Рет қаралды 12,057
This video teaches two methods for setting spark timing on the Ford Model A to arbitrary values, e.g., 19° before TDC or 5° after TDC. It also teaches some techniques for finding the top dead center point as accurately as possible without removing the cylinder head.
The first method involves calculating a length of arc around the crankshaft pulley and then offsetting the crankshaft from TDC by that amount. The second method involves calculating a length of arc around the distributor cam and then rotating the cam by that amount.
Update (thanks RK): If your car has the original pop-out ignition switch (and I mean a true original), when setting the timing using a multimeter as shown at 21:16, you must set the ignition switch to on. When in the off position, the original pop-out connects the point arm to ground, which makes the multimeter method not work. This means you need to work fast - don't leave the points closed with the key on for more than about 30 seconds.
I've heard two critiques of this video. First, "the vast majority of Model A owners don't need to know how to do this." That is correct, but it is a question that comes up frequently, so here is the tutorial.
Second, "this video is way too long, no one will watch this." I like to be comprehensive. Use the chapter headings below to skip to the part that interests you. I won't be offended.
Chapter headings
0:00 Titles and a silly animation I made to fill time
0:40 Review of Model A timing basics
3:07 Overview of two precision timing methods
7:36 Finding top dead center as accurately as possible
16:31 Step by step method to set timing by rotating the crankshaft
21:16 Finding the spot where the points open using a multimeter
25:40 Step by step method to set timing by rotating the distributor cam
41:45 Some caveats about how much precision is really feasible
43:25 Verifying your results with a timing light
44:57 Measuring ATDC timing indirectly
46:58 Closing thoughts