Originally Posted by waldoweirdo
Thanks to all for the input so far. I'll check on the numbers tomorrow and post 'em. This whole deal is for a 75 year old pal of mine who is not internet savvy, so I volunteered to help out.
The devil is in the details.
There can be MANY reasons to have a vibration that has nada to do w/the crank balance.
You need to describe in as much detail as you can- like will it vibrate if you are sitting still, in Park, by raising the RPM to the point it does it, or what road AND engine speed(s) the vibe occurs, whether it does it when in gear, coasting in neutral, under acceleration, during steady cruise, etc.
Things that could be involved are the various engine accessories like P/S pump, A/C compressor, W/P, a broken clutch fan assembly, the wrong or damaged flexplate, flexplate balance factor, flexplate fasteners, the torque converter and its fasteners, the motor mounts, the transmission mount, the drive shaft balance, the U-joints, the differential, even tire imbalance can cause vibrations.