How to adjust cobra rockers?

[SEB]

I just bolted mine in & ran them down tight & made sure I could spin my pushrod on each one & they work great!

[85turbocoupe]

Long story short i have a set of 93 cobra heads with the cranecam rockers. How do i adjust them because they are knocking?

Remove valve covers
Make sure whichever valve your adjusting is closed
Lifter on base circle of camshaft
Undo the rocker bolt and allow the lifter cup to return
While moving pushrod up and down stop at zero lash
Zero lash is achieved when the up and down slack is just taken up
From zero lash torque rocker to 20ftlb. Should be at 1/4-1 turn.
I aim for 1/2-3/4 turn
If it's more than 1 full turn pushrod is too short
If it's less than 1/4 turn pushrod is too long. Buy some shims
If pushrod is too short buy an adjustable pushrod to find length.
With pedestal mount a little longer pushrod is better than short

[red95gts]

Remove valve covers
Make sure whichever valve your adjusting is closed
Lifter on base circle of camshaft
Undo the rocker bolt and allow the lifter cup to return
While moving pushrod up and down stop at zero lash
Zero lash is achieved when the up and down slack is just taken up
From zero lash torque rocker to 20ftlb. Should be at 1/4-1 turn.
I aim for 1/2-3/4 turn
If it's more than 1 full turn pushrod is too short
If it's less than 1/4 turn pushrod is too long. Buy some shims
If pushrod is too short buy an adjustable pushrod to find length.
With pedestal mount a little longer pushrod is better than short

This

[89ghost]

is there a difference in lenght in the 93 cobra pushrods. i readjusted all the rockers and there fine. im at the point where i might have to take it to a shop and see WTF is wrong.

[89ghost]

Im thinkin it could be a bad lifter.

[FoxBodyNick]

Pushrod is the same length.

[red95gts]

You sure it isn't an exhaust leak where the header meets the head? Those can sound just like a tapping rocker.

[psdtech]

Sounds more like pinging to me. What fuel are you running? Either check your timing or use some 93 oct and see what happens.

[mikec]

shims

Lol. Grasshopper only learned half of the lesson I taught him...