My engine has continued to make slight ticking/knocking sounds regardless of temperature. This is not the sequenced clacking created by injectors. The engine (382 LS1) has only 8K miles on it. The sound does increase frequency as engine speed is increased. It does NOT sound like a main bearing. Sounds like it is coming from the intake valley area or possible from somewhere below #1 or #3 pistons in the driver's side head. As RPMs are increased it *almost* seems to go away. Sometime I think I can still hear it though (hard to over the exhaust noise).

One engine builder said it might be a wrist pin failure. I thought that seemed a little strange for such a low milage engine (with no hard runs or track passes). I have never hit the rev limiter or missed a shift, either. My idea was maybe a bad lifter? The engine has a hard time idling sometimes (surging, etc) and overall seems a little "off-balance" as a lot of vibrations are transmitted into the shifter, firewall, gas pedal, and floorboard. Could this be caused be a bad lifter?

I need someone to help me here. These are the clues:

1) Engine runs a little rough. Seems to improve somewhat as engine speed is increased. Transmits more than normal vibration through entire interior.

2) Slight clack/knock from higher up in the engine at all operating temperatures.

3) Car has tendency to surge at idle alot and even at low RPMs in higher gears. Rear end loads and unloads a lot at constant cruising speeds transmitting hard drivetrain "hits" through entire car.

4) At constant thottle positions engine will sometimes bog down for a split second before picking itself back up.


PLEASE NOTE: The springs, retainers, spark plugs, plug wires, coil packs, injectors, PCM, and PCV system have ALL been replaced in an effort to fix this problem.

I really don't want to go tearing into the engine unless I have good cause. Please! Help me with this, guys. You're my only hope!

-Kris <img src="gr_sad.gif" border="0">
kjboughton@home.com

 

The rough idle, surging, and so forth are tuning issues. The ticking sound is probably a lifter starting to wear out. Try heavier oil and see if the noise goes away.

 

Any way that I can diagnose this further?

TTT

 

Man Kris, you are somewhat snakebit on this setup. What you describe could be a lifter. I've seen the roller on a lifter get jammed somehow and wouldn't turn, this caused it to wear out the cam lobe it was on and make a clacking sound. Hope that isn't the problem!

Any misfire codes or SES lights? That "out of balance" and vibration feel is something else, a lifter wouldn't do that from my experience.

Tony

 

Find which side it's coming from and pull the plug wires one at a time and if it stops clacking on one you may have a cracked piston or pin problem on that hole. If it never changes if may be something else.

 

Take off your oil fill cap with the car running. If it is puffing like a train you have a broken ringland/piston.
Perform a leakdown and compression test on all cylinders.
Who built this motor BTW? You have been having nothing but engine problems for the last 2 years.
Chris

 

[quote]Man Kris, you are somewhat snakebit on this setup.<hr></blockquote>

Exactly. I am cursed.

[quote]Any misfire codes or SES lights?<hr></blockquote>

No misfire codes. No SES light. Car thinks it's a racing champion as far as it's concerned. Could it be a loose wrist pin like a local engine builder suggested maybe allowing a piston to move too much in the bore? Let me know if you can think of anything else to check.

[quote]Who built this motor BTW? You have been having nothing but engine problems for the last 2 years.<hr></blockquote>

Ugh, don't remind me. You're right though. I do nothing but throw money at this engine and nothing ever seems to help. The engine was built (and rebuilt after a valvespring failure) by Pat Musi in his NJ shop. Just recently changed the springs and retainers (to CC918's) after another valvespring failure, that was a Crower spring.

I am just SO freaking frustrated. I don't race the car or beat on it. 99% of the time I drive like my grandmother and all this car does is perform and run like crap. I would probably sell it if I could but I know I would NEVER get close to my investment out of it and the fact that I would never wish this cruse of a car upon any other human being. I keep thinking that I am going to figure it out and finally get it run. The thought that the answer may be just around the corner helps me to hold on but that is wearing off. Thanks for your concern though. I appreciate it.

[quote]Find which side it's coming from and pull the plug wires one at a time and if it stops clacking on one you may have a cracked piston or pin problem on that hole.<hr></blockquote>

I'll do that. Thanks for the suggestion. I'll come back with some data as so as I get this done.

[quote]Take off your oil fill cap with the car running. If it is puffing like a train you have a broken ringland/piston.<hr></blockquote>

Nothing coming out of the oil fill cap. Everything looks good there. Thanks for the suggestion.

Still hoping to find the answer. I would really hate to have to drive this car off a cliff.

-Kris

 

Maybe you should have ARE build you a motor. You would run strong, have awesome service and their motors are built to the ****. They could also take your motor apart and figure out WTF is going on with it, do some more work on your heads. Or use your existing crank and have ARE make a budget Superstroker for you. you could get into a 427 for a decent price considering you already have the crank and the rods.
Good Luck,
Chris

 

I had a bad lifter, and my symptoms were pretty similar to yours. VERY noticable tapping sound (nobody could miss it) and the engine vibrated like crazy...shook the whole car. It would also surge a bit (it does this anyway, but it did it more when i had this problem). The tapping sound also increased frequency with RPM and seemed to almost go away at higher RPM but you could still barely hear it.

I replaced the lifters with another set of stockers because I had heard that the Comp R lifters were really loud. That fixed my problem...car doesn't shake like that, tapping gone, most of the surging gone (unless i've just started it up). I'm no guru, but your symptoms sound a heckuva lot like mine.

 

well...on the bright side...you have the 'expensive' part of a 422 motor <img src="gr_images/icons/wink.gif" border="0">

maybe look into having the rest of the conversion done and fix the little 'nusiance' while its apart... <img src="graemlins/gr_devil.gif" border="0" alt="[devil]" />

though, some valvetrain noise is normal on these LS1s...hell mine makes more noises than most LS1s around and continues runs its ***** off <img src="gr_grin.gif" border="0">

[ January 31, 2002: Message edited by: Fireball ]</p>