915 shift issues

[r lane]

I track a narrow body car with a short shift but stock shifter with a Sien spring assist. An event at Road Atlanta this past weekend, my shift into 3rd heading up to the bridge would balk 1 out of 2 laps. Then will not go into any gear, you are coasting, cars flying by on both sides, then eventually you find a gear and get going again. This has been an ongoing problem, but intermittently. Feels like I am hitting 2 gears, 3rd and 5th, 3rd and 1st, don't know. I make sure I have the shifter all the way over headed for 3rd against the spring resistance. I don't think a Stomski, Wevo shifter is going to fix this issue. I think the problem is between cup and socket and the little finger inside the gearbox selecting the shift rods. Any enlightenment would be greatly appreciated. Contemplating going with a turbo box this has become such a problem, but would love to find a solution with what I have. Thanks, Bob

[Rosco_NZ]

If the linkages are not work, check engine & trans mounts.
The weight of the engine and trans means they move on the mounts, especially on sticky tires on track. It’s a well documented early 915 problem. Stiffer engine mounts help, full on race cars likely run solid mounts.

[gled49]

Sounds like a shift rod adjustment. Either adjust to the 1-2 side or try adjusting to the 5-R side (I’ve had luck on a few occasions making that adjustment). The 5-R adjustment helps with 2 people, one to hold the lever against the spring pressure while the other makes the trans rod adjustment.

[ClickClickBoom]

Check your tunnel for broken shift bushings…..