[eamonford]

Alright, so you guys really got me thinking... Eagle, you suggested to advance the spark until my engine starts to ping, then back off a little. Starts to ping? I’ve never heard my engine do that when advancing the timing, and I always drive at full spark advance because it feels way underpowered otherwise! So, when you said that, I thought maybe my distributor cam is too retarded, since I can’t advance it far enough to get engine pinging. (Big Hammer also mentioned earlier that 90rpm at idle sounds like spark is too late). So I advanced the cam by 15-20 degrees, and wow — now I’m getting 15-17mpg instead of 10mpg, and I barely have to press the gas pedal to get to 40mph. What a huge difference! I still don’t think I hear a ping when I run at full spark advance, but now at least it feels like I stop gaining extra power when I go to a click or two before full advance, which means I’m probably hitting the top of the timing curve. I think I can probably get a few extra mpg’s by finding the right GAV setting now that the timing’s more optimal, fixing the exhaust leak between the exhaust pipe and the manifold, and staying between 35-45mph.

I’m not sure why I had to advance the cam 20 degrees to be able to get the optimal timing... spark plug gap too wide maybe? In any case, I’m happy that it works and don’t want to look the gift horse in the mouth. Thanks everyone for all your help on this!