Hello all. I am looking for someone who has had a similar noise occur. It is a kinda loose scraping rattle noise that happens at a specific rpm. At idle in park at around 1000 rpm. In drive only when it is near 1000 rpm. My camaro is an 89 IROC 305 TPI. I have gone around with a stethoscope and it is hard to pinpoint. I have let the engine run without the serpentine belt and the noise is still there. Smog pump, alternator and water have been replaced. None of the pullies seem loose. Car runs fine and healthy. Noise is just super irritating and embarrassing. I have seen at least one member on here that had the exact same issue. His was a Firebird 305 TBI. He posted a link to a you tube video and it was the exact noise I have. The fix was never posted in the thread and the member has not been on here in quite a long time. My IROC has been making this noise for a few years now. It does not get any better or worse over time. I have posted a link here to the noise I am talking about. Any help would be greatly appreciated. Thank you.

 

valve adjustment sounds like but I’m to drunk to watch the video can’t get it to load

 

check your water pump, your balancer looks ok but looks can be deceiving. Check your valves too it never hurts to adjust them if they come loose. Um dam that is a tough one because it’s different than if you see it in person. Dam I remember these old Camaros I’ve owned so many of them over the years. Great cars if they are taken care of. Good luck bro

 

take your belt off and then start your car for a minute and see if the noise goes away. Don’t run it like that for only just a couple minutes because you won’t have any water flowing inside. I bet it’s something real easy

 

then if it runs with the noise still there with the belt off you know it’s internal but if it don’t just give the other pullys a tickle and see if you can pin point it. Ok good luck

 

I have taken the belt off already and she still makes the noise. I have thought maybe the timing chain is a little slack. The noise does not speed up or slow down, just gets comes and goes and only at around 1000 rpm. Drives me crazy. I am military and she is my daily driver. Have not had enough down time to get inside any part of the engine. I am praying it is something more simple like you said. Thank you for the help.

 

It is hard to hear in the video, but since you have run it without a belt that should rule out your accessories. Check the back of the engine, the flywheel area to be specific. Maybe your flywheel is making contact on the starter gear or the bellhousing.

 

yea that is strange isn’t it

 

I’ll get back to you on this one because now it’s gonna bug me until you fix it. I would try the flywheel and things too it won’t hurt at all to have a peak. I’ll get back to you. I’m interested to see what the heck it is.

 

I wonder if it’s the dust cover between the transmission and the engine

 

it happened to me once. That very well might be what it is. The flywheel is rubbing the dust cover. When it happened to me I was able to reach on the bottom and pull it away from the flywheel I hope that’s what it is

 

but don’t reach in there with the engine running would be all bad

 

Yes. I agree. That would be bad. I will get under there after work tomorrow and see what I can see. Maybe a loose heat shield. Catalytic converter is has been removed. Exhaust is tight.

 

sounds good bro

 

If you're checking underneath, you might check the flexplate bolts and even get a visual on the flexplate for any obvious cracks. It seems as if you may have something with torsional excitation. Those forces and vibration amplitudes are highest at idle or just above idle

 

Hey man did you ever figure the noise out? I have a 92 firebird that makes the same noise yours does in the video you posted. It rattles right at 1k rpm or a notch down from 1k but in drive when the rpms drop its silent.