I have two 58 Limiteds one of which I drive often. I've had this Riviera sedan for over ten years and after everything I've tried, engine vibrations upon acceleration from a stop are very loud. Both LImiteds have this problem but the closed-cabin model 750 is by far worse. After adding heavy insulation to the interior, adding new rubber body mounts doubled in thickness, and new engine/Flight-Pitch mounts nothing helps. I have redesigned the exhaust system, after six different attempts, to locate all mufflers behind the rear axle. Now I've reached the point of needing to have the 364 rebuilt due to oil consumption. The most interesting challenge here is that I have driven a 58 Limited 750 in Texas that did not suffer this noisy problem. No one, thus far, seems to know the answer of how to silence this transfer of vibration from the engine into the interior. As I study the service bulletins for the 58 Buicks I learn these cars were plagued with noise complaints. In 1962, Buick moved the placement of the nailhead engines forward on the frame to help quieten them. In addition, the engineering of the Buick Torque-Tube system may contribute to this noisy problem as these cars are pushed through the engine mounts.
If anyone has any insight or experience in solving this noise issue, I would be most appreciative.
Tom Helms
Air Poise
Pensacola, FL