I have a spreadsheet, (I know I know) and I can set the crank and the rod to any length I want, and I can set the crank rotation degree step down to .1 degrees. I can set the precision of the piston travel to 6 decimal places.
Tell me the stroke you are using, and the length of the rod, center to center, and I can tell you exactly how much things change with a chang in stroke or a change in rod length.
In the differences we are talking about in stroke and length, I’m pretty sure there is so little difference you will be surprised.
For instance:
Stroke 2.6772 Rod 3.3030
Piston Travel Crank Shaft Rotation In Degrees ATDC
0.000000 0.0
0.000004 0.1
0.000008 0.2
0.000024 0.3
0.000046 0.4
0.000076 0.5
0.000094 0.6
0.000135 0.7
0.000184 0.8
0.000241 0.9
0.000272 1.0
0.000340 1.1
0.000415 1.2
0.000498 1.3
3.3130 2.6772
Piston Travel Crank Shaft Rotation In Degrees ATDC
0.000000 0.0
0.000004 0.1
0.000008 0.2
0.000023 0.3
0.000046 0.4
0.000076 0.5
0.000094 0.6
0.000135 0.7
0.000184 0.8
0.000241 0.9
0.000272 1.0
0.000339 1.1
0.000414 1.2
0.000497 1.3
With this you can see that with a .010” longer rod, in the range pictured, there is no change. At 1.0 degrees of crank rotation. The change at 1.3 degrees is insignificant. .000001 is nothing.
Comments, compliments, criticisms and questions always welcome.