200ci knocking tap

[rt67stang]

Hey Guys,
I just put my rebuilt engine in my 67 mustang a couple months ago. Well it ran great up until about a couple days ago.I started it up and it had a knocking tapping sound. I don't know what it could be since the engine is rebuilt with no miles on it yet. Hope i dont have to take it back out of the car. Any suggestions are greatly appreciated.
Thanks ,Ronny

 

[bubba22349]

One thing to check would be the fuel pump.

 

[rt67stang]

it seems to be coming from under the valve cover i think, but im not quite sure. ill definatley start with the fuel pump though

 

[bubba22349]

If it's under the valve cover do you have adjustable rockers? If not did you check for the proper lifter preload you may need a little longer push rods

 

[Invectivus]

For what it's worth, I thought I had valve clatter, ended up being an exhaust leak. If you don't mind a mess, lift your valve cover a crack while running. Should get louder if it's valves.

 

[CobraSix]

Very easily could be a rocker is out of adjustment. Even on a rebuilt engine, they may need adjustments. I had to adjust mine after a few drives. And even randomly a few other times, I had one adjustment nut back out a little.

One way to differentiate between exhaust leak and valve tap is how it sounds with the engine under load. If the sound gets louder under load, but keeps the same frequency, it's usually an exhaust leak (or, you don't hear it very distinctly at idle). If the sound taps consistantly, same volume, at any engine RPM regardless of engine load, it's usually a valve out of adjustment.