Date: Sat, 20 Mar 1999 10:28:04 -0500 From: Patrick Valleau <valleau8nopsamigy.net> Subject: Re: Explanation of engine 'ping' and 'knock'
Ping is also called pre ignition. It is caused by a combination of Ign timing, octane rating and engine temp. If the spark occurs at a time that is too early for the fuel at the engine temp, the fuel will burn too quickly as the piston is still going up and you will end up with an explosion instead of the fuel burning smoothly. Slight ping is not a serious problem but still not good and an effort should be made to get rid of it. Any ping in a turbo is serious! Knocking is also called detonation. This is uncontrolled combustion caused by excess temps in the combustion chamber. The fuel is being ignited by something other than the spark. This could be an incandescent plug electrode or sharp edge, or anything else hot enough to light off the fuel. This usually happens when the engine is way hot and will destroy the pistons very quickly. When this happens the piston is trying to compress an explosion. Not good! Pat
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