I just replaced (well, had someone else replace) the engine in my 06 Solstice.
The engine runs great for the most part (will open a separate question about that), but there is a weird vibration at about 3K RPM. The vibration disappears when the clutch is disengaged (? pedal down == disengaged, I think). It appears to be RPM-dependent, not speed dependent, which is weird since it stops if the clutch is disengaged.
Other potentially-relevant data:
- New Spec stage 2 clutch, pilot bearing, etc.
- Re-used flywheel from previous engine. It's a Spec aluminum flywheel with about 2k miles on it. It worked fine in the previous install (same car).
- Engine seems strong and smooth - it revs fine, etc.
- Probably a different problem: there's a weird rubbing/grinding feel when the wheels are turned to the right. I notice it most when backing out of a parking space or my driveway. It does not happen when turning left. I thought it might be a wheel bearing, but it only happens when the wheels are turned to the right.
The shop that did the engine install thought it might be a bad transmission mount. They offered to swap it out but I was already several thousand dollars in, and it's not a difficult procedure so I thought I'd do it myself. However, I haven't had the time to jack up the car and have a look.
So, my guess-analysis:
- Engine runs fine otherwise, and the vibration doesn't seem to affect revving, etc.
- If it was coming from behind the transmission (driveshaft, differential, etc.), I would expect it to be speed-dependent, not RPM-dependent.
- Flywheel was good before, can't imagine why it would be out of round.
- Bad transmission mount
- Bad clutch install (mind you, it works just fine, though it feels as if the slave cylinder isn't pushing quite far enough - can be "notchy" going into gear)