I have a rebuilt Sprint V engine that jumps out of 3rd into the neutral position between 2nd and 3rd. The gearcross is brand new and the selector arm protrudes by the specified 1.5mm above the face of the selector box.
According to my reasoning the gearcross does not engage enough in the 3rd gear. And since the selector arm can't protrude any more, the problem should be with the 3rd gear.
Logic tells me that the mid section of the 3rd gear should either be thicker, or the distance (depth) to the mid section should be smaller. I have now measured 10 x 3rd gears, and the thickness of the mid sections are all the same and the depth to the mid sections are all the same.
Thus, for the gearcross to engage more, the 3rd gear will have to move forward. And to achieve that, I will have to use a more modern driveshaft where you can put spacers behind the gears in order to move them forward.
Is this the (only) solution, or do I have it totally wrong?