Solid motor mounts on a driver?

[malibu9in]

Running a ls in my Malibu. Motor shakes so much now valve cover hits heater box. Motor has settled I guess. Too much rubber mount. Anyhow. Can I run soild motor mounts? It's a driver. 600 hp or so. 6 speed. I want zero movement. Thanks guys. Jason

[moreHP]

I have run solid motor mounts in a street car with no problems at all. Just make sure you have a rubber mount under the trans. There has to be some flex available.

[astroracer]

If you go solids expect a LOT of engine vibration and NVH stuff to start happening. I would much rather see you simply install a torque limiter strap. Leave it a bit slack so going down the road it is loose so you don't get any harmonics through it. :)
Mark

[ehummelman]

How close is the heater box to the vc? I would question why you're getting so much shaking to begin with. A little is normal, but enough to cause the engine to be hitting stuff is a bit much unless that heater box is already nearly touching.

[Chevelle598bb]

I have used them before but poly motor and trans mounts are better. Plus it solid mounts can cause stress cracks in the cradle area. With poly you get the best of both worlds; no movement and no vibration.

[astroracer]

I have used them before but poly motor and trans mounts are better. Plus it solid mounts can cause stress cracks in the cradle area. With poly you get the best of both worlds; no movement and no vibration.

Disagree... The rubber trans mount on my '02 TA was broken when I bought the car. Everyone said but on a poly and it won't break. Did that. The poly mount transmits a LOT of harmonics into the car. Especially the shifter. Lots of buzzing and clattering that wasn't there even with the broken rubber mount... Polys are much stiffer then rubber so they have to transmit more vibration. No way around it. :(
Mark

[Vegas69]

There is no answer for this question. It comes down to your personal tolerance for harmonics.

[malibu9in]

I did the swap about 6 years ago. No one was really making any conversion mounts and stuff so I went with some eBay set up. It's got a very roudy cam. The mounts have alot of rubber in them. When the car is not running there is a solid 5/8 inch clearance. But once it idles then it's very violent. I also
Noticed one o the headers is touching at idle. A torque strap might work. Looks a little unattractive. But it's a ideas. Thanks for the replies guys.

[ehummelman]

Probably not what you want to hear, but can you modify the heater box at all to give yourself some room? Cut off an inch or so and refiberglass?

[68Formula]

Haven't tried it yet, but some people use solid on the driver's side and rubber on the passenger.

When the motor torques at full throttle, it's going to put the driver's side in tension and the passenger side in compression. Poly or rubber mounts handle compression much better than they do tension. Thus the solid mount on one side would limit the rotation under load (also prevent a lot of slap back when coming off the throttle) and handle tension better, while the rubber mount on the other side would help dampen vibration. If doing this, one would probably want to keep the trans as rubber as well.

[vette427-sbc]

Ive got solid motor mounts on my vette and my fathers '55 chevy... No vibrations or other supposed "issues" with running solid motor mounts. A properly balanced motor should not vibrate a car. The chassis stiffening is a nice benefit as well.

[clayton25]

had solids on my mustang when i first bought it, vibrated the whole car like hell after 3k. put in poly motor n transno more vibration.

[Scott Parkhurst]

Okay- I've done this for many years with many cars.

Solid mount on the driver's side.

Rubber mount on the passenger side.

Poly trans mount.


This setup works and is livable in a street car. My wagon is a 545hp/6-speed setup and has been running this way since I put it together. I beat the crap out of it and drive it on the street a lot. It's the way to go.

Just don't do burnouts in reverse- it'll rip the passenger one in half. Don't ask me how I know this...

[rob07002]

Okay- I've done this for many years with many cars.

Solid mount on the driver's side.

Rubber mount on the passenger side.

Poly trans mount.


This setup works and is livable in a street car. My wagon is a 545hp/6-speed setup and has been running this way since I put it together. I beat the crap out of it and drive it on the street a lot. It's the way to go.

Just don't do burnouts in reverse- it'll rip the passenger one in half. Don't ask me how I know this...

Bingo! Curious about the reverse burnout though??

[mikeybigblock]

I have always run solids and a rubber trans mount and I have never had a problem.

[malibu9in]

I can modify the box. ALOT of work. I have another issue of the headers touching now. I just want the damn motor still. I think it's too much rubber mounts for the torquy motor. Thanks
For replies. Looks like a poly trans and solid mounts it is.

[LS1NOVA]

Using solids and would not go back.

[66larkgs]

i like that solid mount on one side idea.. never heard of that but eliminates the need for a saftey strap.
love it!!!

[Scott Parkhurst]

Bingo! Curious about the reverse burnout though??

Don't know why it happened...but it did. I dropped the clutch a bit too aggressively in reverse and lit the tires up. No big deal, right? On thw way home it felt a little weak, but was running fine. I took a peek and sure enough, the rubber mont on the passenger side was ripped in half. Swapped it out for a new rubber one and have had no issues since.

[gearheads78]

I have run poly on a few cars. Not near as much NVH as solid but a good bit more than rubber. Great compromise for a street car IMO

[David Pozzi]

I did a quick reverse to "scare" a guy who sat on my front fender. It tore reverse out! It was a Saginaw 4 speed.
I ran solid mounts for years,a little more vibration but it was a balanced engine and not too bad. I DID have a lot of problems with the engine bracket to frame bolts coming loose. I switched to nyloc nuts on fine thread bolts, still came loose. I finally double nutted all 3 on the left side. I was doing a lot of autocross and the on and off cycles are hard on motor mounts and on clutch discs, I tore a lot of them up too until I got an L88 disc.
David

[vette427-sbc]

Thanks For replies. Looks like a poly trans and solid mounts it is.

I would still run rubber on the trans. The frame will flex, and you dont want it flexing your trans case. I run a rubber trans mount with my solid motor mounts like others have mentioned.

[MonzaRacer]

built my 70 Monte with healthy BBC402, solid mounts on engine and used to be able to get solid rubber versus hollow rubber trans mont throught AutoZone,,,will probab ly make solids for my Monza and use poly trans mount, only issues i HAD WAS AFTER BIG BLOCK REPLACED SBC THE 3 IN ex had a drone that was awesome AND annoying before Ishut off. Engine just was LOUD, just no out of pipe end.