42 9 N plug gap

ELECTRONIC IGNITION What should the plug gap be??? And what plugs are recommended??

NGK3112 0.025 for gap

Same as NGK B6L

Maybe I know there is 2 numbers on them and one is the 3112 not sure of the other number/letters

That is incorrect! The NGK 3112 is a B-4L!

Whoops???!!! just a tad cooler, they cross to Autolite 437 best match on NGK cross reference

I guess the B4L are a bit hotter like Chumpions H10 vs H12

I've no problems with the B6L vs Autolite 437

This post was edited by Mad Farmer on 07/25/2021 at 04:35 pm.

Are B4L hotter than H10/437?

Plug gap does not change with EI. OEM FORD TRACTOR spec'd at= Champion 14 mm H-10, but since then the Champion H-12 was developed, a hotter plug, and the AUTO-LITE 437 Plug is a similar clone. BOTH work just fine on Ford Tractors. Plug Gap spec'd at = .025 -.028. I set to .027. The H-12 is also now listed as the Champion 512 and the AUTO-LITE is now listed as the 216. Why, who knows? FYI & FWIW: The plug size, 14MM is the thread size of the plug, actually 14mm x 1.25mm (1.25 is the pitch)which equates to .5512 x .0492, in decimal equivalent/inch size. The head is tapped to that size in the plug wells as well. You won't find an inch size equivalent so don't look and don't try to tap or chase with anything else. If you think you need a 'hotter' plug, perhaps you have another problem. FORD Front Mount Distributor (2nd most misunderstood system on a Ford) must be mounted one correct way. The male cam tangs on it are offset and must match the female cam slot on the engine. If it gets forced off 180 DEG, you will bust the aluminum base and render it junk. When that happens you will never get the unit to work right if at all. Many experience this problem and then out of frustration, think they need to switch out to 12V or, EI when that fails too. Once the base breaks, regardless if 6V, 12V, or EI, the unit will never function correctly again. You can salvage the plate with all the guts and replace with another base or swap out with another distributor known to be tested and good. Just get it mounted correctly. Finally, it doesnt matter which setup you use, 6V, 12V, or EI, all have their respective PROs and CONs, just be certain you know what you are doing and changing out for all the right reasons. If it aint working on 6V, what makes you think it will on 12V, or EI? Having the Correct Wiring is the most important issue on any machine.

FORD N-SERIES TRACTOR FRONT MOUNT DISTRIBUTOR NOTE OFFSET CAM TANGS:

FORD N-SERIES TRACTOR FRONT MOUNT DISTRIBUTOR WHEN MOUNTED OFF 180:

Tim Daley(MI)