The Ford Barn - Spark plug

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3x plugs with high compression head

Should work fine, no problem.

Best gap for 3x plugs in model a with high compression head

That would be good info for me to have too. I'm about to install a set of 3X plugs in my fresh rebuild with Brumfield 5.9 head.

Quote:

Originally Posted by [email protected] (Post 2321671)

Best gap for 3x plugs in model a with high compression head

35 what i do mine no problems.

0.035 inch gap. With higher compression it will take more voltage to jump the gap, but an ignition system in good condition should have no problem with this gap even with the normal high compression head. An engine with a plugs with smaller gaps will not idle as well.

Run the plugs at your normal cruising speed and operating temperature for half an hour. Park without running the engine too much at a slower speed. Then take the plugs out to read them. The electrodes should be tan with no carbon or signs of burning. If the plugs show any sign of burning, try a plug with a slightly colder heat range. Read the plugs again after several hundred miles.

If you are getting carbon on the electrodes then your engine could be burning oil. If this is a real problem for you then try a plug with a slightly higher heat range.