1941 320 spark plugs

[Lawrence Helfand]

I am curious about what spark plugs are the best to install on My 41 Century. So many choices beginning with modern plugs vs nos vintage plugs. Would love to know what experienced owners are using and if there is a preference and why.Would modern plugs just work better due to advances in design and materials or would it matter with the low compression eight. Right now she is still running plugs from the 1950's.

[Buicknutty]

 I have used the new reproductions of the original type AC plugs in my '41 and it runs fine. Bought them from CARS a few years ago, and they are still fine. Of course us old guys will clean the plugs instead of throwing them away like we do in the modern cars. It will take many years of typical "old car" driving to wear out a set of plugs.

 Keith

[LAS VEGAS DAVE]

I like to find some NOS old plugs and run them but as far as the engine is concerned a set of modern plugs in the correct heat range will be just fine.

[FLYER15015]

 

Lawrence,

I just finished cleaning  my AC-46's that came with the car about 5 years ago.

I have a rather unconventional method of cleaning in that I never sand blast my plugs. I just wire brush the end an set them upside down in a 2x4 drilled for the insulator, fill them with carb cleaner, and light it, to burn off the carbon that has accumulated down inside. Then soak them in carb cleaner for 20 minutes, and check the gap and reinstall. Learned this from an old Jag mechanic in my youth.

 

These are the solid white insulator type, not the "green ringed" ribbed type.

 

You can find AC plugs in the 45/46/48/C-49 heat ranges on evilbay, but you need to be carefull about the length of the insulator if you are running the spark plug cover.

 

Mike in Colorado

[Chrysler300XMan]

Lawrence,

After removing the original plug wires and post-war plugs, my father and I installed Champion RJ12C plugs in our 1941 Century. This was in 2008. The 1989 Champion catalog recommended UJ12 plugs gapped at .025" for 1938-42 Buicks and UY6 plugs gapped at .028" for 1941 Buicks with 10mm heads.

 

Hope this helps,

 

Karl