Here's the details, i was driving hard today in 2nd at about 4000, but never over 4500 rpms, trying to burn off some carbon that was causing my engine to diesel (advice of an old friend, who happens to be a mechanic) after about five minutes i start hearing a rattle in my top end, i immediatly pull over, and when at idle, the noise is gone, but once i start to accelerate the noise increases proportionally to my rpms. Its definatly in my top end, i definatly have the right amount of oil in the car. It litterally sounds like there are marbles bouncing around in my top end. If i touch my intake i can literally feel something bouncing around. The current plan is to pull the oil pan in the morning, check for any bad signs down there. Im also considering pulling the carb and intake and seeing whats laying down there. If anyone has any idea what this could be or at least what i need to look for to fix this it'd be AMAZING. More details: I still have an even exhaust tone, it still drives and runs just like the day i got it (approximatly 30 days ago...), its just making this horrible scary noise. Please help. This car is my dream car. Its my baby, and most importantly, its my project... but i need it running.

 

One more thing, today i filled up with what very well may be bad gas, the last like 20 cents worth at a kroger gas station, and mid grade at a crappy gas station.

 

OK
Lets look at this.
When did the car start to diesel? Was it dieseling when you bought it?
I'll suppose it was because carbon builds up over time. If that is indeed the cause.
Could a piece of carbon have fallen off into the chamber?
How is the mixture set?
Have you researched dieseling before trying to cure the problem?
Bad gas is never good and I only use the same service station for all my vehicles.
There are just some places I would never fill up at. I only use the quality gas from reputable stations...i.e. not johnnie's gas station or similar self owned franchises. They will buy the cheapest they can get hold of to maximize profits.
It would be a good idea to pop off a valve cover and listen there to eliminate loose rockers etc as that noise would increase with RPM. If a bunch of carbon was released there may be excessive tightness or looseness in them.
I'm kind of shooting in the dark here but I would not drive my baby or any of my cars with a rattling noise from my motor.
I'd have to tear into it. But that's just me.

 

The car has dieseled since i got it, the dieseling increases as the car heats up, and is non existant when its cold. I have done my research on the dieseling, and its definatly being caused due to excessive carbon, but ironically now that the dieseling is stopped, Im definatly not driving it till i get it fixed. My mixture runs very lean, the only reason im thinking bad gas is the fact that i had to fill up at such a garbage gas station, due to my normal one being out of gas. When tearing into it, what should i look for? Im definatly looking for things out of the ordinary, but ive never had to tear one of these down due to problems, if its carbon, has anyone heard of just chunks of carbon bouncing around an engine? I guess im gonna start tearing down, and ill post pictures as i progress. Thanks for all the help.

 

Ok, driver side valve cover off, everythings ok. Unfortunatly i got rained out... but i cranked it again and listened real close, and its coming from the passanger side valve cover, i can actually feel something smacking around in there when i give it some gas. So, once the rain lets up, im going to pull it and hopefully find my problem... (hopefully its just a chunk of carbon and i can get it out and be good to go.)

 

I wish you luck on that...but unfortunately I don't see how carbon can get up there unless the valve stems are completely shot.
Check the lash while you're at it with the covers off...There are detailed instructions on here for you to follow. It's a good thing to eliminate whilst you have them covers off. It doesn't hurt to re-lash them anyways since it's probably been a long time since they were done at my best guess.
I hope you just find that it's something simple and not a serious problem.
Please if you can take some pictures of what you find it can help others in the future.

The best of luck to you.

 

Sounds like a rocker arm/stud/spring let go to me... But who knows. You just need to pull it open and look. As long as the lifter is okay it shouldnt be too hard or expensive to fix.

 

Well, every single day i get to work on the engine, i get rained on. I had both valve covers off today, and got rained out. So the car is still parked for now... One note though, is it just me, or is the passanger side valve cover a PAIN to get off? Everything under the valve covers checks out, but when i get a free day (probably 2 weeks away) im going to seriously tear into it (taking pictures of EVERYTHING). Ill keep ya'll posted with progress.