Solid motor mounts... yay or nay?

[fishsticks]

When I do my front gears, I'm going to go ahead and tackle the motor mounts at the same time. I'm nearing 100K miles with a lot of bouncing around during the last 20K or so... I figure it's time. I'm also trying to stamp out a problem where the front couple bolts on my exhaust manifold like to repeatedly back off a couple turns over time.

Given the abuse we put on our motor mounts, I looked briefly for some polyurethane mounts and found (surprise) nothing. Since our mounts are so simple, I started thinking about fabbing up some solids or semi-solids.

I've heard the horror stories about solid mounts, but I run them on my F-Body, as it likes to eat standard mounts. Obviously the vibration is increased, but I've suffered no other ill effects. They're great for combating mount fatigue/destruction from hard launches and hard shifts with a T-56, but this is a different ballgame.


Am I asking for trouble? I figured I'd get a length measurement and fab up some simple solid mounts out either square or round tube, possibly with some poly bushings on the ends for a little shock absorbsion.

[bartonmd]

ewww... Solid motor mounts take away a lot of the shock absorbsion of the drivetrain when you downshift, or pin the throttle, or more importantly, the locker locks up, or the wheels are spinning, then catch traction... Basically, solid motor mounts are just plain old hard on shafts, gears, axles, bearings, and to some extent crank/rods/pistons in the engine, as you get the back torque shock...

Poly bushings, maybe, but I personally wouldn't hard mount a drivetrain on something I off road...

Mike

[The Roadie]

I just look on motor mounts as another consumable. In my case about 75K miles. Actually the driver's side was probably OK, but I bought both. Somebody could try my takeoff on their passenger side for a cheap experiment.

[fishsticks]

Right. I kinda figured it was a bad idea for this application. We'll just throw this idea into the scrap bin...

[Opeth]

Take it from me, someone who has dealt a fair share in playing with motor mounts on my tuner car...

EVERYTHING in your dash will begin to rattle itself loose enough that at certain harmonic speeds will vibrate annoyingly (500-1,100rpms is the usual range) above that with poly you don't notice anything.

Poly mounts will break in slightly, but you will still get rattle and a lot of vibrations. Soild mounts, no one wanted to ride in my car when I had them. Idling at stop lights, quite annoying especially with an aggressive cam. It was by no means a daily driver because it was heavily modded, and I was breaking half shafts every few weeks or something else was acting up.

IMHO.... buy some fresh OEM mounts and save yourself the headaches!

[fishsticks]

Take it from me, someone who has dealt a fair share in playing with motor mounts on my tuner car...

EVERYTHING in your dash will begin to rattle itself loose enough that at certain harmonic speeds will vibrate annoyingly (500-1,100rpms is the usual range) above that with poly you don't notice anything.

Poly mounts will break in slightly, but you will still get rattle and a lot of vibrations. Soild mounts, no one wanted to ride in my car when I had them. Idling at stop lights, quite annoying especially with an aggressive cam. It was by no means a daily driver because it was heavily modded, and I was breaking half shafts every few weeks or something else was acting up.

IMHO.... buy some fresh OEM mounts and save yourself the headaches!

As I said... I have first hand knowledge of solid motor mounts, as I have a set in my Camaro. Fortunately F-bodies are already rattle traps...

Annoying interior I can convince myself I'll deal with. Frame fatigue I can't.

Thanks for the thought though.

[Opeth]

Sorry, I am not sure how I overlooked that in your original post, DOH! But at least now you know