List Wisdom needed knocking sound
 

I went for a drive got home and parked the car. Later on I started it and heard a BAD knocking noise like a rod bearing. I put it away and had my brother in law listen with a stethoscope when i started it. he said it sounded like the knocking wasn't comeing from the case but higher up and on the drivers side.
After about 3 weeks I was able to get the car towed to the shop and guess what. No knock. he test drove it a couple of times and I rode with him on a test drive and the car ran exactly like it always did!
the only thing my mechanic could think of was that maybe some thing like a small nut got sucked into the cylinder and disintigrated. the car runs like a top now. I can't figure it out.
I had a car with a bad bearing and this noise is just like what I remember. the shop is going to change the oil and checkfor metal in the case and filter. but thats all we could think of to check. Anyone have any ideas? TIA

Not sure what it would be, but I doubt it would have been a nut. That would have done more damage and most likely bent a valve or something (ask me how I know!).

I can't believe that myself. Maybe the car healed lol. When they check the oil I'll know a little more.

Reminds me of years ago on a Buick, I had a "knock". Took it to the dealer, and they found hardly any oil in the crankcase! (I think either the drain plug was not sealing, or I needed a new oil pan gasket.)

Carbon piece. Even the littlest piece of carbon that breaks off sounds like a detonated motor until it burns/breaks apart and is expelled. Ask anyone who owned an old Cadillac with those huge motors and they'll know what I'm talking about here. Sounds absolutely fugly.

I'll bet thats what it was. especially since the carbs need to be cleaned and rebuilt.

If you're worried, have your wrench do a compression test and leak down. That'll give you some idea of what's going on...and maybe some peace of mind.