Intermittent tapping at idle

Iowa rust

New Member
Jun 5, 2007
I just slapped an engine together for my 92 coupe.
The engine has rebuilt gt40p heads with comp valve springs, decked .005, b303 cam, exploder intake and a stock bottom end from a 89 mark vii. I reused the mark lifters wich have been setting around for about 3rys.

When i start the engine it taps on occasion from the passenger side and under the intake and valve cover. (not every revolution of the cam) If I rev the engine it goes away and it goes away when the engine is warm.

Could this be a lifter hanging up? Valves are adjusted correct. What do you guys think about running some atf or seafoam in the crank case/ and how much?
  • Sponsors (?)

i say run a whole can of seafoam through it. Gummy lifter. Are those lifters self adjusting? If not hows the tolerance on the valve lash? if it's jumping until the oil gets flowing up the rod on the rocker could cause the noise. just a thought