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I was tempted to make a steel sleeve with 2 short mounting bolts and reduce the weight of the black tuning blob....
The "black tuning blob" - is that what that is? I thought so myself, but then I experimented with removing it and felt/heard no difference. That side of the bolt is right next to the exhaust pipe - would it be possible the 'blob' is there for heat-sink purposes of some kind? I wouldn't think so, but... If it's not there maybe the bolt and aluminum boss might get too hot, make the rubber brittle eventually? With it there, it absorbs heat and dissipates it, kind of like a buffer, so that the other stuff doesn't get as hot?? Again, I doubt it, but... I think Honda used that huge, heavy metal bracket by the VTEC/'spool' valve for heat sink purposes (the spool valve or whatever gets pretty hot)...
 

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The "black tuning blob" - is that what that is?

The proper name for it is a "bob weight". They are commonly used when balancing crankshafts etc to take the place of the connecting rods, pistons etc. In the good ol' daze it cost $25 to have a Ford V-8 engine balanced.

I thought so myself, but then I experimented with removing it and felt/heard no difference. That side of the bolt is right next to the exhaust pipe - would it be possible the 'blob' is there for heat-sink purposes of some kind? I wouldn't think so, but... If it's not there maybe the bolt and aluminum boss might get too hot, make the rubber brittle eventually? With it there, it absorbs heat and dissipates it, kind of like a buffer, so that the other stuff doesn't get as hot??

If the rear mount weight was used as a heat sink why make it black and out of cast iron? A thin metal shield between the exhaust pipe and the rubber would be a much better solution.

Again, I doubt it, but... I think Honda used that huge, heavy metal bracket by the VTEC/'spool' valve for heat sink purposes (the spool valve or whatever gets pretty hot)...
When I first did my Silicone fix on the rear motor mount I looked at the other two mounts and I seem to remember they also have different shaped tuning weights on them.

Honda must have thought it important to try whatever might help to reduce the vibration of a 3 cylinder motor while idling to go to the trouble of having the strange OEM rear mount. The designers must have seen some improvement by adding bob weights to the mounts.

With my silicone rear mount mod I just raised the idle speed a 100 RPM or so to smooth out the idle vibrations. The remaining vibrations of my fix actually got less and less over a few weeks time. But I now consider my "fix" a short term (several years) fix and really won't recommend it now. I will change my website article to recommend that people come to this thread for a quicker and better way to fix the rear motor mount.

My bob weight is stamped with "MT". So I assume the CVT Insights have a different weight device. My idle speed is still a little higher than stock but I always allow the car to auto stop so I'll probably just leave it as is.
 

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Any photos to show?
Moon car
I took a few pictures but I haven't had a chance to even get them out of the camera because of other projects.

If you don't have a lathe and/or a drill press they won't particularly help over the pictures that eq1 presented.
 

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How is this mod holding up? I was planning on swapping my engine mount for this soon. What kind of lubricant works for the outside of the MCU pieces to prevent the squeaking you described?
 

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Seems to be holding up fine. I took it apart and inspected after a few months and it looked fine. Haven't done that since, though, but it feels fine and looks OK to the casual peek...

I think I used a silicone-based grease on the outside of the flanges, like Silglyde or Superlube. Probably doesn't matter much.
 

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I got a PM that I thought I should copy over here and answer here, in case others ever have the same or similar question:
I have read through your details on doing the rear motor mount rebuild with the bump stops. I noticed that you initially shimmed it in the housing to take up slack, but decided that the shimming was not ideal at idle for vibration transmission. I am currently planning to do this setup, and I was planning to make my own custom housing instead of reusing the aluminum one. If you were to recommend downsizing the diameter of the current housing by any amount, how much would you recommend I take off? Per your recommendations, it appears as though maybe 1 mm or 2 might be appropriate in overall diameter. That would be 0.5 mm or 1 mm difference on each side. Is this a good idea to attempt, or should I just stick with the stock diameter?
I thought I was understanding what you want to do, until I got to the last line: "That would be 0.5mm or 1mm difference on each side." Not understanding where "sides" come into play. Aren't you just asking whether your homemade housing diameter should be a little smaller than the OEM housing? If so, I'd say you could probably make it 1mm smaller and use the MCU inserts as they come, without idle vibration penalty and perhaps with a tad less slack-feel under load. But, it's pretty hard to say...

Basically, the tighter the insert outer diameter fits the housing, the more likely it is you'll need to bore-out the hole through which the spacer/boss fits. Idle vibration can be accommodated either by slack between the insert outer diameter and the housing, or by, not necessarily 'slack', but rather a looser fit of the boss/spacer in the insert. As-is the fit of the spacer/boss in the insert is super tight, so tight that it makes the outer diameter of the inserts expand. That tight fit also makes the MCU a bit stiffer... I guess I don't really have a solid answer for you.

If I were to make my own housing I'd probably make the hole 1mm smaller in diameter than the stock one - because I don't think it'd cause more idle vibration, yet it might reduce slack-feel under load a little bit. If it ended up causing untoward idle vibration I'd just slightly bore-out the hole through which the center boss/spacer fits.
 

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I finally got around to putting this on my car. It worked really well for the first day but then vibration seemed to come back (still better than my almost completely torn through OEM mount). I think I didn't cut enough off of the MCU pieces so they are too compressed between the forks, aluminium washers I made, and the engine mount. I tried wiggling it around and it seems the mount is always contacting the MCU pieces even with no strain which sounds different from your experience.
Bonus - I need to take it apart anyway because I had two washers left over after finishing the installation, d'oh.
 

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hmm, if it worked the first day seems like it should continue to work - unless you got the same vibration noise I got where I had to lube the outside of the insert flanges. As I recall they were rubbing/vibrating on the 'forks' and the noise gets amplified while vibrating the floor. EDIT: Actually, it was the inside of the flanges - basically any part that touches the aluminum housing, though most of the rubbing/noise was from the flanges.

If you didn't cut the insert halves short enough? Seems like the two halves might bulge-up in the middle, where they meet, and/or maybe more material equals stiffer. But I have my doubts that that would be the issue - cuz it seems like it'd work or not, not work day 1 and then stop working...

If the outside diameter/barrel of the inserts contacts the inside diameter of the housing, at idle, then yeah, something's wrong. There shouldn't be any contact. Light contact on the sides is fine (inside of flange against housing)...
 

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I may have just been so excited the first day (and it was a short drive) that I missed the signs. I did put some lubricant in the mount so I hope that's not the problem.
This weekend I'll try pulling it all apart and cutting down the inserts more carefully.
Of course, my second trip after I fixed the mount I get the cat efficiency below threshold CEL...
 

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I
I got a PM that I thought I should copy over here and answer here, in case others ever have the same or similar question:


I thought I was understanding what you want to do, until I got to the last line: "That would be 0.5mm or 1mm difference on each side." Not understanding where "sides" come into play. Aren't you just asking whether your homemade housing diameter should be a little smaller than the OEM housing? If so, I'd say you could probably make it 1mm smaller and use the MCU inserts as they come, without idle vibration penalty and perhaps with a tad less slack-feel under load. But, it's pretty hard to say...

Basically, the tighter the insert outer diameter fits the housing, the more likely it is you'll need to bore-out the hole through which the spacer/boss fits. Idle vibration can be accommodated either by slack between the insert outer diameter and the housing, or by, not necessarily 'slack', but rather a looser fit of the boss/spacer in the insert. As-is the fit of the spacer/boss in the insert is super tight, so tight that it makes the outer diameter of the inserts expand. That tight fit also makes the MCU a bit stiffer... I guess I don't really have a solid answer for you.

If I were to make my own housing I'd probably make the hole 1mm smaller in diameter than the stock one - because I don't think it'd cause more idle vibration, yet it might reduce slack-feel under load a little bit. If it ended up causing untoward idle vibration I'd just slightly bore-out the hole through which the center boss/spacer fits.
Sorry for the confusion. I was thinking that as I increase or decrease diameter, that increase or decrease will be split between the distances on each side of the mount on the inside. So as the diameter were to increase 2mm, the gap on one side of the bushings, if evenly placed, would increase 1mm, since the increase would be split between both sides of the bushing. Not sure if that makes more sense.

Either way, thanks for the help. I am going to try downsizing the diameter of the current housing by 1mm. If things work out well, I will add to this thread with my custom mount findings.
 

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^ OK, that's kind of what I thought you might be saying... So, why do you want to try to fabricate a whole new mount/housing? Seems like a lot of trouble...
 

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^ OK, that's kind of what I thought you might be saying... So, why do you want to try to fabricate a whole new mount/housing? Seems like a lot of trouble...
Well, I wanted to try printing it, as I have the tools to do so. It is more of an experiment. If things don't work out well, then I can switch back to the aluminum housing. I am planning to use a nylon material with chopped carbon fiber reinforcement.
 

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So I have finished printing the mount and pressing the rubber inserts onto the aluminum tube and into the housing. The printing process went well. This is not an exact match the original housing. I removed the aluminum flange on the front of the mount, and I made the hole a little smaller on the bottom that the bolt passes through as to increase the strength of my plastic part. I have included some pictures below. I was going to post the part file of the housing for anyone that wants it, but I can't seem to upload an STL or a STEP file. Does anyone have any recommendations?

However, I noticed that the I don't feel like I have any "looseness" or play between the housing and my inserts. I only decreased the inner housing diameter by 1mm, so I'm not quite sure what happened to all the play. With that said, is that normal for the amount that these inserts are expanded out by the aluminum tubing? It was almost impossible to get those inserts onto the center aluminum tube. The difference in diameter was quite substantial. Since they are so tight, do I still need to put washers on the outside of the inserts to keep them from vibrating off?

I have yet to install the unit on the car (not sure when this will be with my busy school schedule), but I hope to get to it tomorrow. I'll report back on what I feel from the test.
 

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That's pretty cool, interesting. I wonder if it will hold up... What material did you use, and is it solid?

....I noticed that I don't feel like I have any "looseness" or play between the housing and my inserts. I only decreased the inner housing diameter by 1mm, so I'm not quite sure what happened to all the play. With that said, is that normal for the amount that these inserts are expanded out by the aluminum tubing?
I would have expected at least a mm of play between insert and housing. But, it's possible the tolerance for the bumpstops aren't all that precise - I saw a slight difference in diameter between one half and the other with a set of inserts I have.

It was almost impossible to get those inserts onto the center aluminum tube. The difference in diameter was quite substantial. Since they are so tight, do I still need to put washers on the outside of the inserts to keep them from vibrating off?
It's pretty difficult, tight getting the inserts on the 'tube'. I used some cable pull lubricant, the stuff you put on house wiring to pull through conduit. As I recall, once you work it in there a few times it gets easier... The inserts do expand quite a bit, a few mm as I recall, from the tightness. If your inserts are too tight in the housing, you can bore-out the center hole a little so the 'tube' isn't so tight, and then the insert won't expand as much. But, it can be a bit sloppy boring out that hole, so I'd prefer not to do that. I did do that, but then I ended up putting duct tape around the 'tube' to make it tighter again...

I think I would put washers/spacers on the sides. You want the inserts to remain centered in the housing, not shifting to one side. The spacers prevent that shifting. Regardless of the tight fit I think it would probably shift, if not permanently, it might on load, and you don't want that. But, you could try it without spacers, find out if it really matters...

Are your inserts tight against the housing in the middle or just at the edges/ends? The flanges of the inserts are curved, i.e. where they butt-up against the housing that's curved, like a ramp, so depending on how much you trimmed the insert length that curved portion could be tighter against the housing, yet the middle won't be. The way I have it setup, that curved portion just grazes the housing, yet the middle section doesn't touch the housing.
 

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That's pretty cool, interesting. I wonder if it will hold up... What material did you use, and is it solid?



I would have expected at least a mm of play between insert and housing. But, it's possible the tolerance for the bumpstops aren't all that precise - I saw a slight difference in diameter between one half and the other with a set of inserts I have.



It's pretty difficult, tight getting the inserts on the 'tube'. I used some cable pull lubricant, the stuff you put on house wiring to pull through conduit. As I recall, once you work it in there a few times it gets easier... The inserts do expand quite a bit, a few mm as I recall, from the tightness. If your inserts are too tight in the housing, you can bore-out the center hole a little so the 'tube' isn't so tight, and then the insert won't expand as much. But, it can be a bit sloppy boring out that hole, so I'd prefer not to do that. I did do that, but then I ended up putting duct tape around the 'tube' to make it tighter again...

I think I would put washers/spacers on the sides. You want the inserts to remain centered in the housing, not shifting to one side. The spacers prevent that shifting. Regardless of the tight fit I think it would probably shift, if not permanently, it might on load, and you don't want that. But, you could try it without spacers, find out if it really matters...

Are your inserts tight against the housing in the middle or just at the edges/ends? The flanges of the inserts are curved, i.e. where they butt-up against the housing that's curved, like a ramp, so depending on how much you trimmed the insert length that curved portion could be tighter against the housing, yet the middle won't be. The way I have it setup, that curved portion just grazes the housing, yet the middle section doesn't touch the housing.
I used a material filament called NylonX. It is a nylon base with about 20% chopped carbon fiber reinforcement, if I remember correctly. I have gained experience using a printer made by Markforged called the Marktwo. It prints with a similar type of material, but it is capable of placing continuous strands of carbon fiber in the part for incredible strength properties. I don't have access to it for my personal projects, but my home printer can print the NylonX, which is the next best thing. If anyone is planning to attempt this, I can let you know what settings I ran on my setup. The part is technically 80% dense with a triangular infill pattern for strength. I ran 4 continuous wall layers. I have attached a picture for better visualization.

As for the tightness of the inserts, I just used WD-40 to get it on with a vice and my whole body weight. I don't know which one it is butting up against. My guess is that it is the filleted edges on the sides that it is touching, but I can't be sure. The insert can be rotated within the housing, so it isn't overly tight, but I can't get any play in any other direction. I'd imagine this will give me plenty of vibration at idle, but I will have to see. If I do, I'll try to back those off so the lips on the edge aren't contacting the sides of the housing too heavily. I'll probably print the spacers/washers before I go for a trial run. Any recommendations for the OD of the spacers/washers?
 

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^ Great image...

....If anyone is planning to attempt this, I can let you know what settings I ran on my setup. The part is technically 80% dense with a triangular infill pattern for strength...
If you find that it holds up I might try it in the future. I'm thinking the plastic and being less than solid might provide better 'noise reduction' properties than a solid hunk of aluminum...

As for the tightness of the inserts, I just used WD-40 to get it on with a vice and my whole body weight.
That sounds like a lot more effort than it took me. I wonder if there's a difference with your inserts... Also, WD-40 might not be the best lube, as it will probably stay greasy. I think ideally you'd want to use something that evaporates, doesn't leave a residue, so the inserts don't rotate on the 'tube'... I don't know, maybe it doesn't matter. I drilled some holes in mine, through the sides, so I didn't want the inserts to rotate. But they do, a little...

I'll probably print the spacers/washers before I go for a trial run. Any recommendations for the OD of the spacers/washers?
Not off the top of my head, but here's an image of my mount when I tried using steel washers, and that diameter was fine. I ultimately used plastic washers, I think I cut some 1/8" PVC sheeting I had on hand, or maybe some polyethelene... Actually, looking at this image now, I can see the washers don't have to have as big a diameter as these have...

83633


And fyi, here's an image of when I tried using a rubber shim between insert and housing. The shim is made from an old rubber Honda Fit floor mat, so that gives you an idea of how much slack I had between insert and housing:
83634
 

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^ Great image...



If you find that it holds up I might try it in the future. I'm thinking the plastic and being less than solid might provide better 'noise reduction' properties than a solid hunk of aluminum...



That sounds like a lot more effort than it took me. I wonder if there's a difference with your inserts... Also, WD-40 might not be the best lube, as it will probably stay greasy. I think ideally you'd want to use something that evaporates, doesn't leave a residue, so the inserts don't rotate on the 'tube'... I don't know, maybe it doesn't matter. I drilled some holes in mine, through the sides, so I didn't want the inserts to rotate. But they do, a little...



Not off the top of my head, but here's an image of my mount when I tried using steel washers, and that diameter was fine. I ultimately used plastic washers, I think I cut some 1/8" PVC sheeting I had on hand, or maybe some polyethelene... Actually, looking at this image now, I can see the washers don't have to have as big a diameter as these have...

View attachment 83633

And fyi, here's an image of when I tried using a rubber shim between insert and housing. The shim is made from an old rubber Honda Fit floor mat, so that gives you an idea of how much slack I had between insert and housing:
View attachment 83634
My goodness! I most certainly don't have that clearance. I am starting to wonder if we used the same bump stops or not? Mine were Belltech 4925 Bump Stop Kit. I grabbed it off of Amazon. Considering the huge clearance difference we are dealing with, I imagine I will be getting some large vibrations. If not, then I will just stick with it. I will print some spacers at around an 1/8" thick with an OD of around 1.5-2" to see how it goes.
 

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Great work. To answer your question about posting you math files, the secret is to rename the file something the system will accept like .txt.
 

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My goodness! I most certainly don't have that clearance. I am starting to wonder if we used the same bump stops or not? Mine were Belltech 4925 Bump Stop Kit.
Same brand/part number as what I used. Reading my older posts, I wrote that the gap between inserts and housing was 3mm. If convenient, you should take an actual measurement of the housing hole in your OEM mount and your new DIY mount, and outside diameter of your inserts with the 'tube' inserted, post back so we know why you have a potential clearance issue...

Considering the huge clearance difference we are dealing with, I imagine I will be getting some large vibrations. If not, then I will just stick with it.
You might. But like I said, you can bore the tube hole to compensate. I'd try what you have first though. It's not difficult to install the mount - I must have done it at least a dozen times when I was dialing-in this mod...

I will print some spacers at around an 1/8" thick with an OD of around 1.5-2" to see how it goes.
Just measure how much 'tube' you have sticking out beyond the inserts and add about 1mm - that's the thickness for the washers.
 
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