Sounds like something is rolling around in my engine!
 

The noise is getting worse. At first I thought it was the valve covers. Then the exhaust, well it is neither. I got under the car and had my wife start the car and holy @#$$. It sounded like there was a rock rolling around in the engine. It kept making the same sound over and over except when the engine was revved up. Then the sound was worse. Help what could it be. :bigears I will appreciate any and all pieces of advice.

Rocks
 

Is the engine running smooth? Does the rocks increase in speed in conjunction with the RPM?

Is your car an auto or stick?

Big Cat crumbleing into pieces.

Damage to inspection cover for the tranny

How is the oil pressure?

Need more info.

Good Luck

Corvette Mike

Use a big long screwdriver against your ear to isolate the noise, alot of external metallic noises sound like internal engine problems. My belt tensioner makes squeaking noises on occasion and I found it with this method. Good luck.

Mine just did the same thing. Pre-cat was coming apart inside. Gutted all 3 cats, runs like a champ.

Even if the cats seem to be strong and not loose. How do you know if it's the Precats and Cats? :willy: That would be a Godsend if it was. It's an 87 automatic. Yes the sound does increase in conjunction with RPMs. Oil pressure is fine.

Crawl back underneath without the car running and tap on the cats (not to hard, if they're not broken you don't want to break them) and if broken and making as much noise when running as you say they should rattle.

Crawled back under the car and taped the Cats, I heard rattles. Now what? Do I take them off and start the car and see if the noise stops? Then Do I buy cats and precats? Do I have to buy new precats or can I buy another set up that doesn't have the precats. Like some sort of a Y Pipe. Does Corsa make something like this, since I eventually want to get a complete Corsa exhaust?

Thanks all for your help. It is greatly appreciated. Keep the ideas coming.

I doubt runnig with out the y-pipe (open manifolds) you'll be able to hear much of anything. If you hear the converters rattling it sounds like you've found the problem.
As far as fixing it you choices are limited only by your funds and abilities. The easiset fix would be replacing the front y-pipe with a non-cat y-pipe and installing a new high flow 3-way main cat.

For exxambple something like this
http://www.mamotorworks.com/corvette-3-36-971.html

You could also just drop the y-pipe and attempt to remove all material from inside both precats, but also make sure you replace or atleast check your main cat for crap built up in it.

Some of your options depend on where you live and the emission laws. You should fill out your profile so we'd know these things.

No emissions laws in Northwest Colorado. The option you showed me was the Y pipe with no cats. Are there performance gains with this and does it make the car any louder? Looks like a nice easy set up.

I'd say with a nice flowing main converter and that y-pipe you should notice a minor performance gain (more so if there is broken pieces of the pre-cat in front of and blocking the main cat, which is very possible). As far as louder I would imagine hi-flow cat plus no pre-cats should make some difference louder/more aggressive tone this change will also be dependent on what the rest of your exhaust is (stock or aftermarket cat-back).

Drop the front Y pipe and using a long stout rod, hammer and breakup the pre-cats. The debris will drop out. You should be able to see the front end of the main cat with a good flashlight. If loose pieces of precat debris can be seen in the main, drop it off and shake out the loose pieces. No need to gut the main unless its damaged. Then I'd suggest that you purchase a Magnaflo cat.

Reassemble the exhaust and drive happily ever after........

I will be under the car tonight. Thanks again to the forum, you guys rock. :cool: Oh yeah if this isn't the problem I'll be reposting. It is hard to believe that debris in the cats can make that much noise. Holy Cow.

Before ytou run it too much why not pull the oil filter cut it apart and drain the oil to make sure it is not inside the engine as this 20 dollar check might prevent further damage in the engine should it be a spun bearing???? If the bearing comes apart and plugs the oil feed hole the oil pressure will not go down ..yet.. it could be anything from that to a bad piston pin boss cracked skirt.. There are a lot of reasons to get loud engine noises.. Be like a doctor first do no harm in the testing..
Dave

His converters are bad.

GUT EM ALL!

no cats = POWER

Check the heat shields on all the converters. If the heat shields are loose, then it will make a hell of a racket too.

What do you mean by converters? Is that the same as the Cats? I just don't know all the lingo. I'm still learning, thanks for your help.

Proper name is "catalytic converter" sometimes shortened and referred to as cat, cats, cat converter, cat converters, converter, or converters.
I know the torque converter is also commonly referred to as the converter as well, so sorry for the confusion.

In short you still need to replace or remove your converters.

Thanks BRO. I did go ahead and drain my oil just to check and see if anything was in there and there wasn't. Just a nice stream of oil coming out the oil pan. I have to get a size 15mm long socket to remove the y pipes. That's what I'll be doing tomorrow.