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Oldgearz · 11-29-2020, 11:06 AM

Just got my first Model A and am enjoying working on it. I ordered new spark plugs (W-18) and set the gap at .035". This got me wondering about spark plug gap. I am very experienced (shade tree style) at working on my five Ford 8N tractors (1947-1951), and have changed many plugs in them They have the Ford 4 cylinder engine and their plug gap is .025-.028, quite smaller than the A's .035. For those of you who understand Ford 4 cylinder engines better than me, why would there be such a large difference in plug gap for the A. All the W-18s came with a gap of about .025. Why the difference in gap needs? The tractors are also 6V positive ground.

11-29-2020, 11:06 AM	#1
Oldgearz Senior Member Join Date: Aug 2020 Location: Sagle, Idaho Posts: 359	About spark plug gap Just got my first Model A and am enjoying working on it. I ordered new spark plugs (W-18) and set the gap at .035". This got me wondering about spark plug gap. I am very experienced (shade tree style) at working on my five Ford 8N tractors (1947-1951), and have changed many plugs in them They have the Ford 4 cylinder engine and their plug gap is .025-.028, quite smaller than the A's .035. For those of you who understand Ford 4 cylinder engines better than me, why would there be such a large difference in plug gap for the A. All the W-18s came with a gap of about .025. Why the difference in gap needs? The tractors are also 6V positive ground.