[Bob Bidonde]

If you are running a stock 4.2:1 compression cylinder head, and you change your modern motor oil regularly, the automatic spark advance accessory is a worthwhile accessory. I have found a few of the original automatic spark advance gizmos on engines over the years. Most were not working because the flywheel was stuck by sludge. However, I admire the engineering concept.

Many many Model A'ers run hi-compression cylinder heads that do not require the amount of spark advance the stock head does. So the automatic advance gizmo may be the cause of spark knock if running with a hi-compression head. Also, running the automatic spark advance with hi-test gasoline may cause spark knock.

My preference is to fine tune my engines to the running conditions each time I take the cars out for spin. I do this with the spark advance lever and the GAV. Both of my A's have hi-compression heads.