What is this engine clattering noise

[tgferg67]

http://youtu.be/qPume8sOYxA
Clattering noise when rpms fall at a certain rpm range.

This is a 1997 Saturn SC1. This noise has been around for 60k-80k. I replaced the lifters, rocker arms and rails from a lower mileage engine and the noise persists. I'm thinking it's piston slap?

 

[440Magnum]

Definitely NOT piston slap. Piston slap is stronger under loading, so you hear it more loudly on INcreasing RPM or under load while driving. Clatter on falling RPM is usually either wrist pins or (if you're really unlucky) a connecting rod bearing on the way out. If its been around as long as you say, its wrist pins and they're pretty well "egged" by now, but they don't fail suddenly and violently. It'll just slowly get louder and louder. I guess if the rest of the car lasts long enough a piston will finally crack from the hammering.

 

[tgferg67]

The rod bearings were replaced and plasti-gaged 20k ago when the engine was re-ringed. The noise was there before the re-ring. The engine is quiet at idle without trying to make the sound.

 

[1 SX]

Really sounds like a wrist pin.. my ford taurs had a 3.8L, (You know where im going with this...) and well it would sound fine a idle, but inbetween shifts this noise would happen, and well it got so bad it blew in my driveway after a heavy throttle merge.. Total time was around 3000 miles.. But pretty sure i also had coolant in the oil... and it was synthetic to top it off..

This is what it sounded like.
http://www.youtube.com/watch?v=cCdV-fqFpVE&feature=related

 

[tgferg67]

Originally Posted By: SL2
Really sounds like a wrist pin.. my ford taurs had a 3.8L, (You know where im going with this...) and well it would sound fine a idle, but inbetween shifts this noise would happen, and well it got so bad it blew in my driveway after a heavy throttle merge.. Total time was around 3000 miles.. But pretty sure i also had coolant in the oil... and it was synthetic to top it off..

This is what it sounded like.
http://www.youtube.com/watch?v=cCdV-fqFpVE&feature=related


That noise is completely different in that it gets worse under load. Mine get worse with load and rpm's coasting down.

 

[tgferg67]

The noise is coming the top piston/valvetrain area.
I think it is piston slap due to the bores being out of spec at the top last 1/2".

This video shows what the noise probably is.
http://www.youtube.com/watch?v=hS3YVQBF4l4&feature=related

 

[Spykem4e]

could it be the timing chain that is now a little stretched or a bad tensioner?

 

[440Magnum]

Originally Posted By: tgferg67
The noise is coming the top piston/valvetrain area.
I think it is piston slap due to the bores being out of spec at the top last 1/2".

This video shows what the noise probably is.
http://www.youtube.com/watch?v=hS3YVQBF4l4&feature=related


It sounds NOTHING like piston slap. Piston slap makes a gasoline engine sound pretty much like a diesel, gets significantly quieter when hot, and gets louder on throttle UP, disappears completely on coast-down.

You have wrist-pin noise. It sounds like an aged Chrysler 2.2/2.5, which were notorious for wrist-pin noise. They were also notorious for running 100k miles after the wrist-pin noise started.