What does spark knock sound like?
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
What does spark knock sound like?
My 86' makes a sound occasionally. It only happens under WOT in gear and only for about 3-500 RPM, as it winds out the noise goes away. It sounds like 2 heat shields shaped like egg cartons rubbing together real fast. My friend says it might be spark knock. What do you guys think?
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Knock (or detonation) is caused when the mixture ignites separately (on its own) at the same time as the ignition provided by the spark plug. The sound is probably best described as 'tinkling'. Caused usually by the mix being too lean.
Burning Brakes
Joined: Dec 2003
Posts: 1,183
Likes: 1
From: MidOhio
Sounds like spark knock. Did you ever hear an early smog car ('80s) "run on", i.e. keeps runnning after turning off the key? The sharp sounds you hear are spark knock (actually pre-ignition-same thing). The sounds are as sharp as a thumbnail size stone hitting your windshield. 
