Engine Mounts

[KUMARB]

1.  Is there a difference between right and left mounts?

2. What is the purpose of a bolt mounted upside down inside the mount?

While redoing my car, I installed the same new mounts on both sides. These mounts were for the left side. The old left and right mounts on my car looked kind of identical, and I assumed they were the same. Do I need to buy a correct right side mount to do the job right?  I had a collapsed right mount which allowed the exhaust manifold to drop and rub against the idler arm mount, and in the process cracked the manifold.

Your comments are very much appreciated.

[ja17]

Hello,

The upside down bolts with plates are to keep the engine in check.  They are mechanical upward stops so the mounts will not be pulled apart if the engine is moving upward for some reason. Consider that  the entire engine and transmssion  tries to rotate under load. One mount is pulled and one mount is compressed during acceleration. At rest, both mounts are compressed from the  weight of the engine.
I believe the mounts were different at one time. Probably the hardness of the rubber (duramoter) varied on each side. Not sure if this is still the case. Using the same should not make much difference.