Rear Motor Mount Insert by F 500 Sport

6 minute read

Rear Motor Mount Insert

Compliments of F 500 Sport @ fiat500owners.com

6-17-2013

This is a brief write up for pouring 2 part urethane into the rear dog bone (motor mount). The kit is available from Energy Suspension Parts . com. This mount is almost 100% responsible for keeping the engine and transmission from moving front to back while accelerating/decelerating. With the lower mount out and only the transmission and front mount holding the engine in the motor can be rocked back and forth with very little effort. Also, if you drive aggressive and you keep your hand on the shifter you can feel the engine movement through the shifter cables.

This is time consuming and the dry time is 36 to 48 hours to fully cured. If you decide to do this it would be difficult to reverse. You may want to price a new lower mount before you start. That is the bad news.

The good news is this worked out very well, torque steer is reduced and resonating from the engine is minimal. You will feel some resonation ( is that a word ?) on start up, a bit at idle, and during take off. The later being the most noticeable to me. At high speeds I feel and hear no difference. If you have done mounts before you will know what to expect, and as with anything, it is a trade off. A bit of comfort, for a bit of performance.

A few things to consider; Power Flex makes inserts for the euro version. The rear mount looks very close, but the rubber insulator is a bit different. If they were to come out with inserts for the N/A cars tomorrow I would highly suggest that. The install is the same, no dry time and it would be completely reversible. I knew I would not want to reverse this so I went all in. Plus I got no patience to wait for the aftermarket to catch up. 

So with out any more delay here is what you have;

I used ramps, set the brake and chock the tires. The long bolt will not clear the exhaust so you have to drop the splash pan and the front of the exhaust. 2 flange bolts and 1 bracket at the motor, and the first hanger. This gives you enough room to work. The mount is 2 bolts and it drops down. It does not hold the motor up, so no worries of it dropping. Once out clean with a de-greaser if necessary and then soapy water. As far as the urethane pour and prep follow the directions on the Energy suspension site. 

I have some suggestions and a few pics below; 

1. The manufacture advises not to mix small amounts, the kit is pre measured by weight. Not being one to listen I mixed a smaller amount by weight ( food scale ) and it worked out fine. I did this because I may choose to do the other mounts.

2. You will see where I taped the mount to seal it. This was no where near enough tape. the urethane will leak and it is messy to work with. USE the sand box. Theu suggest it for a reason. It will make your life easier.

3. They suggest mixing for at least 2 minutes, I would double that. The mixture actually will thin out considerably before it starts to thicken up. If I do another mount I would increase the mix time and wait 5 minutes before I poured. ( depending on weather conditions ) 

4. Once you tape and set the mount in the sand, pour the urethane and watch it for several minutes because if it does leak you will have time to top it off with your left over mix.

5. DRY TIME, in 24 hours the urethane will set up BUT most likely not be fully cured. Use any spilled urethane to test if the product is fully cured. Fully cured urethane is very tough and resilient. It will not break apart. 36 to 48 hours to be safe. 

6. I used small stainless measuring cups I got at wall mart, or use a small paint mixing cup IF you don't mix the whole kit. 

7. I used 80 duro-meter urethane as recommended by the supplier.

If you wont miss the car for 2 days this really isn't that bad, absent an up graded mount or inserts. The more aggressive you drive and the more power you make, the more you will appreciate a stronger rear mount.

Instillation is straight forward. CHECK torque specs from a Fiat service manual and button everything up.