Reinforced front motor mount project w/ pics

[speedysprocket]

Inspired by another member here, I decided to take an old mount and make it a little stronger. I removed the limiting pin and drilled the mount in four locations, on the ribs. In an effort to limit NHV, I’m trying these rubber lined washers (stacked x2 on the base and x1 on top) and grade 8 hardware, 5/16”. Loctite will be used once I torque everything down. Let me know what you think! There is always room for improvement. These things seem to fail just as fast as you press the gas pedal down or chirp the tyres.

Basic Design:

Inside view:

NVH "eliminators"

Bye bye limiting bracket and limiting pin:

Still brainstorming for options on keep in the washers intact because of the high pressure and torque. Maybe a little JB weld around them to form a retainer or shroud

 

[rubydist]

that should keep it from pulling apart.

 

[NotSoSlowSHO]

Too bad I see a hardware FAIL.

For those nylon locking nuts to work, the threads of the bolts have to actually be threaded THROUGH the nylon.

Sorry to say, your bolts are coming up short.

 

[speedysprocket]

Too bad I see a hardware FAIL.

For those nylon locking nuts to work, the threads of the bolts have to actually be threaded THROUGH the nylon.

Sorry to say, your bolts are coming up short.

As I mentioned, they are not torqued down. The bolts are long enough for the nylon to grab.

 

[Lorenr]

Looks Good

I did the same thing, except that I did not consider the rubber washers. I did leave the long cross screw in place as a safety measure, but decided against replacing it with a larger one.

I did not use rubber bushings and did not tighten the 3/8 grade 8 screws other than to take up most slack. I only used one screw per side. I reasoned that there should be a little play in the mount.

I completely removed the stock shock absorber system to ease access.

I'm not completely satisfied with the result as there is a good amount of vibration, especially at start up. While cruising on the highway it feels fine but firm. I'm thinking about what to do next but believe we are on the right track.

 

[AREA 91]

I still prefer to use urethaine when I reinforce them.

 

[speedysprocket]

I still prefer to use urethaine when I reinforce them.

I have tried to shim the mount using a limiting pin, but never the urethane method. Seems like a lot of work and mess plus the jig but the finished product does look impressive. The rubberized washers in this case should reduce NVH. They may also be smashed to peices after a few hundred miles. The mount is fully adjustable but I did use red locktite on the stop nuts. Here is the finished product, will install next week.

 

[Whydah91]

I'm sure your rig works. But why not just buy the Shosource urethane built units and be done with it forever? $190 after core buys the one that always breaks, and thats gas money in the world of SHOs.

 

[speedysprocket]

I'm sure your rig works. But why not just buy the Shosource urethane built units and be done with it forever? $190 after core buys the one that always breaks, and thats gas money in the world of SHOs.

Because this one cost me $8 in hardware, plus its fun.

 

[SHO Continental]

I have mine reinforced with only two bolts per mount. Have held up on a few track days and over a year so far.

 

[kevinspann]

Those rubber isolators won't do much for reducing NVH, but oh well. I didn't use any when I did mine.


Are you going to be putting some kind of limiting bar back through the middle?

 

[speedysprocket]

Those rubber isolators won't do much for reducing NVH, but oh well. I didn't use any when I did mine.


Are you going to be putting some kind of limiting bar back through the middle?

No need, I think the current configuration is much stronger than the stock limiting pin. And here is the final product.

 

[SHO87]

Let us know how this turns out. I am in need of some improvement down there and with christmas around the corner my budget just got pushed back further! lol... Will this fix the back aswell? How much of a permanent fix is this? I would like to know if this is a complete waste of time or well worth it. Thanks

 

[kevinspann]

It's as permanent as the bolts are. I did the same for my front and rear mounts.

 

[itwonder]

... why not just buy the Shosource urethane built units and be done with it forever?

Because the urethane makes them really stiff which transmits a lot more noise and vibration than the stock mount. I rebuilt mine with urethane; would not use that method again.

Your repair is fine; has been done before. I'm not sure why you took out the limiting rod - usual practice is to replace it with a larger diameter bolt.

 

[Eric VerValin]

Urethane makes them really stiff if you use stiff urethane. There are multiple grades you know.

 

[speedysprocket]

Because the urethane makes them really stiff which transmits a lot more noise and vibration than the stock mount. I rebuilt mine with urethane; would not use that method again.

Your repair is fine; has been done before. I'm not sure why you took out the limiting rod - usual practice is to replace it with a larger diameter bolt.

Yeah I saw a post here and thats what I based this one on, but with rubber isolators added. Will put something in place as a fail safe for the limiting pin.

 

[SHO87]

How do you know if the mount is salvagable or not?

 

[speedysprocket]

How do you know if the mount is salvagable or not?

Most old mounts, even if broken, can be fixed with this method. Just make sure most of the rubber is intact and you shouldnt have a problem, even if it has pulled apart from the metal.

EDIT: See pics below. The old mount, despite the fact it has completely torn apart, can be re-used without to much work. i just have to glue the mount back together so its intact before the overhaul.

 

[K-Dawg]

Those rubber isolators won't do much for reducing NVH, but oh well.

Agreed.