Bits and Pieces
Builder's Tip - Installing Engine Vibration Mounts
Putting the lower two bolts through the vibration mounts when installing an engine can be difficult. Aligning the flexing mounts while trying to hold in place one or more washers between the engine and the two-part vibration mount assembly can be extremely difficult.
Struggling to persuade things into position sometimes benefits from taking a break. On this occasion, at the end of a two-day obligation to something unrelated to the aircraft, a light came on. The solution was to take one of the old engine mount bolts and grind it to a point. Using a 3/8-inch drift would have worked if we could get it in place, but there was insufficient space without removing the battery, battery mount, and a whole load of wiring.
Unmodified engine bolt
Grinding an offset point allows the bolt to be rotated for the optimal angle for pulling the components into alignment.
As you can see, leaving sufficient threads on the bolt will also allow it to be screwed in, and more importantly, unscrewed to replace it with the new bolt.
These bolts are expensive, but they're routinely replaced when installing new engine vibration mounts. Maybe you can get an old one from your local mechanic. Just check for a useable length. You'll also be able to avoid wear and tear on the new bolt set by getting perfect alignment prior to installing the pristine bolts.