fixx
 

ok i got a good night of sleep on this one,,what made the pushrod bend?? this is what i think is happening..the pushrod got bent obviously from the piston hitting the valve,,the stem on the valve could now be slightly bent and is sticking causing valve trane noise..most likely the rocker slamming into the pushrod..do a cylinder leak down test to see if you have any bent valves...i would start with the cylinder in ?

does not sound internal to me...not rymic enough...exhaust flapper of something in exhaust ?

my 496 is being rebuilt, corner of piston was floating around in cylinder. The compression test told the truth. It was #6.Caused a very odd sound.

That's why I was guessing exhaust valve not opening all the way, the backfire will not happen every rotation, not rythmic at all. The bent push rod says it all IMO.

I'm thinking like You. Artie

My exhaust flaps bang like that. Not steady, nor consistant. It sucks!
But odd that #6 removes the sound!
I would run it again in the dark, easiest to see arcing!

Also think what bent the rod to begin with?
Maybe the replaced rod is bent AGAIN?
Sounds like a piece of something floating around?

Hydraulic lifters?? Stuck? That would bend a rod, thus bend it again too.

On another note, looks like your running it in an enclosed garage? Overhead door was shut :(
Water running?? just my observation from the video

I would pull the valve cover an feel the rockers when spinning the motor. I really think its a valve. slapping a lifter back to the cam. You should be able to feel it if I'm right.

make sure your wearing your lifeline and the lanyards are attached!

Why would the noise disappear with the #6 wire removed if the rocker/valves/piston where contacting other parts or a broken spring? I'd think that those conditions would be there all the time regardless if #6 was powered or not???
The uneven noise is odd, in both sound and irregular clicking

I agree sounds like exhaust flappers. But the bent pushrod and the fact it goes away with #6 plug wire removed is odd.