Which Mark is 15 BTDC?

[Hijacker]

Setting the timing on my car and I forgot which tick mark is 15 BTDC

[rudee023]

Uh, why did you do a write up on how to set your timing without knowing which mark it is for sure?

[Hijacker]

i took a guess (assuming each mark was in 5 degree increments starting at -5) and was right. I was downstairs fixing a timing issue when it dawned on me to write that write up.