the air filter, plugs and wires. Now she runs fine, but my right side (1,3,5,7) is clacking at me. I took off the cover and pulled and checked the pushrods, rocker arms and all valve installed heights are the same. Valve lash was a little excessive, but I tightened them all back down to specs when I put it back together.

It runs like it did before. No misses, just clacking. I'm starting to think it's a bad lifter...because a bent valve would cause driveability problems. I have oil pressure, and there's no check engine light on.

What do you guys think?

[firebird1324]

nothing? anyone?

a second opinion is always nice before I start tearing apart my engine...

[Triple-X08]

i would run some oil flush through it, see if it cleans the lifters. sounds like a lifter to me as well.

[big swede]

Originally Posted by firebird1324

nothing? anyone?

a second opinion is always nice before I start tearing apart my engine...

Well to me it sounds like you might have put it into a slight hydro-lock situation and bent a pushrod or a valve.

I think you're not getting many replies because you have done a good job of checking all of the obvious things.

[Smaart Aas Saabr]

Yeah the obvious has been checked

but then again Chevrolets always make valve noise

maybe lifter has collapsed, you'll only know if you look

[firebird1324]

Originally Posted by big swede

Well to me it sounds like you might have put it into a slight hydro-lock situation and bent a pushrod or a valve.

I think you're not getting many replies because you have done a good job of checking all of the obvious things.

well I was hoping it was simply a bent pushrod, but when I checked the side that was clacking at me, they were all straight and in good shape. I didn't take off the heads to check the valves, but I didn't think that was it as the engine runs fine with no misses...a symptom a bent valve would make. I'm hoping now that it's a collapsed lifter, and not something like a rod bearing or rod itself. You would think that something up top would bend before a rod though. Grah, i'm so flustered!

[firebird1324]

also, when I spun a rod bearing in the firebird (3.1L) the noise was much deeper and louder, and when revs increased, the noise would increase, hesitate, and then return to it's normal beat. with this noise, it stays the same pitch and increases with revs then returns to its original beat. based on what i've been looking at on youtube, it sounds like a lifter...i'm gonna take of the intake tommaro and check it out.

[Triple-X08]

i would clean out all that garbage and run oil flush through it, probably not a bent valve as you said. i agree you would have more problems than you do.