Measurements of my Chotia 460 engine,
with a dial indicator in the bottom
sparkplug hole and zeroed on TDC.
This chart shows the degrees of 
crankshaft turn for the given amount
of piston travel.

Thousandths          degrees 
of an inch           before top
                     dead center 
                     (BTDC)


000			00
010			06
020			11
040			12
050			13.5
060			14
070			15.5
080			16.5
090			17.75
100			18.9
110			19.9
120			20.5
130			21.9
140			22.2
150			23.5
160			24.5
170			25.1
180			26
190			26.5
200			27
210			28
220			28.5
230			29.3
240			29.9 
250			30.5
260			31
270			31.4
280			32
290			32.5
300			33
310			33.6
320			34.1
330			34.9