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Discussion Starter · #1 ·
I've been testing a fix I did to my rear motor mount since Nov 2014 and it is still working very well. So why wait so long to talk about it?

I wanted to make sure the caulking I used wasn't going to fall out of the mount. I also noticed that the 900 rpm idling vibration was slowly being reduced over the time of about a month. I assume that the caulking was partially separating from the original flexible part of the motor mount but not enough to be loose or fall out. I also made a small but critical change in the caulking after analyzing what was going on in regard to NVH.

I have moved my website to a new domain and host and I thought now would be a good time to present my findings to entice people to change their bookmarks when they go to the read the article at my new new olrowdy.com domain.

The caulking I used is Silicone. I also present why I think the fixes so far sometimes have way too much NVH and what I did to try to correct that. Basically the resonant frequency of the whole motor mount assembly was changed too much with the caulks as used so far.

Overall NVH vibration etc is non existent with my modified mount as long as the engine RPM is above resonant frequency the floor of the car. That frequency seems to occur at 900 rpm or less when you stuff the mount with caulking.

I reset my idle to 1000 rpm and there is no vibration off idle and very little with the A/C running at an idle now. Normally I don't run the A/C in the ON mode anyway.
 

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I see that you are using just plain Silicone caulk?

I know many people in the import performance world will use 3M "window weld." I don't know how it stacks up to your silicone...but I do know the window weld has taking a beating from various people and it has help up.

I am going to be using the window weld for my rear mount.
 

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I see that you are using just plain Silicone caulk?

I am going to be using the window weld for my rear mount.
The whole reason for this thread is for others to benefit.

Your window weld approach has been attempted many times here before with lackluster to poor results time and time again.

Olrowdy is trying to spare your time and disappointment from yet another failed “window weld” attempt.

If you to ahead with the “window weld” approach please report back your findings here.

Also if you try the silicone route please let us know your result. Also please be aware with the silicone route it might require alittle break in time before you achieve desired results.
 

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Discussion Starter · #7 ·
I see that you are using just plain Silicone caulk?

There's lots of "plain" Silicone out there. I used Home Depot GE 100% Silicone caulk. I can't speak for how other Silicone based caulking might work.

I know many people in the import performance world will use 3M "window weld." I don't know how it stacks up to your silicone...but I do know the window weld has taking a beating from various people and it has help up.

The motor mounts on these Insights are more complicated than appears on a casual glance. Their reasoning for using Urethane is much different than what Honda used to design the rear motor mount for the Insight.

I am going to be using the window weld for my rear mount.
You want to match the resonance of a medium hard rubber like mount with lots of air gaps. "Super Fast Urethane" doesn't sound like the best choice to do that.
 

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Discussion Starter · #9 ·
How about the old hockey puck trick..
3" dia. fits in snugly. drill through..
takes 1/2 hour and $3.00..
How does it work compared to the rear shock mount that eq1 used? It works great. See this link.
 

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How about the old hockey puck trick.. 3" dia. fits in snugly. drill through.. takes 1/2 hour and $3.00..
Haven't seen that one. What are those pucks made out of? One looks like rubber (=meh), but the other, light colored one?? And what's that fibrous-looking stuff?

I like that $3 price, but whether these work well enough (for me) depends on the material...

At the moment, with my MCU inserts, I'm a little peaved because they need to be re-lubed - hopefully only on the outside flanges. They're making a lot of noise right now, rubbing on the 'fork' thing. It's really amazing how much noise gets transmitted up through the floor with just a tiny tiny amount of rubbing...
 

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Haven't seen that one. What are those pucks made out of? One looks like rubber (=meh), but the other, light colored one?? And what's that fibrous-looking stuff?

I like that $3 price, but whether these work well enough (for me) depends on the material...

At the moment, with my MCU inserts, I'm a little peaved because they need to be re-lubed - hopefully only on the outside flanges. They're making a lot of noise right now, rubbing on the 'fork' thing. It's really amazing how much noise gets transmitted up through the floor with just a tiny tiny amount of rubbing...
Hi.. I was sort of joking about this.
Im working on a "fixer upper" so quickly needed something to replace the badly torn rubber mount.
Hockey pucks come in different materials for different usages.. some very soft.
i used standard hard rubber.. for the time being just to get this thing going.
I thought the very soft orange practice pucks were to soft.
But yes could take some experimenting.
My lower mount comes of very easy..no exhaust hindrance
 

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^ Ha, your joke got me searching online for hockey pucks... I see that most of them are solid rubber, probably not the best of materials/morphology for the rear mount insert... But, I could see how it'd work in a pinch. Plus, you can buy dozens for cheap, so I could see someone actually experimenting with different configs, they might get lucky...
 

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^ Ha, your joke got me searching online for hockey pucks... I see that most of them are solid rubber, probably not the best of materials/morphology for the rear mount insert... But, I could see how it'd work in a pinch. Plus, you can buy dozens for cheap, so I could see someone actually experimenting with different configs, they might get lucky...
Yes..the orange ones are like a semi hard sponge material ( practice pucks)..mabey layers of different grade materials?
kinda like 3d printing but with layers and glue.
I will go back to it later in better weather
I simply dont have an "expensive account" so must make do..:)
 

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^ Check out that link olrowdy posted - the MCU bumpstops fashioned into mount inserts works pretty well. They're like ~$40, probably worth it over buying a new OEM mount, I think they work better than OEMs and will probably last longer... But, I'm still not happy with the overall engine mount experience. Something needs to be done at the front. At some point, maybe, I'll try something like sigma did, with an extra brace at the front.
 

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^ Check out that link olrowdy posted - the MCU bumpstops fashioned into mount inserts works pretty well. They're like ~$40, probably worth it over buying a new OEM mount, I think they work better than OEMs and will probably last longer... But, I'm still not happy with the overall engine mount experience. Something needs to be done at the front. At some point, maybe, I'll try something like sigma did, with an extra brace at the front.
What about a damper type cylinder at the bottom mount...?
isnt it all longitudinal forces there right ..?
its not weight supporting..?
 

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Yeah, don't know about a damper, it's been mentioned before. But the damper itself would still have to be attached to the body or whatever, chassis, so those attachment points would also need isolation...

Rear mount doesn't support weight, it's mostly the translation of the engine/trans rotational forces into kind of up and down, forward and back motion, with a little bit of side-to-side twist. All the mounts have to work together, so it'd be difficult to dial-in a damper type unit that'd work precisely with the fronts. I don't know, having worked quite a bit with the MCU rear thing, my conclusion was something like there's simply too much movement allowed with the fronts. If you make the rear rigid, for example, the fronts still slop around, and, of course, all that movement turns into NVH at the rear, which goes right through the floor at your feet...

I wanted to try MCU material at the fronts, but those are quite a bit more complex than the rear; for example, the center boss/hole isn't centered, you have to compensate for the weight of the engine/trans and how much the inserts will compress under the weight of the engine; they're not the same left and right; etc etc. That was another conclusion I came to - that the project was too complex for me to deal with. You need some serious mathematical/physics chops, not something I have at my finger tips...
 

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Yeah, don't know about a damper, it's been mentioned before. But the damper itself would still have to be attached to the body or whatever, chassis, so those attachment points would also need isolation...

Rear mount doesn't support weight, it's mostly the translation of the engine/trans rotational forces into kind of up and down, forward and back motion, with a little bit of side-to-side twist. All the mounts have to work together, so it'd be difficult to dial-in a damper type unit that'd work precisely with the fronts. I don't know, having worked quite a bit with the MCU rear thing, my conclusion was something like there's simply too much movement allowed with the fronts. If you make the rear rigid, for example, the fronts still slop around, and, of course, all that movement turns into NVH at the rear, which goes right through the floor at your feet...

I wanted to try MCU material at the fronts, but those are quite a bit more complex than the rear; for example, the center boss/hole isn't centered, you have to compensate for the weight of the engine/trans and how much the inserts will compress under the weight of the engine; they're not the same left and right; etc etc. That was another conclusion I came to - that the project was too complex for me to deal with. You need some serious mathematical/physics chops, not something I have at my finger tips...
Yes you are right...
btw whats MCU and NVH?
 

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MCU is 'micro-cellular urethane', or sometimes 'multi-cellular', it's like a foamy polyurethane, pretty dense, springy, quite strong material. I think it's used on most modern cars for suspension isolation parts - like bump stops, especially jeeps and high-end luxury vehicles (I think I read that part somewhere).

NVH=noise, vibration, and harshness

Here's an image of the MCU rear mount insert, from that thread olrowdy posted link:
 

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MCU is 'micro-cellular urethane', or sometimes 'multi-cellular', it's like a foamy polyurethane, pretty dense, springy, quite strong material. I think it's used on most modern cars for suspension isolation parts - like bump stops, especially jeeps and high-end luxury vehicles (I think I read that part somewhere).

NVH=noise, vibration, and harshness

Here's an image of the MCU rear mount insert, from that thread olrowdy posted link:
OK thanks..
yes.. i guess buzzy little unbalanced engine..
Very cool little cars though..
 

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I just completed the motor mount mod using the MCU foam bump stops. I noticed that there was a little bit of extra room in the mount so I made a shim with old oil jugs to take up the extra space and preload the foam a little bit. The oil jug trick was actually a GM suggested fix for strut mounts that had play on the top end 20ish years ago. I have a little vibration while idling but nothing I cant deal. Definitely rides better than the old mount and is lots cheaper than a new mount from Honda.
 
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