TOPIC: MARTIN 40

I finally got around to working on a 1950 Martin 40 that I picked up a long time ago. But one of the first thing I found was the spark plugs. All the catalogs I,ve checked say to use a J8C Champion plug but I found these to be too long and hit the casing. Doe,s anybody else have one of these and have they found a alternate plug? Thanks for any info.

They hit the casing? Do you mean the lower shroud? I think the original plugs would have had a spade clip type tip on them, rather than a rubber boot. Could be wrong. The spade tip would have a shallower profile and might not hit the cowling.

Also, check to make sure there isn't a helocoil thread repair in the spark plug hole - sometimes those will have a shoulder on them and can push the plug outwards a bit.

- Scott

You can see the diferance between the original plug and the replacement. With the boot off I maybe have 3/16" clearance it's actually the gas tank it hits.I was hoping for a shorter plug or maybe a different brand that will be shorter.

81ec, you Should be able to take the number off the old plug, or the plug itself down to any decent parts store and find a suitable replacement, I would think. (Try your local NAPA if the others can't help.) Just a suggestion.......

The one on the right is a J8. The other is a J8C the new replacement.