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Hi .. after numerous tries ..i found the simplest and cheapest and so far most reliable
the shinney puck from canadian tire....$3.99 lol
not as smooth as the orange ones... but lasts the longest
also honda civic coil packs installed..rotated 180 deg. minor mod to connection .. but works...
 

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20 Posts
Hi .. after numerous tries ..i found the simplest and cheapest and so far most reliable
the shinney puck from canadian tire....$3.99 lol
not as smooth as the orange ones... but lasts the longest
also honda civic coil packs installed..rotated 180 deg. minor mod to connection .. but works...
couple more pics..
and the hockey puck is exact same size as lower stock motor mount I.D.
 

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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...I have a little vibration while idling but nothing I cant deal...
Yeah, I tried shim in earlier iteration of the MCU mod. Too much vibration. Lately I haven't been too happy with my MCU mount. I bought a new insert some time ago and did a simple, straight-forward trim and insert aluminum boss job (no shimming, no drilling-out hole, etc.). It seemed good at the start, but lately it seems like there's extra slop in it, like maybe the material has broken down a bit and allows more play. I'll have to take a look at it at some point. I think it's worse than a new stock mount, now...
 

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Interesting thread. I used to teach undergraduate engineers the basics of both vibration generation in rotating machines and of vibration isolation, so although I've never designed an engine mount I do understand the theory.

The general principal with vibration isolation is to minimise both the stiffness and the damping of the mounts. The latter may seem counterintuitive, and many of my students forgot this by the time they sat their exams, but damping increases the force transmitted through the isolator, making vibration worse. The perfect example of this concept is the old fashioned gramophone record player where the "deck" is suspended on very soft springs and with no damping deliberately added, but it must be screwed down for transit or it will bounce about wildly and could be damaged. Not a particularly useful example for most 20 year olds, but I'm sure there's a few here old enough to know what I'm talking about :)

This low stiffness / high compliance suspension of the deck gives it a low resonant frequency and that is what is needed to achieve isolation of vibration. If you increase the stiffness you increase the resonant frequency, bringing it closer to the vibration frequency you want to isolate. If these frequencies get too close, then instead of isolating the vibration it will start to be amplified! This is why problems can disappear as revs rise above idle and the vibration frequency moves further away from resonance. The other factor in determining resonant frequency is mass. Less mass will increase the frequency so, for the same bits thrashing around inside the engine (pistons and con rods mainly), a nice light aluminium engine will be worse than a heavier lump of cast iron.

As with many things, these general principals only tell part of the story, and an engine has to have its movement limited so it doesn't hit the underside of the bonnet/hood, the bulkhead/firewall, etc and doesn't lurch about too much as you open and close the throttle or shift sideways when cornering, so the design has to be a compromise and a lot of effort goes into designing mounts so their properties match the situation. This may include making their stiffness different in different directions, taking into account the vibration modes the engine will produce, and also making their stiffness change with displacement. You can see this very clearly in the Insight engine mount design where they allow the engine to move a few mm quite easily, but become much stiffer as the gaps in the rubber close up (and even if they tear the engine wont fall out - this type of failsafe design can be even more important in things like steering rack mountings!)
 
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