Spark Plug Modification
Thread Starter
Racer
Joined: Jul 2000
Posts: 289
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From: Norfolk, CT
Spark Plug Modification
Every so often you'll see a racing tip in a car magazine that says you can pick up a few horsepower by trimming back the negative electrode on a spark plug so that the end is even with the center of the positive electrode. The rationale is this is supposed to unshroud the spark and allow better flame front propagation. Is this real or wishful thinking?
While we're on the subject of spark plugs - on the old, big diameter plugs that come with the loose sheetmetal gasket, which way should the gasket go - small diameter lip againts the block or the other way around? Does it make any difference? I've asked this of many experienced car guys and nobody seems to know for sure. I've been changing plugs for about 40 years and have always put the small diameter towards the block but never knew why. Just seemed to look right.
While we're on the subject of spark plugs - on the old, big diameter plugs that come with the loose sheetmetal gasket, which way should the gasket go - small diameter lip againts the block or the other way around? Does it make any difference? I've asked this of many experienced car guys and nobody seems to know for sure. I've been changing plugs for about 40 years and have always put the small diameter towards the block but never knew why. Just seemed to look right.
