Hello EvoM

Have GSC zero tick lifters last 20k miles ago paired
With Kelford 272’s and did run good.

Went to the track and after a day, heard a valve tapping
noise between 2500-3500 RPM and after that rpm to redline, goes away.
Also, no tapping noise at idle and deceleration.

Did tried changing thicker oil from mobil1 10W40 to vr1 20W50
and the tapping noise went away.. sometimes there is a lil bit but you can’t barely
hear it.


I suspected a bad lifter/lifters? Or weak valve springs?

(Or oil pump? With 10w40 oil, 25 psi @idle and 70 psi @3-4k RPM
With 20w50 oil, 27psi @idle and 75-80 @ 3-4k RPM)

Cylinder head is stock at 136,000 miles, except for gsc zero tick and 272.

Any thoughts? Thanks

 

Maybe make your oil drain interval shorter.

 

Usually bad lifters make noise at idle.

You sure its lifter noise?

Try using rotella 5w40