Diy Urethane Motor & Tranny Mounts Project

[SERvo]

DIY Urethane Motor Mounts

Time: Two days
Cost: $14
Difficulty: Easy
Tools: Basic

This project has been covered on the net a few times in different cars, but I thought I’d document it for the 240sx while I was doing it anyway. This is only my experience and you might have a different way of doing stuff.

My last trip home from Cali, my shifter was beyond shaking while driving on the freeway. It always felt sloppy, but now it was flopping all over the place and I figured I’d need to do something about the tranny mount at least, and possibly all the mounts. I have more time than money, so when I found out about the DIY urethane mounts you can make with 3M Window Weld, I was up to try it out. Hell, for $14 worth of urethane, it was worth a shot. In the past I’d broken multiple Place Racing mounts in my SE-R and at $50/mount that got expensive quick.

So here’s my write up.

Tools needed:
- 1 tube of 3M Window Weld urethane (the stuff I used looks like this and was about $14 at Checkers - http://www.radiantphotography.com/MiscStuff/3mwindoweld.gif)
- caulk gun
- jack and stands
- basic tools (sockets, screwdrivers, etc)
- breaker bar (if mount nuts are old and stuck)
- penetrating oil (WD40, etc)
- degreaser (to clean mounts with)
- block of wood
- heat gun (if working in the cold)
- rubber gloves
- something to drink

Process:
1. Jack up and secure car on stands. I used the tow hooks under the front bumper.
2. Place jack with block of wood under motor where it meets the tranny, just behind the cross member (pic 1 & 2). I had to position mine slightly to the driver’s side to make the motor come up and down evenly. Play with the positioning to eliminate the motor leaning one way or the other. Motor needs to come up evenly to remove mounts from each side of motor. Keep the motor lowered for now, just have the jack in position. Don't position the jack under the oil pan cause it will jack the front of the engine up and pinch wires between the motor and firewall. Plus you won't get the tranny up high enough to free its mount.
3. Spray bolts on upper and lower sides of mounts with WD40. Also hit the four visible bolts on tranny mount (2 facing ground, 2 facing rear of car). There are also two tranny bolts above the mount support (long metal bar the tranny sits on). You can WD them now or wait until the motor is jacked up.
4. On top driver’s side of engine bay, I found it useful to remove the PAIR valve bracket and move it out of the way (pics 3 & 4). Allowed me easier access to the driver’s side mount.
5. Remove upper bolts from engine mounts (one 12mm and one 14mm on each side). (pic 5)
6. Remove lower 14mm bolts on mounts (1 on each side). I had a hard time getting a straight extension in there because of the lower control arm bolts sticking out toward the rear. I ended up using an extension with a knuckle-joint at the end to get the socket square onto the nut. Otherwise it might be at an angle and strip the nut. Those bitches were on there tight! Had to use a breaker bar for driver’s side and my air impact and breaker for pass side.
7. Once engine mounts are unbolted, head to the tranny mount. Remove the four 12mm nuts and two 14mm nuts on the tranny mount (pic 6). Also remove part of the exhaust hangar bracket to give you more space, which has two 12mm nuts.
8. Jack motor up enough to free the tranny and engine mounts. Take care to watch your motor and make sure you don’t pinch any wires between it and firewall as the motor comes up.
9. Work the mounts out of their mounting holes. I found it was easiest to remove and replace the engine mounts from the front underside of the engine, rather than the rear. The tranny mount just pulls up off the brace and then out toward the front of the car.
10. Once mounts are out, it’s time to clean them with some degreaser and a brush. I used a citrus-based cleaner, but I suppose any degreaser, Simple Green or carb cleaner will do. After degreasing well, rinse them with water, then dry them as best you can. I sat mine in front of a box fan for a bit and it did the trick. Sh*t, we live in the desert, put them on your driveway for an hour.
11. Once dry, start filling them with urethane. Place mount on cardboard and focus on filling one side of the mount. Then flip it over to fill the other side. I filled mine at night and the urethane was cold and VERY hard to squeeze out. I suggest doing this during the day and leaving the urethane tube outside to warm up in the sun, or do as I did and use a cheap heat gun to warm up the tube.
12. Most websites said to allow 12-24 hours to cure. One said to put the mounts in your oven for three hours at like 125 degrees. No way in hell I was gonna get urethane all over my stove so I left them in the front yard for 24 hours. IT WASN’T ENOUGH! Once I installed the mounts and lowered the engine back down I noticed a very slight leak from the mount (pic 12). It was minor, but made me aware that another day of curing might have been perfect. They were cured enough to drive so I suppose they’ll cure up fine in the car.
13. After curing, reinstall the mounts. Remember the front mounts on a stock 240 will go back in easier from the front underside of the engine (pic 13). Trying to do it from the top or back underside just didn’t work too well for me.
14. When reinstalling the mounts, before lowering the engine, make sure they are locked in place. They have nodes on them that the engine bracket has to align with. Make sure these bumps and their respective mount hole are lined up while lowering the motor and before tightening everything down.

That's about it.

Side note:
When I removed my driver’s side mount, it was TRASHED. Broken in two and had rusty fluid in it. I just cleaned the broken surfaces really well while degreasing everything, then used super glue to piece it back together. I figured it would hold well enough while the urethane cured, which would then hold everything in place once it was dried. Seemed to work perfectly.

Impressions:
I had read that the car would have rattles and buzzes at idle and I was fine with that. Having racing urethane mounts before in other cars, I’m fine with buzzes.

But, my test drive had NO buzzes at any RPM, nor did my shifter flop around anymore, at any speed. Not surprisingly, the motor feels a lot peppier and more responsive when the throttle is punched. Car seems to be more ass-happy now and breaks loose a bit easier in corners, most likely since the power is finally getting the wheels more efficiently. I suspect this is what the car felt like when new.

It’s not a fascinating fix, but definitely worth the money in my opinion. My mounts don’t look JDM tyte, they don’t help me get laid and the lack of bling will sacrifice some third gear VTEC performance yo, but it cured my floppy shifter, tightened up the engine response and kept some coin in my pocket. And there’s a good chance I won’t have to replace mounts for a very long time, if ever.


Pictures, part I

Pic 1 & 2
Jack placement on tranny/engine junction (front and back angles)



Pic 3 & 4
Pair valve bracket before and after removal



Pic 5
Upper mount bolts (12mm and 14mm)

[SERvo]

Pictures, part II.

Pic 6
Tranny mount (four visible 12mm nuts from mount to x-member, and two 14mm nuts from mount to tranny)


Pic 7
Dirty mounts! The driver's side one was torn in half....lovely.


Pic 8
Clean mounts ready to be filled.


Pic 9
Filled mounts


Pic 10 & 11
Detail shots of the driver's mount and tranny mounts filled with urethane.



Pic 12
Wasn't quite cured enough after 24 hours. Small leak after lowering the motor, but it's all dried now.


Pic 13
Remove and reinstall mounts from the lower front of the engine bay.



Edit - 5 Days Later!
Well, it's been a few days and I'm still really impressed. The mounts are fully cured and there was a slight stiffening from day 1 to day 3 when they were finally cured. The car still doesn't buzz, but the motor vibration is a bit more noticable. I'm a fan of this mod and plan on doing it to my Toyota truck soon.

Anyone who wants a ride to feel the effects, let me know.

[haveblue]

wrap em up with masking tape or painters tape, that way you can really fill them up. and let them dry for about 3 days because the stuff in the center takes a while to cure.

how the epoxy floor holding up btw?

[LV240S14]

best thread on here in monthes, I might have to call you sometime soon to do this to my stock motor mounts. Thats just so cheap.

[myowncasualty]

i did this on my car.....huge difference over stock....and i actually used almost 2 full tubes of the stuff...well all in all im never going to wast money on buying aftermarket ones again

[SERvo]

The epoxy floor is holding up nicely. urethane wiped right off.

I tried tape and in the end i was worried about being able to remove the tape after the urethen dried. After fiddling with it for 1/2 hour, I just decided I didn't care about finished edges and I figured the mount would be filled in enough. I'd love to see how they look when someone fills in the whole thing though. Try it and post up!

Thanks for the "best post" comment. I figured it was about time I contribute something of slight value to the forum, been around for awhile now sucking info from other people.

[2k5 Rex]

Ima have to do this soon... here is another variation I found in NICO... very useful if you have issues with hood clearance-

http://forums.nicoclub.com/zerothread/204560