Re: 1936 spark plug threads.

Posted by Ross On 2024/7/11 5:49:21

1936 has the regular 14 mm spark plugs, no? Any auto parts store will have kits for repairing damaged spark plug holes; you only need to know the length of thread.

Spark plugs need to tightened to about 20lb-ft. Of course this keeps them from blowing out, but also important it makes possible heat transfer out of the plug into the cylinder head. This prevents misfire and also pinging caused by the plug being a hot spot.

Any locations in your head that will not "hold" will need to be helicoiled. Get that taken care of before doing any more troubleshooting. It may also be that your coil is breaking down. It is past its normal service life by a factor of nine.