Valve clatter at higher RPMs?

[SMEGMA STENCH]

I'm having some valve clatter (or some kind of noise that sounds similar) at RPMs above 3800. Anytime I get about that high, there is some kind of noise that sounds like valve clatter coming from the engine. What could it be? If it is valve clatter, why are they clattering? 94 GT 5.0

[racrguy]

Does it sound like rocks in a tin bucket?

[Denny]

Sounds like it pinging to me.

[racrguy]

Sounds like it pinging to me.

That's what I think it is too, but different knocks can mean different things.

[SMEGMA STENCH]

Well, it doesn't have the sort of higher pitched tones of rocks in a tin bucket. It just sounds like... well, valve clatter. I do have my timing set to 13 after top dead center though. Instead of the stock 10 degrees. Guess I can back it off and see what happens.

[Txstang1]

sounds like detonation to me. could be a shitty tank of gas ?

[SMEGMA STENCH]

Yes. Well. I've learned my lesson. Don't run 87 in a car that you have the timing advanced by 3 degrees. Doesn't make the noise with 93 in the tank.

[shumpertdavid]

Yes. Well. I've learned my lesson. Don't run 87 in a car that you have the timing advanced by 3 degrees. Doesn't make the noise with 93 in the tank.

Ding ding can't run extra timing on low grade fuel