|July 18, 2011 - I spent most of the weekend on other things, but I did crawl under the MG to take a shot at solving the vibration.|
One of my thoughts was that I might be able to slot the motor mount holes to move the engine slightly. So I was quite happy to see that they were already slotted, and that I had lots of room to move the engine in the direction I wanted to move it.
After some wrenching, levering and jacking, I had the engine tightened back up in my new location. The gap between the body and the offending bump on the block was a bit larger. A test drive showed that the vibration was dramatically decreased. I'm not even sure if it's still hitting - there's still a bit of a rumble under certain conditions, but it seems to be more restricted to certain RPM ranges which tells me I'm dealing with an acoustic resonance. So, good progress then!
tags: motor mounts, interference