TLDR: UHMW poly rod to replace AA rubber mounts on LS swap with excellent results.
So.. I had some trashed biscuit style rubber motor mounts( advanced adapters) that I was never super happy with on the LS swap. I ran them for years and they held up ok.. but I was always kinda annoyed by the vibes they give in the cabin. Vibes got progressively worse.. and finally I decided to start looking for a better solution. I considered cutting the mounts off the frame and doing something else like the SBC clamshell style mounts that @Clonestocker did on his. Or perhaps the tube/bushing style that are pretty common.
Ultimately, I didn’t want to make it that much of a project. I already have my hands full with projects and business/work/life.
Searching the interwebs, I found a few examples of dudes using UHMW poly rod in a biscuit style mount arrangement with good results.. one gentleman, describes the process in pretty good detail… found on The Jalopy Journal, titled “space age motor mounts”.
Just so happens, I had some leftover UHMW rod from a body lift laying around. It looked pretty close in diameter to what I would need so I decided to give the little experiment a shot. It cost zero $.. and the worst that could happen is I pull them out and replace with rubber again.
So.. I jacked up the engine slightly and removed the old passenger side mounts. I quickly realized you can’t just drill the UHMW rod and bolt it in there. The hole for the retainer “cup”on the AA motor mounts is too big. After pondering for a beer or two.. I thought I could try to re-use the metal “cups” that are incorporated into the old AA rubber mount. The UHMW rod I had was 2.5” diameter so I took a measurement of the AA cups.. and by the grace of God.. they are almost exactly 2.5” ID..
So I went ahead and took of few more measurements.. height... Settled on cutting the rod at exactly 1” thickness. Then I layed out a paper template to find center and drilled matched 5/8 holes through two at a time.
Onto the “cups”. Went ahead and cut the old AA rubber mounts in half with a sawzall. Then burned the rubber out of the metal with a torch (nasty stuff).. I cleaned up the cups with a wire wheel, washed em and threw a coat of paint on them.
Used a mallet to hammer the UHMW rod into the cups.. and then were ready to go on.
I decided not to cheap out too much.. so I went ahead and bought new bolts/nuts/lock washers… the old AA hardware didn’t look great.
Zipped the mounts back on and snugged them up.
Started the truck up and immediately felt a difference. The idle was smooth and when reved to engine felt much more solid and planted.
After driving a couple hundred miles I can say I’m really impressed with this setup. It really made a big improvement in all the little vibes and reverberations I was getting at certain RPMs etc. much more refined and solid.
Very happy overall
Just thought I’d share
Cheers
So.. I had some trashed biscuit style rubber motor mounts( advanced adapters) that I was never super happy with on the LS swap. I ran them for years and they held up ok.. but I was always kinda annoyed by the vibes they give in the cabin. Vibes got progressively worse.. and finally I decided to start looking for a better solution. I considered cutting the mounts off the frame and doing something else like the SBC clamshell style mounts that @Clonestocker did on his. Or perhaps the tube/bushing style that are pretty common.
Ultimately, I didn’t want to make it that much of a project. I already have my hands full with projects and business/work/life.
Searching the interwebs, I found a few examples of dudes using UHMW poly rod in a biscuit style mount arrangement with good results.. one gentleman, describes the process in pretty good detail… found on The Jalopy Journal, titled “space age motor mounts”.
Just so happens, I had some leftover UHMW rod from a body lift laying around. It looked pretty close in diameter to what I would need so I decided to give the little experiment a shot. It cost zero $.. and the worst that could happen is I pull them out and replace with rubber again.
So.. I jacked up the engine slightly and removed the old passenger side mounts. I quickly realized you can’t just drill the UHMW rod and bolt it in there. The hole for the retainer “cup”on the AA motor mounts is too big. After pondering for a beer or two.. I thought I could try to re-use the metal “cups” that are incorporated into the old AA rubber mount. The UHMW rod I had was 2.5” diameter so I took a measurement of the AA cups.. and by the grace of God.. they are almost exactly 2.5” ID..
So I went ahead and took of few more measurements.. height... Settled on cutting the rod at exactly 1” thickness. Then I layed out a paper template to find center and drilled matched 5/8 holes through two at a time.
Onto the “cups”. Went ahead and cut the old AA rubber mounts in half with a sawzall. Then burned the rubber out of the metal with a torch (nasty stuff).. I cleaned up the cups with a wire wheel, washed em and threw a coat of paint on them.
Used a mallet to hammer the UHMW rod into the cups.. and then were ready to go on.
I decided not to cheap out too much.. so I went ahead and bought new bolts/nuts/lock washers… the old AA hardware didn’t look great.
Zipped the mounts back on and snugged them up.
Started the truck up and immediately felt a difference. The idle was smooth and when reved to engine felt much more solid and planted.
After driving a couple hundred miles I can say I’m really impressed with this setup. It really made a big improvement in all the little vibes and reverberations I was getting at certain RPMs etc. much more refined and solid.
Very happy overall
Just thought I’d share
Cheers
