SBC Mystery Knock
Hi guys. Can't seem to understand this one. I still have a random noise that sounds like large marbles bouncing around somewhere in the engine bay. It goes up and down with acceleration. The noise is not present 85% of the time, but when it does come around, it will do it cold or hot, and I can hear it from inside the car if I'm close to a wall like at a drive thru.
Car starts right up, oil pressure is good running and at idle, and throttle esponse is great. I swapped out the PCV, which I thought was the culprit, but the noise came back. Almost sounds like its coming from the valve covers, but I pulled the covers, adjusted the valves, and I don't hear it when I use my broom stick stethoscope.
I will say that the last time that I heard it at idle when hot, I 'thought' that I felt it choking the idle very slightly. I was thinking of changing the oil and adding some of the mystery oil to it.
Any thoughts? Thanks!
67 Black RS Coupe, 383, M21 & 10 Bolt Posi. Edelbrock E-Tech 170 Heads, 2204 Roller Cam, Air Gap Intake.
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