Making Your Own Solid Motor Mounts

By Steve Hoult.

The Original Article is here

I had seen an article detailing how to do this job floating around the Internet and although it was written about the Nissan SE-R I though it should work for the MR2 SC.  The basic info from the original article led me down the right path. I'm just adding pictures and my own text. Since I was only concerned with the back and forth movement of the engine during accel and decel I only did the front and back mounts.

Here's what you need..

    (2) Jack stands

    (1) Hydraulic Jack

    17 and 14 mm sockets and wrenches

    Hammer or Air wrench

    1 Pound can of Flexible Urethane.Casting Compound (this is really enough to do four mounts)

    48 hours with your MR2 in the air or a spare set of Engine mounts

If you don't have the jackstands and Hydraulic jack, don't do this. I don't want to hear about it. 

Okay...First log on to the McMaster-Carr web site. Your looking for Flexible Urethane,. They have a terrible layout and it's hard to find things, but here's what your looking for. (three choices). To order, just enter the part number in the search window. I purchased both the 60A and the 80A planning to do two sets and trying each. 

8644K24     Flexible Urethane     Shore 60A     $24.14

8644K11     Flexible Urethane     Shore 80A    $20.88

8644K18     Flexible Urethane     Shore 94A    $20.71

Shore 60A is the most compliant and 94A is a hardest. If you're target is a full on race machine then go for the 94A (or machine mounts from billet Aluminum, it'll be much lighter). and do all four mounts. If it's going to be a daily driver then go for either the 60A or 80A. I used the 80A on only the front and back mounts and I notice quite a bit more noise and vibration in the cabin. Not terrible, but I like those kinds of noises. 

One last thing to decide. If you can't do without your car for at least two days you need to find a spare set of engine mounts. The mounts need at least 48 hours to cure at room temperature. One other thing to consider is that it is having an extra set of motor mounts makes it much easier to reassemble as well as safer. However, since the engine is held in with the side mounts it isn't that difficult to do without spares. With that said, let's start now.

To remove your motor mounts you'll need to jack up the rear of your car so that you can slide un and work easily. You'll need to work forward of the engine so it needs to be fairly high. Next put the hydraulic jack under the transmission and raise it to it is tight against the gearbox, but not lifting the car. The easiest way to get at the rear mount is to remove the the cat and muffler. This can be done with just four bolts. Undo the two bolts that connect the cat to the downpipe. Now remove the two bolts holding the drivers side muffler mount to the trunk floor. The entire system is now loose and needs to be slid out of the passenger side muffler mount. Slide it towards the driver side until loose and the move it out of the way.  The rear engine mount is now  easy to work around.

Here are the stock mounts removed from the car. You'll notice that they both have fairly large voids. These voids are what allow the motor to move and isolates the vibrations from the cabin. By filling these voids with Urethane we will eliminate the isolation factor and limit the rocking movement of the engine.

To prepare these mounts for filling you need to clean these up very well. Use a cleaner to remove the dirt and gunk. Make sure to rinse and dry the mounts very well. The bond between the poured in Urethane and the stock mounts depends on the cleaning job you do at this point. Once you are happy with the cleaning job, tape one side of each mount up. You'll notice that I cut out for the bolt hole, DON'T do this! All that I accomplished by doing this is to waste a bunch of liquid urethane (check the next picture) and almost ending up with not enough urethane to fill it up!

Here is the filled mount. If you look carefully in the picure under the mount you'll see a pool of urethane. This is because it's leaking out of the hole I so carefully cut around the bolt hole. This stuff has incredible flow characteristics and will seep out of any small hole you leave, so make sure your tape job is hole free.

The mounts will be set up in an hour or two and will be cured in about 48 hours. Once they are cured, remove the tape and take a drill bit and clean out the bolt hole. You now have solid motor mounts to install in your favorite toy!