Prothane Bullet Motor Mount install (w/pics and vids)

TacoBill · 12-24-2007, 01:41 AM

This ‘How-To’ will cover the installation of the Prothane motor mounts.

The installation of these mounts will firm up the rigidity of the engine dampening as compared to the factory fluid mounts.

Prothane currently offers these mounts in either Red or Black polyurethane bushings. There is no difference in hardness between the 2 colors.

Tools required:
13mm & 15mm sockets
8mm Allen head socket
Universal joint adapter (swivel socket)
Socket extensions (longer the better)
7mm wrench or deep socket (for Negative battery terminal)
Torque wrench capable of up to 41 lb-ft.
Anti-seize lube

Estimated install time:
1-2 hours

Out of the box:

Installation:
1. Jack the front end of the car high enough for you to have access underneath. Always use jackstands and wheel chocks at the back tire.

Note: Take a look in your engine bay and see what components (if any) will need to be loosened/removed when the engine is jacked up. In my case, I loosened the C&L CAI heatshield just incase.

2. Disconnect the Negative battery terminal. This is due to the fact that the starter is very close to the Passenger side engine support bracket. It’s primarily for safety.

3. Doing 1 mount at a time, starting with the Drivers side, locate the factory motor mount.

4. Loosen the center engine support isolator nut and the 2 side mounting bolts, but do not remove at this point. Be sure to adequately loosen these fasteners.

5. The engine will need to go up approximately ¼” to replace the mounts. Using a floor jack, I used a piece of 2x4 wood and carefully placed it under the oil pan, just forward of the drain plug. Be careful not to place the 2x4 under the drain valley of the drain plug.

Jack the engine up only ¼” .

6. Locate the engine support bracket and remove the 4 bolts attaching it to the engine block. Use of a swivel socket and long extensions may be necessary.

7. Remove the center engine support isolator nut and the 2 side mounting bolts (from Step 4) and carefully remove both the engine support bracket and the factory motor mount out from under the car.

8. Side by side comparison.

9. Position the new Prothane mount into position (there is no left/right or forward/aft orientation) and hand tighten the 2 side mounting bolts (re-use the factory bolts).

Also, re-install the engine support bracket onto the engine block using the same factory bolts. Torque these bolts to 41 lb-ft.

10. Apply anti-seize lube to the supplied socket head bolt (with the supplied silver flat washer) and install it though the engine support bracket and the Prothane mount, hand tighten only.

11. Lower the engine back down onto the mount.
Torque the 2 side mounting bolts to 41 lb-ft.
Torque the center socket head bolt to 30 lb-ft.

(And yes, that’s my custom Pocahontas fender cover.)

Drivers side complete!

12. Passenger side. Installation is the same as the Drivers side with the following exceptions…

The top-aft fastener in the engine support bracket is a stud bolt. Nothing was attached to mine; deep well socket is needed to remove this bolt.

Note: Take note on how close the starter cable is to the bracket; this is the reason why the Negative battery cable is disconnected.

The top-forward fastener in the engine support bracket has a ground cable attached to the stud bolt. The cable must be removed first prior to removing the stud bolt. Access will be tight because of a wire conduit, but it can be done.

Reconnect the Negative battery cable and check the engine bay for tools before starting the engine.

Installation complete!

Start-up - rev video: hood open

Start-up – rev video: hood closed

Final thoughts...
I'm very happy with them. It has the perfect amount of 'feel' of the engine, not too harsh and not too mellow (like the stock mounts), best description is that it feels 'tight'.

My initial reaction to the Prothanes in JedCranium's Roush was a lot more 'wow!' possibly because he's running cats, thus any addt'l vibrations can be felt alot more. On mine, with the O/R-H, it already vibrated the interior to a degree, which is the reason why I'm guessing it's not a huge difference.

In reality, only a slight vibration is felt on start-up and some during low rpm driving. What is very noticable is that the engine no longer torques side-to-side when revving it up, but rather the WHOLE car now can be seen and felt torquing (maybe 1/2").

Burnsy · 12-24-2007, 01:53 AM

awesome write-up as always...

Bluestar · 12-24-2007, 01:56 AM

Outstanding write-up as usual TB, Thanks again.

ohnoesaz · 12-24-2007, 02:24 AM

Awesome write-up...

I have a question... I did a headers install a few weeks ago. I found that when I went to re-install the engine brackets that I couldn't get the bolts to want to go back in, despite the holes seeming to line up perfect. Did you experience anything like this or have any tips for it?

Also let me add that I think a phone book on the jack instead of a piece of wood is better as it will contour to the oil pan very well and cause a lot less stress.

Thanks bill.

ratnacage · 12-24-2007, 02:26 AM

I asked this in another thread (under 4.6L specific). Did you notice a reduction and/or elimination of grinding into 2nd under hard acceleration? I have the stock mounts and occassionaly get the grind.

nineinchnail1024 · 12-24-2007, 04:09 AM

Quote:

ORIGINAL: ratnacage

I asked this in another thread (under 4.6L specific). Did you notice a reduction and/or elimination of grinding into 2nd under hard acceleration? I have the stock mounts and occassionaly get the grind.

I have the prothanes and I've found that I get into gear MUCH easier during acceleration on the 1/2 and 2/3 shifts.

Taco: I found it damn near impossible to set the proper torque on the bolts that mount the brackets to the block. I ended up going with german torque measurements (goodentight) for some of them.

Also, be SURE you have some combination of 3/8" drive extensions that adds up to at least 20" if you want to reach the top of the motor mounts.

mygt500 · 12-24-2007, 05:40 AM

Great write up Tacobill!!!!!!!!!!!

Rubrignitz · 12-24-2007, 11:42 AM

Yep, another great write up. I had issues after the long tube install and Steeda HD mounts make everything better. It does just feel "tighter", like a performance car should. No more bucking and shifting. One of my best mods I think...

Rubrignitz · 12-24-2007, 11:45 AM

HA! just watched the video. Your shaker doesn't "shake" anymore! That is a good thing.

ThumperMX113 · 12-24-2007, 11:48 AM

This damn website is going to cost me a lot of money ..