Installed P30 pistons, strange sound now- is it normal?

Those who have either p30 or pr3 installed… I have now 400 miles after installation of p30 with new rings and new headgasket. My question: while accelerating, up to 3.5K rpm, the engine now sounds different, it is a little bit like lawn mower, chatters, somewhat audible, but definitely different than with the old pistons. It feels different for sure, just liek I said, like accelereting lawnmower tratatataaaatraaatatataa, drives me crazy just thinking maybe something went wrong. I feel the engine is a bit hesitant than before. it lost that zest. my engine originaly has only 60K miles, did i make mistake chaniging pistons on such relatively nice engine.

I noticed that fuel economy increase somewhat, but maybe because I am still breaking-in, not steping on the gas so fast.

and the last question, where should I set the timing now- 16 btdc or 18?

Any ideas why it behaves like this? or is it normal? my wife’s civic d16z6 pulls much smoother, it f§&%$ grabs, it is embarasing to me to loose to 1.6l.

Sounds like knock or detonation.

What octane petrol do you use? What heat range sparkplug? Which engine is this so we can get an idea of what compression you’re running.

Did you rebuild the engine or just swap pistons? Who did the timing belt?

Is it like a metal on metal sounding knock? It most definitely could be predetonation.

I would suggest setting your igntioning timing to 16, running a 6 or 7 heat range plug, and running the higest octane gas you have available.

I would also check your cam timing, could be off a tooth.