Another little update for those who are still following this...

I finished the jig. Once done I see that there is not quite enough material removed from the center 'post' of the mount.



I will probably be hogging off some with the mill once I get the piece secured in the rotary table. If I can secure the base I will be removing more from the inner wall as near to the outer metal sleeve as I can.

Some of the articles have suggested burning off the rubber, but this is ecologically unsound.

There are factory rivets in the mounts that were used to fill them with fluid. I will probably just drill them out and tape them over before pouring the polyurethane.

 

Wow, nice work!
Are these your worn SRT mounts in the jig?

 

Yep, those are my original factory mounts. Driver side was broken. The ones that were sent to me are in the vehicle now and are holding just fine.

I will be passing them on when this project is complete... in my copious amounts of spare time.

 

watching with interest.....updates?

In relation to getting a little more clearance for Vadim headers...it was stated here...
https://www.crossfireforum.org/forum...tml#post699443
that you went for taller mounts....

....I've since undestood you simply used those taller mounts (3/8") from 996Krazy (from TAFKA...32Krazy) as temporary ones and are refitting your poly jobs as soon as they cure.
I havent determined why the mounts were 3/8" taller as I don't think a descriptor or PN# is mentioned.

-------------------
Had a look over at Autohaus at the Lemfoerder's but they want $94 each...+ ship
https://www.autohausaz.com/search/pr...ine/MotorMount

Might have to do some more looking. I'm due for a box of goodies from autohausAZ and was updating my order to get the mounts thrown in - but at $190 for 2...hmmm

 

Billy22bob,

I've been really busy with family and work. No time to hog out that extra rubber. The temporary mounts that are in are holding up fine for now.

I'll try and get them done this week if possible.

Cheers!

 

Sorry - I never noticed this thread or I would have responded earlier. I am the one that sent Steve the motor mounts. I am glad to see they found another home and are being put to good use.

They are from an SLK32 and while they maybe heavy they had virtually no integrity left. You could rock the motor my hand.

Happy to chime in with any answers I can provide.

 

Wow, that's amazing. I could not get the motor to shift much at all. BUT, that makes them a good candidate for later fill. So far they are holding up a lot better than my broken mount. LoL

Again, I will try and get further along this weekend.

Cheers!

 

Interesting - I'm going to put the VRP headers on and since I gotta undo the motor mounts..I figured - why not change 'em out - poly or no poly.

Someone also mentioned - "maybe I should go with the "taller mounts" MMZ went with - that since turned out to be ...what SRT6 is saying are stock SLK32 mounts....and shot ones to boot....

so .....that infers the SRT6 mounts that MMZ took out from his SRT6 may be slightly different (3/8" lower) than the SLK32 "temporary" ones he put in from SRT6_Roadster (via 32_Krazy).

So,
I'd like to put a down payment on the stock mounts...autohaus are a little pricey but I've already assembled an order of other stuff and post may not be that much more....however before I make the call...any other ones cheaper than $100each shipped to Australia? I thought MMZ indicated $37 ea or soemthing from somewhere (but possibly cheap imitations according to some). They said stick with autohaus or parts.com

 

Haven't had hands on experience with the motor mounts.. but could a 1/4" to 1/2" plate be used to shim them for a little extra clearance?

 

LOL - That is just crazy. In the SLK they shifted like a ****. I would go with they position that they had more life than I was lead to believe but I saw them move around like crazy.

That said I am glad they are working for you. I filled new mounts with poly which was a nice improvement but did cost $$$.

 

Okay everyone, here is the progress from last Saturday and this Saturday. Second jig and hogging out of the excess rubber from both mounts is complete and the pour has been completed. Just waiting on initial set up and then it's one week before 100% cure.

On to the pictures! Here I used a four flute end mill to drill out two holes so I could drain off the fluid.


This is how much fluid I drained out of the passenger side (right side) mount which was still in good shape.


Next you can see the center removed after cutting with the mill on a small rotary table. I was able to pry it out after cutting most of the way through.


The base of the mount hogged out and cleaned up. You MUST de-grease all the parts and let them dry completely before pouring the Polyurethane!!! If you don't it can contaminate the Polyurethane and cause it to weaken or not even cure properly.


After trimming, de-greasing, drying and set up in the jig, the mounts are ready to pour. Here they are next to the 80A Polyurethane. Make sure your jig/mounts are absolutely level before beginning your mix or pour. This will keep them nice and level with the top edge and they will come out very nice.


The can WILL be over half empty. This allows proper mixing without spillage. Make sure and shake the activator (part B) before pouring into the base (part A). Stir thoroughly for at least TWO (2) minutes. A bit longer is fine, but your working time is only 15-25 minutes at 77°F (25°C), so try to stop between two and three minutes and begin the pour.


Before that 15-25 minutes is up, you have plenty of time to pour very carefully and slowly so as to fill the voids and allow the air to bubble out properly. Here are mine within that first 15 minutes. Done, level and not too shabby. If you see the air bubbling out and the level dropping, you can continue to top off the mounts within that 15-25 minutes. I think I had more time as it was only about 70°F (21°C).

 

Im gonna be doing this. Nice write up.

 

It will be interesting to see what others have done without the rotary table and jig....many have gone before without these tools.
I - like others will be doing by hand - the jig is a nice touch though.

You can see why the mount fails when they were originally designed for a stock SLK320 and we have 60% more hp/tq - but they (MB/AMG) dont seem to have upgraded the mounts to compensate.

Thanks for the write up.
We look forward to your comments on the performance.

I'm still thinking a strut tower brace and little shock/damper would assist the longevity of a stock mount similarly - but that might be new teritory by the soundz.
Plan A - New Mounts coming in order from AutohausAZ along with TM Mount, TM conductor plate (looking forward to this), rear pads, rocker cover and inlet/exhaust gaskets, sump sealant, EGR NRV...etc..etc...
So I'll have my used mounts out in a few weeks.

Link for the purchase of the 80A Poly?

 

Here you go... McMaster-Carr Hard 80A Polyurethane - Product # 8644K11

Edit: If you are going to do this by hand, I recommend using a large vise at the very least to secure the mount while drilling. Brace yourself and your drill to go through the rubber around the center like my mill and use a 1/4" to 3/8" bit. You can make multiple holes around the perimeter of the center portion of the mount and then cut the remaining rubber with a VERY sharp wood chisel and hammer. Also, trimming out the excess rubber from the outer housing with a sharp wood chisel is preferred to trying to cut with a box or utility knife. This would be about the safest route I can think of. I trimmed up the center piece with a utility knife but the piece was held firmly in a large vice for safety. Don't forget unbroken mounts are full of about a cup of fluid, if you want to drain them first, drill only two holes to start like I did. (One for drain, one for air.)

Whomever wants the mounts, and jigs for their project need only pipe up and/or PM me. I will be putting these back in next week. Cheers!

 

I would love to try this, please put me on the list to use the jigs.

 

Tunaglove I would like to be next if and when you are finished.

 

turnaglove,

Sounds like I need to put together a package for you after tomorrow.

Stay tuned everyone. I'll be giving my impressions after the newly completed mounts are installed.

Wheee!

 

The "New" mounts are in! Whoot!

Here they are prior to install after taking them out of the jig.


Initial impressions are thus:

1. Vibration at idle in park is slightly noticeable.

2. Vibration at idle in gear is VERY noticeable. BUT, I am still running on the factory injectors and they have not been cleaned in about 40,000 miles.

3. Vibration at any RPM above 450 is non-existent. Throttle response in lower gears at any RPM above 1000 is nearly instantaneous.

Overall an excellent upgrade for occasional track time with the caveat that if you do this and want to retain the stock soft idle feel, use the lower 60A durometer polyurethane. This will allow it to absorb more vibration while retaining the strength of filling the whole mount as I have done.

80A vs. 60A vs. 40A:

You may be able to go as low as 40A, but I suspect on the SRT6 they would fail being that soft.

Looks like I will have to look at the rough idle now, which was completely unnoticeable even with the substitute mounts. Possible crank sensor? or fuel injectors? Further investigation is in order.

Questions? Comments?

 

Every single time I've had an unstable idle with my SRT it's been a leak. Usually the gaskets under the manifolds. (mine seem to come off with regularity)
I just replaced the stock metal gaskets with Rob's cork gaskets and all my issues disappeared. I'm not saying that's your issue, just that it could be.

Les

 

I appreciate that velociabstract, I have not yet examined the factory gasket conditions. So these are the intake manifold gaskets? Please elaborate.