"Dog-bone" [engine torque strut] rebuild...updated with new content

[Fiataccompli]

thanks for the follow-up. I have a solid piece of metal as the dogbone in my '85. Oddly, I don't mind so much. I picked up some motor mounts to do this to replace the metal (installed by a PO), but haven't done it yet.

 

[lookforjoe]

I hope I can get my X1/9 out soon - we had about 5" of snow today I want to try this rod for comparison. I ordered a few more of the bushings for my other spare rod. These ones I'll drill first to see if it changes the tendency to split in the center.

 

[Dr.Jeff]

By the way, I tried freezing a couple of the rubbers before drilling but really did not notice much difference. The only one I had any trouble with was the first one I drilled. I did not have it anchored to the drill press table (just held it by hand) and tried to drill it too quickly (forced the bit into the rubber), and it grabbed and tore a chunk out. But no splitting, even while installing. So I'm curious if you find any difference by drilling first (that's how I did all of mine).

 

[PaulD]

By the way, I tried freezing a couple of the rubbers before drilling but really did not notice much difference. The only one I had any trouble with was the first one I drilled. I did not have it anchored to the drill press table (just held it by hand) and tried to drill it too quickly (forced the bit into the rubber), and it grabbed and tore a chunk out. But no splitting, even while installing. So I'm curious if you find any difference by drilling first (that's how I did all of mine).

If you are into sharpening drill bits, you can put a steep drilling angle on the front of drill (making it pointier). It will then drill rubber without grabbing.

When I drilled the centers of mine, I had the right size high quality hole saw, and it did a fine job. I drilled well under the size of my oversize sleeve, so when I pressed it in, the rubber expanded to the full width of the dog bone retainer. (I have 1/2 inch bolts on my top engine mount, my solid mount is a turnbuckle type arrangement with heim ends in chrome molly tube. I transmits a lot of vibration so I am experimenting with rubber. I have very a very long intake manifold going into the trunk, so I need to limit the movement of the engine).

Paul Davock

 

[lookforjoe]

I put the dogbone in today (Dr.Jeff revision) - on mine it takes a little fiddling to get it out past the various obstacles -
Volvo-bushed one coming out:

Replacement in -

The change in vibration level was immediate - just starting the engine I could feel the reduction in the transmitted levels of engine vibration. I'm much happier with the damping this bushing provides. The only thing to see is how well the bushings hold up over time. These softer ones, if anything like the Vicks-supplied version, may well split within a few months of constant use (To their credit they did give me a replacement for this at no charge, however the replacement split in just a few hundred miles of use, like the original purchased item).

Vick auto example:

 

[Dr.Jeff]

Great feedback, thanks for reporting. Yes it will be interesting to see how these hold up. However the fact they are a solid rubber design, vs the stock design with large "voids" molded into the rubber, I expect them to have much better longevity.

 

[AKimball92]

I just ordered by bushings yesterday and plan to attempt this later this week. (I had already purchased poly bushings as suggested in one of Dom’s Revtech videos (highly recommended if you haven’t watched them). What he doesn’t show is that he filled the voids with a silicon caulk as those bushings flopped around in the bar. That way seemed harder and less reversible compared to these 4 dollar pucks.

One thing I thought of doing was using a grinder to round off the stamped edge. Little more time, makes installing slightly easier, and hey added lightness (every gram counts).

 

[AKimball92]

In response to drilling, what do you guys think of clamping the bushing under a board with 2 clamps under the press and drilling through the board. Thought not to press hard on the board and to drill initially drill through the hole for visual aid. Nothing should move this way.

 

[Dr.Jeff]

round off the stamped edge

Which edge are you referring to? The rubber bushings I used have square shoulders on both outside edges. Perhaps that is what you are thinking of rounding-off? If so I honestly don't think it will help. They 'squish' enough to go into the metal housing without needing to remove any material. Use some light lube to help maneuver them into position.

clamping the bushing under a board with 2 clamps

That might work well, assuming you can find the center of the bushing to drill out once the board is in place. I kind of did the same thing with a large washer:

It seemed to me that having the bushing well secured to the drill press, and not feeding the bit to quickly, were the biggest helps to prevent damage. Of the four bushings I drilled only the first one had any issues (I did not have it secured and fed the drill heavily).

Please document anything you try and report how it works.

 

[AKimball92]

Which edge are you referring to? The rubber bushings I used have square shoulders on both outside edges. Perhaps that is what you are thinking of rounding-off? If so I honestly don't think it will help. They 'squish' enough to go into the metal housing without needing to remove any material. Use some light lube to help maneuver them into position.

I meant to clean up the metal dog bone with a stone dremel bit. Honestly I doubt it will remove any weight even measurable, more like filing off the sharp edges. But hey, I would like to think this adds an easy 5 hp.

That might work well, assuming you can find the center of the bushing to drill out once the board is in place. I kind of did the same thing with a large washer:

It seemed to me that having the bushing well secured to the drill press, and not feeding the bit to quickly, were the biggest helps to prevent damage. Of the four bushings I drilled only the first one had any issues (I did not have it secured and fed the drill heavily).

Please document anything you try and report how it works.

I will take a many pictures as I can of the process. Drilling the hole first into the block of wood (or your washer) and then ensure the wood and bushing holes line up concentrically as close as I can tell should be plenty fine for this application.

 

[Dr.Jeff]

I meant to clean up the metal dog bone

Ahhh, I misunderstood, thought you were referring to the rubber insert. Cleaning up the metal edges would be good but don't remove the lip itself. It helps keep everything in position, and these bushings end up a little narrower than the stock ones so the metal lip has plenty of clearance.

I think the wood idea will work well. Thanks in advance for letting us know how it goes (I will be doing more rubber drilling for another project).

 

[lookforjoe]

Had to revise mine. Since the engine bracket is offset relative to the body bracket (why???) the soft rubbber bush “walks” inward pretty quickly - within a couple hundred miles.

Left side

Right side

The outer bushing hubs then rub/ knock against the engine and body mount brackets under load - it was obvious when that point arrived.

So, I removed the arm and added spacer sleeves that I drilled to a press fit over the inner side of the metal sleeve. This should prevent the bushing from walking inside the metal bushing hub. I did also cut one of the rubber bushes in half, to use to fill the width gap, but since the load pushes to the inside, that wouldn’t necessarily stop the bushing and hub from walking laterally on the inner sleeve anyway - so I didn't add them.

 

[Dr.Jeff]

If you look back at page one, I wondered if this might happen. No idea why the mounts tend to not align squarely; could be due to the condition of the other mounts, or to weight imbalances, or simply to poor initial engineering. I suspect all three are at play. On mine the old side mount (snail mount) has done the same thing, migrated to one side until there is metal on metal contact.

A suggestion I had on page 1 was similar to yours, placing plastic shims to help keep the rubber centered:

The poly spacers don't need to be this large of OD, its just what I had on hand to play with.

Mine still hasn't been road tested, and won't be for some time, so I don't have any feedback on this issue. Very interested to see how this works for you. Thanks for keeping it updated.

 

[Dr.Jeff]

Thinking a bit more on this. The poly spacers should keep the rubber centered on the inner metal sleeve. However if the rubber now begins to migrate within the outer metal housing (the round end piece), then the 'half' width rubber bushing would be needed to keep things centered again. Well see.

Also, I wonder if the drilled ID within the rubber (when modified to fit the inner sleeve) could be reduced to make the rubber a tighter fit on the sleeve. Although I really doubt it could be made tight enough to prevent all migration.

 

[lookforjoe]

Thinking a bit more on this. The poly spacers should keep the rubber centered on the inner metal sleeve. However if the rubber now begins to migrate within the outer metal housing (the round end piece), then the 'half' width rubber bushing would be needed to keep things centered again. Well see.

Also, I wonder if the drilled ID within the rubber (when modified to fit the inner sleeve) could be reduced to make the rubber a tighter fit on the sleeve. Although I really doubt it could be made tight enough to prevent all migration.

I used 11/16" drill, and (lubed) pressed the sleeve in, so they are very snug. The poly sleeve I used allows plenty of compression space for the bushings - the one you have would be too close to the hub, IMO. I didn't worry about centering the bush, since it loads on the inside I pushed the bush most of the way in to start with this time.

 

[kmead]

Perhaps we are thinking about this problem in the wrong way.

Today many of us have worn rubber bushes in a perfectly good steel mounting. What if we just gave in to the fact what it is not a serviceable part?

Many cars use a “torque strut” to control longitudinal motion of the engine. Could we perhaps find something similar from another car and either get lucky and find one the exact configuration we need (yes even a blind squirrel finds a nut someday) or modify one to the configuration we need?

Toyota and nearly every other manufacturer uses a similar unit to what we have but the ends are at 90° to what we need or they length is wrong but the ends are joined by a simple steel rod or tube. Which suggests that it could be cut and rewelded to make the proper length and clocking.

Or in the blind squirrel category, perhaps we find the right length in one of the many aluminum housing based units

Perhaps some time spent measuring what we have and then wandering a Pickapart would yield a part(s) we can buy new that could serve our purposes? Modern mounts last a good long time under greater loads and we could always buy a spare to have for the future.

Just a thought.

 

[Michael Hunter]

Perhaps we are thinking about this problem in the wrong way.

Today many of us have worn rubber bushes in a perfectly good steel mounting. What if we just gave in to the fact what it is not a serviceable part?

Many cars use a “torque strut” to control longitudinal motion of the engine. Could we perhaps find something similar from another car and either get lucky and find one the exact configuration we need (yes even a blind squirrel finds a nut someday) or modify one to the configuration we need?

Toyota and nearly every other manufacturer uses a similar unit to what we have but the ends are at 90° to what we need or they length is wrong but the ends are joined by a simple steel rod or tube. Which suggests that it could be cut and rewelded to make the proper length and clocking.

View attachment 10876
Or in the blind squirrel category, perhaps we find the right length in one of the many aluminum housing based units

View attachment 10877

Perhaps some time spent measuring what we have and then wandering a Pickapart would yield a part(s) we can buy new that could serve our purposes? Modern mounts last a good long time under greater loads and we could always buy a spare to have for the future.

Just a thought.

Great thoughts....i think that's a very feasible option

 

[AKimball92]

I wonder why modern vehicles have the 90 degree offset? My guess is it frees up a degree of freedom aiding in bushing longevity. Through all the SOHC variants or even other DOHCs perhaps, is there a bracket that mounts off the cam housing but at 90 degrees to the X1/9 bracket. It might be easier to fab a 90 degree bracket to match a Civic mount or something. Or we could suck it up and either pay for the 2123 bushings knowing the mounting success rate might be 2 out of 3-4. That's still cheaper than whole new dog-bones. If the nylon spacers are required to keep it centered then once those are fabbed the first time they should be easily reusable with each bushing renewal.

I have yet to complete the conversion to the 2123 bushing but should this weekend. I bought 4. The engine is in. My current dog-bone is a 2x4 in compression pressed to the engine cover prop rod bracket.

 

[Dr.Jeff]

If the nylon spacers are required to keep it centered then once those are fabbed the first time they should be easily reusable with each bushing renewal.

Nylon spacers are actually very easy. They are available in a large variety of sizes at hardware stores and are very inexpensive. Just get a couple that are the right size (or very close to it). The ones I showed in a prior photo were just some that I already had on hand left over from a prior project. That's why they are too big of a OD for this use, but I wanted to see how they could be used if needed. And it seems they are needed as I suspected. Those came from a local ACE Hardware, but more appropriate sizes are also available in various ID's, OD's and widths. Basically they only need to fill the gap between the rubber (which is narrower than the stock ones) and the body mounting brackets. That will prevent the rubber from creeping off center on the inner metal sleeve.

As a side note, the old stock dog-bone's rubber inserts (that were replaced with these 2123 items) were also distorted off to one side. The rubber on one end of the bone was 'stretched' over to the right and on the other end it was pushed to the left. So there is some sort of ill alignment between the engine and the chassis, at least as far as this strut's location is concerned. As I mentioned earlier, I'm not sure if that is due to the engine/trans weight being off balance relative to this mount, the other mounts being worn, or just a bad design of the unit...likely all three. So it really isn't much of a surprise that the replacement inserts are being pushed over. I suspect the same would happen to any replacement strut used in this application.

Regarding finding a torque strut from another vehicle to use. Keep in mind the inner diameters of the center metal sleeves (where the mounting bolts pass through), and the width of those sleeves also needs to match up to the Fiat design in addition to the length and overall configuration. It will be great if something like that could be found however.

 

[AKimball92]

I believe the 90 degree offset would make for a better mount design. That sort of change would be down to the individual owners should they want to correct the bushings sliding to one side. There are always projects at hand to improve our vehicles.