The Stovebolt Site Forums The Shop Area Engine Shop Low pressure 235 spark plug numbers.

I'm trying to chase down a problem with my '46 235. the engine lugs on acceleration. I've put in points-condinser, wires, plugs, set timing, and cleaned carb. I replaced the plugs and that was the only step that didn't lead to any improvement. In fact the new plugs probably made the truck run worse.
There were Autolite 4194's gapped to 0.020 in the truck so that's what I replaced them with. I gapped them to 0.040, per the manual. The truck has a pronounce backfire now, that is worse than before. I may go back and cut the gap down some and see if that helps.
Is there another plug, or a different gap that y'all recommend? I've seen an Auotlite 3136 mentioned upon searching the forums. In running these in a '46 two ton, but probably will never really load the old girl that much.
Thanks,
Scott

Forgot to mention these are the small 10mm size plugs.

Why the .040 gap on new plugs when replacing older ones with .020?

The service manual lists the gap as .040". That's where I got that number from.

Sounds like you have weak spark If it runs better with the smaller gap. Thats probably why someone set the gap so close on the old plugs. You may have a bad coil or the wrong coil. Is it still running 6 volts?

Yes, I'm still running 6v. I didn't replace the coil, as it is the original style where the wire for the distributor comes out the bottom. I may have to end up getting one of those, I don't suspect that is a FLAPS item. I also ordered some Autolite 3136 as NAPA shows those as correct for the application. We shall see what difference that makes.