Originally Posted by
JieM
On this radial, cylinder #1 is working with a master rod and cylinder #2 and #3 are working with a slave rod. That is the reason, combined with the S magnets at 120° - 120° - 120° the ignition timing is NOT the same for each cylinder. Out of the box, ignition for cylinder #1 is 45° BTDC (even this value is too high for me), and 52° and 38° for the 2 others. Best result for me is 30° BTDC on EACH cylinder. And that is unfortunetly not the case with this saito product.
Note : I have modified my engine to have 30 degrees BTDC and it works really smoother.
JM
I am fully aware of how radial engine rods are designed.
Unless the bores for the slave rod link pins are mislocated in the master rod, there will be no variance in the relationship of the TDC timing of the crankshaft for each individual cylinder. Nor will any degree value BTDC and ATDC be affected.
What changes is the relationship of the piston travel in the bore before and after TDC as well as the "dwell" at TDC. This can affect the effective ignition timing, but not in crankshaft degrees.
However, the relationship of #2 and #3 cylinder pistons in bore travel should be the same as long as the rotational direction of the crank remains the same.