Icon6 PolyUrethane Motor Mounts Break IN EffectJust installed some 75A Innovative poly mounts on car. Make the cabin and everything inside the car vibrate alot like you need ear protection almost.

Anyone else had these, did the vibration decrease over time ?

How much vibration is expected to go away over time?

 

75A is pretty stiff and are always going to be fairly loud. 60A mounts are plenty for the vast majority of street cars. They will 'mellow' a little with time and miles

Either way, try this and see if it helps.

Add a little poly grease (i.e. the stuff Energy Suspension/Prothane sells) anywhere the poly inserts touch the mount brackets or chassis. Use a jack/jacks to hold the weight of the engine/trans assembly's weight off of the new mounts, then install the mounts and brackets. Torque down all hard points (mounts to trans, engine). Run the mount bolts (the ones that run through the poly) down until they bottom, back off a turn. Let the engine/trans assembly down onto the mounts. Fire the car up, let it idle for a while and get settled in, then torque everything down. For a B or D series, I prefer to do top engine/trans mounts, then rear mount, then front lower torque mounts in that order.

 

You dont need to make multiple threads with the same question.

 

SpAdam,

Thanks for the detailed solution this has brought to mind something else similar that may help my situation as well, similar to what you suggested.