knocking noise and blowing back through the intake

[tistan2]

I was out running my car tonight and I got it too about 5000rpms in third gear when something let loose. It sounds like something is hitting the valve cover on the passengers side. I took off the upper intake but I was to tired to go any farther. When I turned the motor over the last cylinder on the passengers side was blowing back through the lower intake runner and making a popping sound. I have scorpion rocker arms on afr heads. Does it sound like maybe one of the rocker arms somehow loosened up on me. The way it is blowing back through the intake makes me think that the exhaust valve is not opening for some reason.

 

[TheUser]

kinda sounds like you answered your own question If a rocker did indeed come loose, then the valve wouldn't open, so it's gotta go somewhere. If you have a compression checker, it might be smart to check compression, at least on that cyclinder, to make sure you didn't blow a ring...I would think that would be a good possibilty if a rocker comes loose, especially at 5000 rpms. Ironically, this actually happened to me, but I had just reinstalled the rockers and didn't torque them yeah well they were all loose and the car ran like absolute crap...surpisingly, it didn't break anything.

 

[tistan2]

yeah well they were all loose and the car ran like absolute crap...surpisingly, it didn't break anything.

Well my car was not running like crap. I just bought a lightning about a month ago and it just turned 1k miles. I had not got on the lightning yet so I took both out to see which was faster. Me and my buddy ran for about a 1/4 mile. My mustang walked my lightning by about 2 carlengths before it went to knocking.