ok heres the deal....car has ran fine for one year----now its ticking from the #8 cylinder.....i took off the valve cover and its a little louder. so i think maybe its out of adustment.and i tighten it up (the intake valve only) and then is goes away but in a few seconds it comes right back??... so i pulled the intake and bought a new lifter and put it in last night!! also switched the pushrods with another cylinder, and all back together and it does the same thing???.... could it be the springs weak??.........HELP!!!..................145000 miles

 

Been there, done that. You're valve guide is totally worn out on that valve. Don't ask me why only one, but those are CLASSIC shot valve guide symptoms. I had an exhaust on #3 go out on me in the exact same way a few years ago- all other guides were just fine.

To be absolutely sure you can take off that valve spring with the engine still in the car (post if you need help on how to do this), hold the valve off it's seat about 1/4" and try to wiggle the valve stem back and forth. The play in the guide should be HUGE and VERY OBVIOUS if it's far enough gone to cause tapping that bad.

 

Also, if the valve spring is broken you'll see it when you take it off- it can cause similar symptoms to a shot guide. I doubt this is the problem, however.

Also, try swapping a rocker from another cylinder and see if the noise follows the offending rocker (again, this is doubtful in this case, but possible).

 

thanks!!.... dont have time do do it yet..as im still working on another car...... but will it do any major damage if i run it for some time??... no racing!! its in an s10!!

 

No, not really. If the guide's shot it's done about as much damage as it's going to do, at least for a while. I drove my car for several months before I had a chance to fix it (pull the head, have new guides installed).

 

i did swap both lifters and pusrods with another cylinder and the sound is still coming from#8 intake...i can tighten it some and then it goes away for a few seconds, then comes right back.......it does get a little puff of some when first started

 

whhoooo problem solved!! but i feel so stupid....maybe this might help someone else............new pushrod and lifter--still make that ticking sound!! so i took the header bolts out and put some air in to remove the spring and checked the valve guides-no wobble at all nothing????...now im stumped!! UNTIL i notice the header gasket for the #8 is blown out a 2 inch piece......punt new gasket on and hip hip hooray! noise is gone!!.. but i feel a little sick!!....thanks for the help