The Stovebolt Site Forums The Shop Area Engine Shop Leonard's Oil Firing Spark Plug (?)

OK...so I pick up this '56 3600 with what appears to be a Pontiac 347 V8 (thanks Luke). It runs but a little rough and is very cold blooded. I thought I'd start by checking the spark plugs. WT*?? They don't have a traditional electrode and are imprinted with "Leonards Oil Firing" on the insulator. What's up with that? Do they cross to a more modern plug?

The "fires in oil plugs" were used in worn oil burning engines that would foul normal plugs.Must be a reason for those plugs, huh? Perhaps the previous engine tuner installed those plugs because they were within arm's reach.At any rate just cross over to normal Pontiac 347 plugs, J-11 for Champion.

Champion!!!! those are for lawnmowers!!! :p

Thanks Tony. Let's hope they are in there because they were within arm's reach.

Well, according to NAPA, Autolite 86 is the plug for the 347. I was able to replace the right side before it started to snow tonight. When I pulled the "oil firing" plugs, they just looked sooty, not oily.

Autolites! Those are for FQrds

That was ages ago. Autolite/Motorcraft split and Autolite is now part of the Honneywell group with Prestone and Fram, the makers of junk oil filters. I can't recall the exact date, but I think the split was in the 70's. Autolite did make the best plugs on the market when they were owned by Fored, but not anymore. Myself, I've been buying AC/Delco and have had no problems.

I had a 74 pickup with the 250 that was a plug killer, they wouldn't burn up or foul, but the ceramic would break down and cross-fire internally. Champions would last 3,000 miles, AC about 5,000 but Autolites would go for 7,000 to 8,000 miles.

So Fred, who's oil filters do you like? I have used Frams for years and have heard good/bad about them. Some swear by them, and some swear at them.

Check here for some good info on oil filters. After reading this I'll not be using Fram anytime soon. I'm currently using AC/Delco with no problems.