Poly Mounts

[gectek]

has anyone filled thier stock mounts with polyurethane, and if so how hard was it and did it require any special tools.

also what type of compound should i use

[gectek]

srry, just did a search for it and found the compound, but has anyone done it and had good results?

[AaronGTR]

http://www.mcmaster.com/

Part number 8644K11. $26.66 for 1lb of liquid urethane casting compound. It's two part with the urethane and a hardener so you have to mix it together. Work time is 10-20min, but it's really thin and runny at first so it's best to let it sit for 10min before you pour it in or it will leak out and get really messy. Clean the mount really well with brake clean or mineral spirits to degrease it, then tape up one side really well to hold in the urethane until it cures. It takes 48hrs to fully cure so you'll need to be able to let the car sit for a day or two before you put it back in.

I filled the side and rear mounts on mine and it worked really well. Still a little flex for vibration absorption but much stiffer than with just the rubber in the center. I already had the front mount from RSM so I didn't have to do that one. Most people just do the front tranny mount anyway because it's the easiest to get to, and that is sufficient for most people to reduce engine movement without overly increasing vibrations inside the car.

[gectek]

well i was just gonna get both new mounts and do it like that, so my car dont have to sit. i saw you were sceptical about it at first, but u like it better with the poured back one over the stocker? r u still using the rsm on the front?

what might be the advantage of filling the lower tranny mount on the drivers side?

and also if i wanted it to be more flexible couldnt i just get the poly putty that isnt as hard and use it? the 8644k29? then it wouldnt make such a mess

[gectek]

instead of filling the back one, couldnt you just use the stock pattern and make a bracket to bolt another rsm mount to, because the front and rear in design (other than bolt pattern) are basically the same

[gectek]

hey aaron, while ur here what did u notice from filling the side trans mount?

[AaronGTR]

instead of filling the back one, couldnt you just use the stock pattern and make a bracket to bolt another rsm mount to, because the front and rear in design (other than bolt pattern) are basically the same


Nope, the front and rear brackets are totally different. Honestly I wouldn't use another rsm mount anyway. Yes I still use mine and it works just fine, but it's so much cheaper and just as effective to fill them with urethane.


As for why I filled the rear and side mounts too... basically because I had the entire drivetrain out at the time so it was easy to do. It wasn't absolutely necessary and most people wouldn't like it because of the extra vibration. It's just me being anal about details. lol Since I'm putting down a lot of power and torque and I have a stiff suspension and road race the car too, I wanted the maximum amount of control for engine movement I could get. Thats all.

[gectek]

ok, so for minute additions in vibration i should just look at the front and rear

[AaronGTR]

The rear is closest to where the sub-frame bolts to the unibody and will transmit the most vibration into the floor of the passenger compartment. It is also the hardest mount to get to by far. Honestly just the front mount should be all you need to stiffen it up for front to back motion.