1996 Chevy Cavalier engine tapping

Tiny
MIKE T.
  • MEMBER
  • 1996 CHEVROLET CAVALIER
  • 4 CYL
  • FWD
  • MANUAL
  • 160,000 MILES
I inquired earlier about this problem with my 2.4L twin-overhead cam engine concerning hydraulic lifter testing. After testing all the lifters at a repair shop(which all came back good) I removed the coilpack and bridged it to the plugs w/ sparkplug wires. With the engine running, I removed each wire 1 at a time creating a "dead cylinder". No matter which wire I removed, the tapping remained. All lifters are good, I replaced the rod bearings(out of frustration n' I was in the mood) but I can't seem to narrow down the location of this noise. I'm out of solutions and don't want to do more damage to the engine in its current condition. Any suggestions would be greatly appreciated.(Wrist pin, maybe? Please no.)

Thanks,
Mike T.
Thursday, February 14th, 2008 AT 12:14 PM

3 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
That is an all aluminum engine, they act like speakers. Are you sure the noise is valvetrain? Could it possibly be coming from the timing chain area? The valves are still moving, the lifter will still be noisy if there is no spark to the cylinder
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Thursday, February 14th, 2008 AT 3:50 PM
Tiny
MIKE T.
  • MEMBER
  • 6 POSTS
Thanks for getting back quickly to my question. However, my 2.4L Z24 engine is not all-aluminum. The top end is (head, camshaft housings), but the block is cast iron. Dont know if this makes a difference or not. The tap goes away under load and when engine braking, but is prominent at idle and when cruising at speed. There is a hard miss sometimes when really get into it. Could I possibly have a weak valve spring?
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Thursday, February 14th, 2008 AT 5:40 PM
Tiny
2CARPRO JACK
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My bad on the block being iron. Could be a bad valve spring. Or maybe a valve hanging up in the giude
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Friday, February 15th, 2008 AT 7:03 AM

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