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CJD
Yoda
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Detonation could have many causes. The gist is that instead of the single ignition of the cylinder mixture by the spark plug, followed by a smooth burning across the chamber, there is a second ignition point. With 2 flame fronts, when they reach each other, the remainder of the mixture explodes simultaneously. It is equivalent to hitting the piston and chamber with a hammer.
Causes of the second flame front can be:
1) Ignition timing advanced too much, so the cylinder pressure becomes too high.
2) Poor fuel octane
3) Hot carbon in the cylinder
4) to high compression for the fuel octane
5) to hot of a plug rating
6) sharp metal edges heating in the cylinder
7) Cam timing
Normally the cast aluminum piston is the weakest part of the combustion chamber, and the ring lands are the weakest part of the piston...so they tend to go first. On more high performance pistons, with thinner crowns, the crown is the weakest point.
Causes of the second flame front can be:
1) Ignition timing advanced too much, so the cylinder pressure becomes too high.
2) Poor fuel octane
3) Hot carbon in the cylinder
4) to high compression for the fuel octane
5) to hot of a plug rating
6) sharp metal edges heating in the cylinder
7) Cam timing
Normally the cast aluminum piston is the weakest part of the combustion chamber, and the ring lands are the weakest part of the piston...so they tend to go first. On more high performance pistons, with thinner crowns, the crown is the weakest point.
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