super chevy

Just put a new 383 stroker in my buddy's ride. All new, trick flow heads, comp cams rockers, edelbrock rpm intake, etc.
Here's what's happening: Broke the motor in for 500 miles, at 600 miles, started to hear a mild tapping when cold, that fades away when warms up. Have isolated the tap at the #3 cylinder. You can really hear it with a metal rod pressed against the intake runner for #3. Have run the vavles repeatedly. It is not a loose rocker. It is not getting any worse eitherafter being driven another 100 miles. With a cut pair of valve covers (for adjusting lifters) you can put a metal rod right on the head above the valve, and can't hear the tap, yet when you put the rod farther up near the pushrod, you can hear it. Bent pushrod? Bad lifter? Any thoughts/advice appreciated.
SC

Pat Hall

iTrader: (31)

Hmmmmm, if you've tried adjusting the valves repeatedly and that doesn't help, maybe you do have a bad apple for a lifter, or a bad pushrod. Another possiblity is you might not be getting decent oil pressure up to the lifters when it's cold. A leaking or improperly installed plug in the cam galleys could cause this. The only other tapping noise I can think of that goes away when the engine warms up would be a bad wrist pin on one of the pistons, but that's pretty doubtful with a brand new engine.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."