Posted by George in NW Michigan on Sunday, January 02, 2005 at 9:09AM :
In Reply to: Setting Timing With Vacuum Gauge posted by George (in Houston) on Sunday, January 02, 2005 at 8:01AM :
Setting timing with a vacuum gauge will get you close....but the method is not sensitive enough to get you spot on. I think you have discovered this. And I'd guess that if you tried this again, you'd end up close again but not necessarily where you have it now.
10 degrees too advanced does not sound good to me, especially on modern engines that were designed to run on good gas. The old cars from the 40s and 50s ran on very low octane gas which demanded that spark timing be very conservative (like TDC or even ATDC), so advancing them 10 degrees may be less dangerous....but even with these, 10 degree BTDC is probably too much.