Rocker/Lifter chatter

[macguyver]

What actually causes a roocker/lifter to chatter? I know it's getting oil but and is tightened to torque spec but it still chatters.
Any ideas?
Thanks,
Macguyver

[David Simon]

One of the lifters on my 88 was tapping and it ended up being a worn lobe on the cam and the bottom of the lifter was concave. The noise comes from the extra space left between all the pieces. Sometimes lifters will tap if the oil is old and thin or when you first start the engine and they're not pumped up yet. Good luck.

[Crazy_Jeepman]

several things cause this problem. as mentioned a cam wearing out this being a common amc problem. lifters can become gummed up dirty and they will stick in the collapsed state, not allowing them to pump up. this will allow excessive space between the cam, pushrod and rockers. this will also cause all valve train components to wear faster becoming noisier and noisier. the rockers are not adjustable ;)

[Lugnut]

Yep. Mine camshaft was worn out too. With the valve cover off use a tool (heck, can't remember what they call that thingy) to measure the lift on each lobe by seeing how far the rocker arm comes up from it's most downward position. If it's not coming up as far as specs. call for then plan on puttin' a new bumpstick in 'er.

[desert_freak]

My I6 clacks something fierce! I'm not going to even pull the head until I have the money to do the cam/tappets and possibly some head work (seals at least), because you don't want to tear into it only to find there is more damage than you hoped for and you don't have the $$$ to fix it right! My problem is once I get into something I have a hard time stopping, once you have a new cam, lifter, lapped valves, new seals, why not hone, rering, polish journals, new bearings.......

P.J.