Poly Motor Mounts

[karl]

I see Energy has poly inserts for the clamshell mounts on the c10. How do you install these into the clamshell? And how do you get the rubber out?

[mooseknuckles]

i think its a whole new mount....you take the old one off and throw it away

[ray_mcavoy]

Hi Karl,

The two halves of the steel shell are spot welded together (some might be riveted). Just drill out the spot welds or rivets to open up the shell, remove the old rubber insert, and put in the new poly inserts. The frame mounting bolts will hold them back together but you could weld or rivet them back together to make installing them on the frame easier.

Before removing the old rubber inserts, take note of how they're oriented in the shells. There are a couple of protruding tangs on each side of the large through-bolt holes. The inserts have to be positioned correctly for those tangs to mate up with the corresponding notches in the brackets that bolt to the engine.

Edit: Just noticed mooseknuckles reply. I've seen replacement clamshell mounts that do include a new steel shell. But I think those just available with the stock type rubber inserts. And on the ones I've seen, the steel shells look a bit thinner than the original GM mounts.

[karl]

It looks like an insert to replace the rubber from the inside. If so, the shell will have to be split somehow and put back together? Are the BBC and SBC mounts different?

[ray_mcavoy]

No, SBC & BBC are different. They look very similar but the outer shells are a little different and I think those locating tangs I mentioned above might be slightly different too.

I think the SBC clamshell mounts have 4 mounting holes (although some vehicles only use 3 bolts leaving one hole unused). While BBC clamshell mounts have 3 mounting holes.