Motor mounts cause knock..

[Turbo Archie]

Yep,

My pass mount failed and the motor sagged on that side. This made the crossover collector flange on the pass header hit the frame on hard launches. This caused false knock and pulled all the timming out going down the track.

I found this while installing a 3.5" down pipe. I thought the stock down pipe was hitting the a-arm, which it was also.

I will post track improvements after I go on tuesday.

Oh, and new mounts were $23 for the pair.

[87natty]

Where at?

[SuperSix]

Yep,

My pass mount failed and the motor sagged on that side. This made the crossover collector flange on the pass header hit the frame on hard launches. This caused false knock and pulled all the timming out going down the track.

I found this while installing a 3.5" down pipe. I thought the stock down pipe was hitting the a-arm, which it was also.

I will post track improvements after I go on tuesday.

Oh, and new mounts were $23 for the pair.

Why not Poly mounts? I don't need/want them, but your car's a bit more stout than mine.

Natty - That's the going rate for India-made mounts @ Autozone, Advanced, etc...

[87natty]

I had poly bushings in my El Camino and they are not very forgiving as far as comfort and vibration go. I would also be worried about the poly mounts adding to false knock signals as well. I also feel that poly mounts would shake the hell out of my car.

[Be4u]

Natty, nah, the occasional vibrations are minor. Dont believe the hype. When I felt my first vibration I was like "thats it?!?!?"

[Top Speed]

I agree.  I don't even notice my poly mounts.

[Turbo Archie]

I'll post a pic of the bad mount. We were at my friends shop doing the DP. There was no way we could have made the 3.5" work with the old mount.

I have HR mounts for my 4.1 in the '86 I have. This car is a beater and the mounts were a last minute fix so the cheap $23 mounts will work fine. He did point out the differance between the two. The pass mount was orig and the dr was a replacement. The orig brackets are thicker and the rubber is better on the orig.