Dr.Jeff
True Classic
Overall, looking at the discussions we've had about this mount, several ideas have come up for potential "improvements". It would be nice to gather all those ideas into a revised design that perhaps could be produced in a limited run. A couple ideas that come to mind off hand might be:
1) Using a more durable material for the 'rubber' portion. I'm thinking one of the more compliant duros of urethane would be good. The other thread described some tips for making a mount with this material.
2) With the new filler material used to construct it, we could also eliminate the "voids" (air gaps or openings) like the stock mount has, to lessen any chance of it over compressing/collapsing.
3) Either repositioning the "center pin" to slightly raise the drivetrain, or maybe even come up with a practical means of making it adjustable height (other than slotted holes). Or would using a material that won't sag (#1 above) preclude the need for this?
4) regarding the 'center pin', @Mxgrds made a good point in post #29 above. A larger surface area for the interface between the pin and the filler material will reduce the pin's tendency to dig into it. However I've noticed most of the mounts I've had include a 'bushing' around the center pin that increases it's OD considerably. Although sometimes it isn't apparent that bushing is there until you begin to deconstruct the whole thing; often the rubber is cast over the edge of it so it cannot be seen. But maybe something even better can be done. In the prior thread we discussed adding extension "arms" to the center pin, going further out into the filler material to achieve this. That will also improve the adhesion of the urethane to the metal components.
5) The concept of a torque arm added to the lower mounting of the trans has been found beneficial in preventing trans damage. So why not incorporate the ability to add one into the revised lower mount design. Such as adding a tab to one end, similar to what @GregS showed in post #35. I'm thinking something shaped into the flat plate of the mount, akin to the exhaust hanger extension arm on some stock mounts (but much shorter). Then the user can decide to easily add the torque arm if desired.
6) Does it need any further support to prevent 'twisting' from side to side (e.g. added stability)? I'm thinking of the idea of side reinforcement plates that was brought up in the prior thread (reference link is needed here).
7) #6 brings up a related question I think we previously addressed to some extent; the ability of the drivetrain to 'rotate' about the center pin of this lower mount. The engine moves fore/aft with the torque of acceleration/deceleration, which will "pivot" or rotate around the lower mount. The 'dogbone' is intended to control this, as would adding a torque arm to the lower mount (see #5). But I believe the lower mount is intended to offer some compliance to allow for these 'rocking' movements. With the soft rubber filler material in a stock mount there is plenty of flexibility to allow the pin to twist within the rubber. But with a more firm material (like urethane) there will be less flexibility. So is more allowance for 'pivoting' needed (e.g. a bearing around the center pin)? Or would that just counter the effects of the dogbone and torque arm?
Other thoughts, ideas, suggestions???
1) Using a more durable material for the 'rubber' portion. I'm thinking one of the more compliant duros of urethane would be good. The other thread described some tips for making a mount with this material.
2) With the new filler material used to construct it, we could also eliminate the "voids" (air gaps or openings) like the stock mount has, to lessen any chance of it over compressing/collapsing.
3) Either repositioning the "center pin" to slightly raise the drivetrain, or maybe even come up with a practical means of making it adjustable height (other than slotted holes). Or would using a material that won't sag (#1 above) preclude the need for this?
4) regarding the 'center pin', @Mxgrds made a good point in post #29 above. A larger surface area for the interface between the pin and the filler material will reduce the pin's tendency to dig into it. However I've noticed most of the mounts I've had include a 'bushing' around the center pin that increases it's OD considerably. Although sometimes it isn't apparent that bushing is there until you begin to deconstruct the whole thing; often the rubber is cast over the edge of it so it cannot be seen. But maybe something even better can be done. In the prior thread we discussed adding extension "arms" to the center pin, going further out into the filler material to achieve this. That will also improve the adhesion of the urethane to the metal components.
5) The concept of a torque arm added to the lower mounting of the trans has been found beneficial in preventing trans damage. So why not incorporate the ability to add one into the revised lower mount design. Such as adding a tab to one end, similar to what @GregS showed in post #35. I'm thinking something shaped into the flat plate of the mount, akin to the exhaust hanger extension arm on some stock mounts (but much shorter). Then the user can decide to easily add the torque arm if desired.
6) Does it need any further support to prevent 'twisting' from side to side (e.g. added stability)? I'm thinking of the idea of side reinforcement plates that was brought up in the prior thread (reference link is needed here).
7) #6 brings up a related question I think we previously addressed to some extent; the ability of the drivetrain to 'rotate' about the center pin of this lower mount. The engine moves fore/aft with the torque of acceleration/deceleration, which will "pivot" or rotate around the lower mount. The 'dogbone' is intended to control this, as would adding a torque arm to the lower mount (see #5). But I believe the lower mount is intended to offer some compliance to allow for these 'rocking' movements. With the soft rubber filler material in a stock mount there is plenty of flexibility to allow the pin to twist within the rubber. But with a more firm material (like urethane) there will be less flexibility. So is more allowance for 'pivoting' needed (e.g. a bearing around the center pin)? Or would that just counter the effects of the dogbone and torque arm?
Other thoughts, ideas, suggestions???