1988 Camaro with a 305 tuned port. Start having a knock I guess?

I will record some of the noise soon. But its weird. I can hear it then all of a sudden its gone for a couple of minutes then slightly comes back then gone?? I have no idea

Others have told me piston slap but I thought that went away once the car is warm?

 

heres a video of the sound. Cant hear it real well but between the 12 second and 20 second area u can hear the knock.

 

no video.

 

LMAO.... Um yea here it is. I guess I didnt paste the video.


http://www.youtube.com/watch?v=SRc312gF0J0

 

It's hard to tell in the video. Take a stethoscope and old it up to the oil pan and valve covers to see if you can pinpoint where it's coming from. You can use a long screw driver and hold it up to your hear as well.

 

Jeez, that could be anything. The video doesn't help to pinpoint the source. Try removing your serpentine belt and run the engine again. Don't run too long though since the water pump won't be turning. If the noise goes away, it's one of the belt driven components, and you can start checking them one by one.

 

how many rpms is the engine idling at? it sounds like its really high up there. when my 305 developed a rod knock, it was a bit louder and slower than that, but was on one rod. pull your oil pan off and take a look to see what it is. if it comes and goes, it just might be an oiling issue. piston slap doesnt always go away once its warm, but it does get quiter. a stuck lifter also makes noise that comes and goes, but it isnt that loud and is more of a tap