Just a couple days ago my trans am started making a quite noticable ticking/knocking sound. The car still ran fine and pulls hard but this sound is driving me crazy. I have never heard an exhaust leak sound like that before so i seriously dought that is it. It ticks faster with rpm.

It only makes the sound when the engine is completely warm (has to be almost to 210 before it makes the sound). On a coldstart there is no noise to be heard or it is just quiet enough that it is drowned out, i cant hear anything anyways.

When the noise can be heard it is heard best in the fenderwell or underneath by the oil pan and bell housing. it sounds like it is coming somewhere from mid-engine. It also sounds most like it is coming from the drivers side. but hard to tell.

I had to pull the oil pan anyways for something else and while i was down there i looked at all the rod ends and did not notice any discoloration from bearing heat or anything else out of the ordinary. Also no ecessive shavings or anything like that in bottom of pan. I did not unbolt the rod end caps yet to inspect the bearings but it does not look like that is the culprit.

I also have not yet had a chance to pull the valve covers and check anything out. It is just very puzzling to me that it does not make a sound untill the engine is warmed up.

I could post up picks of internals to see if anyone else could see anything wrong with rods or bearings.
I just dont want to throw the pan on and bolt everything back up untill i make sure it is not coming from the bottom end because its such a pita to get off in the first place.

Has anyone else out there had this same problem ???
have any ideas? let me know, thanks

 

Sound like a rod bearing to me. Maybe (but doubtful) a wristpin.

 

Well, I think I've been where you are. Last summer one afternoon I had the wife take the SS to go get our carryout dinner. She didn't make it 2 miles and called back home to say the car runs bad and I need to come there. I just drove it earlier in the day and it was fine. So I get there and it's running very bad, missing and a random tapping sound. She doesn't know what happenend. I think she revved the engine at one of my buddies when she went past his house but still, didn't hit the limiter. So I limp it back home and have a friend come help me look at it since it will barely stay running. We took out the plugs. Found the #7 and #8 plug electrodes bent, no gap. Put the gap back to .035 and she fired right up and ran great....til it got warm. Then the knocking/tapping sound came. Did a compression test, all good. Drained the oil and didn't see much, thought maybe we saw some metal flake but not really. It would be fine when cold, but as soon as it got warm again it came back. With nothing else to go on we just started taking it apart piece by piece. After pulling the engine we still hadn't found anything. I figure a new shortblock is in order anyway so I took it to Lingenfelter as they are close to here. The took the shortblock apart and never found anything. Bearings, pistons, rods, all looked good. To this day I have no idea what the noise was exactly or where it was coming from. And we checked everything, heads, valvetrain, lifters. All misc. bolts everywhere. Nothing.

I hope you have better luck than I did lol. My new LPE engine is running great.. Sorry for the long story and I can't be of much help. It still baffles me what it could have been. Keep this thread updated, I'd like to hear if you find something.

 

Could be a lifter. It will be quite at startup when the oil is thicker, but when it warms up and the oil gets thinner it will make noise. My car will do this sometimes, only when hot and only when I have the rpms low enough for long enough. I can get rid of it by revving up enough to boost oil pressure above 60 for a moment.

If the lifter won't pump up at all it can take out your cam pretty quick. What is your oil pressure and does it fluctuate when hot?

 

The sound you hear could be a number of things. If the car feels like it lost some power it could be rod bearings. I would check the rocker arms to see if one or more are loose, then you should check the lifters. Pull the plugs to make sure there is no damage to them.

 

If its an automatic, you could have a cracked flywheel or loose flywheel bolts. From the area that you describe it could very well be that. Check the simple stuff first.

 

Thanks guys, it is a m6 and just had the transmission rebuilt along with a new clutch, flywheel, and pressure plate so i am going to pretty safely say it has nothing to do with fw or trans.

Juiced, im sorry you never found your problem i hope i can track this down, there is no way i have the money for a new short block. You got my hopes up at first untill you said you never found the culprit lol.

Thorny, my oil pressure is pretty constant at 40 at idle so dont think the pump is bad, but was thinking along the same lines you are that the thick cold oil pumps the lifter more and allows it to work, eliminating the noise. Hopefully its something stupid and simple.

Well im about to go pull the valve covers and investigate things, whats the best way to check the lifters just push down the pr and find a soft one? Before i get that far i guess i will check my spark plugs just to be carefull, you never know.
Also would it hurt anything to run each cylinder one by one without the pushrod in place and undo the injector? that would stop the noise if it was a lifter.. or a pr or rocker, right

thanks!

 

I've been told if the oil pump o-ring is pinched it will make noise similar to a lifter (then again I have no idea if the noise I'm hearing is a lifter...). My car exhibits similar symptoms to yours. I can't tell what "normal" noise is for a cammed LSx so I keep thinking something is awry. Although it's been like this for a year and 5k miles and the oil pressure never wavers so I'm tempted to just turn up the radio and say F it. Subscribing... I'm interested to see what you find.

-J

 

sometimes i have the same sound....cammed here as well. im beginning to think im just not used to a high lift cam. it never sounds loud or damaging, so i will wait to see what you find out.

 

A cammed car will always have a slightly louder lifter sound then a stocker, but the sound is constant and does not get louder as the engine warms up

 

If it was a ROD or ROD BEARING the noise would be loud all the time , does not matter if the engine is warm or cold. I say check your OIL LEVEL, Check to see if you have a loose rocker or damaged lifter spring 1st. Also check for a exhaust leak.

If you have a Manual Trans, engage the clutch while the car is running. If the noise goes away slightly it could mean you have a bad Trans INPUT SHAFT bearing or a bad THROW OUT bearing. You will hear this type of noise only once the motor is warmed up

 

I wish I could help more. Keep checking everything one by one. We took the complete valvetrain off of my car piece by piece, no broken springs, no bent pushrods, valves were all good. My oil pressure was just fine too. The car ran and drove fine again after we fixed the bad plugs but that knocking sound just wouldn't go away when it warmed up. It's not the normal piston slap or lifter tap either. I've had several 3.1L engines with the lifter that would tap pretty good and this sound is not that. And all of the LS engines I've had made the piston slap sound, no big deal. This was different. I know exactly what you are talking about. Sounds very much like it is coming from the pan and can be heard good in the fender wells. When it's running you can just crack the throttle with your hand and it will knock pretty good and faster. Does this sound the same?

Keep in mind my car was stock with lid, headers, and exhaust. And 29,000 miles. I was not happy about it at all!

 

I've had the same exact problem.

I changed the whole top end. I bought a bran new cam, new lifters, new pushrods, new springs, got different heads and still made the same noise. IT was quite at start up but came out when it was warm. Finally the noise got worse and this is what is now.

http://www.youtube.com/watch?v=V6F8OXQKTaU

Notice where the oil pressure is at!!

And here is the video before I put the cam in the car, when the motor was bone stock except for the hardened pushrods.

http://www.youtube.com/watch?v=sMzFFz0eboo

Oil pressure was fine, and would only come out when warm.

 

Yours sounds like mine first did when the wife called and said something was wrong. (if you read above lol) Very random tapping metal sound, not with the engine just random. But it was also missing like crazy too at that point. When we found and fixed the #7, #8 plugs it sounded more like the second vid. But it was harder for me to tell in that one. It sound very much like a rod bearing at that point but like I said, took it all down and found nothing.

Keep us posted blueTA, I want to hear if you figure it out.

 

Could it be a exhaust leak. A exhaust leak can sound like a ticking sound and they will usually get louder as the car warms up and the metal expands.

 

An exhaust leak at the flanges makes crazy noises. If you have headers, there is a chance that the bolts backed out and are leaking.

 

first vid sounds ******* scary.

 

well checked out the drivers side valvetrain and the pr's were straight and rockers were tight and the springs were good, and pushed down on the push rods and none of the lifters felt soft, also checked the sparkplugs and wires, all tight and gapped good, havnt had time to get everything buttoned back up yet due to work but once i do i think im going to take it to a few eperienced ears i know and get their opinion and then probly check the pass. side valvetrain and check the exhaust to make sure that isnt it, by the way i still have the stock manifolds on it,

and to tilly, that first vid sounds nasty, the squeak in there kinda makes it sound more like a spun bearing or a shot pulley

gonna go try and get it back together and see what else i can find, will keep you all informed, but man do i have a real bad urge to go out and drive it!

 

oh, and juiced, yes that does sound very similar to mine, if you rev it a little it almost makes more of a knock than a tick but at idle its more of a tick, and if i rev it a little while driving then let it coast in gear i cant hear it sometimes, like the sudden oil pressure build up makes it go away for a second, and jjd49 i dont think think its tranny/clutch related because it does it doesnt change the sound any with clutch movement or gear engagement, which i wish it did so i could just take it back to the tranny shop that did my rebuild and tell them to fix it lol

 

The second video is the precursor to the first video.

I have the motor out of the car, I just need to throw it on the stand and rip apart.