Pre-ignition damage..
For many years I have heard of many owners complain of engine damage like blown head gaskets and more, but state that they never recorded, or did see any knock?
Since pre-ignition will NOT set off the knock sensor, it can give one a false sense of security, but will cause massive damage, much more so than detonation.
This is especially true when using achy with pump gas and relative high boost. My response has been achy is NOT a substitute for race gas, even though some tuners have figured out how to deal with it. They understand it takes 3 time the amount of alcohol to develop the same HP as gasoline.
Pump gas in many areas of the country already is 15% alcohol, and has rapid deterioration of octane starting like 3 weeks after blending. So if it sits underground, or in your fuel tanks for a few weeks, it can be inadequate, especially for boosted application.
When we see spark plug damage like the side electrode gone, or the porcelain tip damaged or broken, or valves "tuliped", this indicates pre-ignition damage and VERY high heat was present in the combustion chamber.
As we build faster GN's and more powerful engines, we experienced some weird and massive damages which caused by pre-ignition due to inadequate octane.
Most we could find found early, but some customer's that did not heed our warnings, and ended up with VERY expensive damage like shown on the block below.
It had definite signs of pre-ignition, like the damage to plugs and valves, but the tuner decided to make another pass - expensive decision.
When the 2 rods failed, it took out the crank, cam, lifters, valves, torque converter, trans case and front pump, flexplate and misc. other parts, and obviously the block.
