Sorry to hear about your blower problem. I have owned a vortech SC since 93 and still run it on my 5.0 to this day. It was an "A" trim for about 5 years with many 12.8 1/4 mile passes on it when I decided to step it up a bit. I sent it back to vortech had a "s" trim wheel installed in the same case and the guy that inspected it said it looked brand new. Now for the last 2 years its been running at or over its max impeller speed with no problems in the low 11s. Cant seem to reach my goal-10s. I do know several others running vortechs and have never heard of your problem- even on terribly abused blowers. Good luck on the fix!