I think I answered my own question.  If we had to advance the timing 5-7 degress to get to TDC, I still need to go to the 5 degree mark to get in spec.  So my engine must have actually been 10-12 degrees off.  I should have all kinds of new-found power now.

Clint Kolda <clint_kolda@yahoo.com> wrote:    With gas prices as high as they are, I thought it would be a good idea to check the timing on my van prior to the camping season.  My timing light is basic and does not have an advance feature.  As I understand it, the two marks on the pully indicate TDC and 5� BTDC.  I assume the V notch toward the front of the van is -5 and the U notch toward the rear of the van is TDC.  Initially my timing was in the range of -5 to -7 or so.

  at first I was a bit confused as to which notch was -5� and which was 0� and I timed it to fire at TDC by aligning the U notch with the case seam.  I went for a quick test drive and found the van to have noticeably more power and have better throttle response.

  I know the spec is 5� BTDC.  I did not hear pinging, although I understand it still can occur.  I only drove a mile or so and I don't want to leave it like this if it will adversely affect the engine or mileage.  What's the disadvantage to running he timing at TDC on 2.1?

  Thanks,
Clint