Is the engine pretty safe as long as you have no knock?

[ryans1000]

Is the engine pretty safe as long as you have no knock? Lets say this is on 91 pump gas and you are within the physical horsepower limitations of the motor. If one is to play with afr's and timing will keeping knock at zero gaurantee safety?

I have a turbo ls1.

[joecar]

No, not necessarily... combustion chamber temperatures can elevate and knock won't necessarily occur (altho it probably will)...

elevated CC temp is destructive... able to melt holes in piston regardless of knock... altho knock provides the sharp blow after elevated CC temp has softened everything up... but elevated CC temp alone is able to cause damage).

Depends on what you're doing... in what range are you altering AFR and timing, and how is your motor currently running and what is it pulling...?

[eficalibrator]

Typically, two things kill engines: knock and RPM. However, you can still get some interesting failure modes with elevated temperatures like mentioned above. Don't ASSume that just because you see zero indicated knock on a factory knock sensor that you're safe. There's a significant amount of error possible in the way knock is detected/inferred/filtered within the PCM and a non-stock engine's noise floor is most likely not the same as the PCM's reference values.