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Fabricated Torque Strut for the 2000+ Northstar

33K views 51 replies 16 participants last post by  vincentm 
#1 ·
I made an attempt at fabricating one today. I used a 13" long piece of 3/4" thin walled conduit. Flatten 4" and bend a 90 at the end. Drill through the strut and the radiator brace (be careful of the radiator hose on the other side). I think I used a 3/8" drill and a 3/8" round headed, square shanked carriage bolt. The round head will prevent any abrasion of the radiator hose should they come in contact as they are pretty close (better safe than sorry). On the other end, drill through the engine lift bracket and the strut at the same time. Insert a screw or bolt and nut it from beneath.

Picture four shows an existing threaded bolt hole in the head that I am going to try to fabricate another one for on the passenger side tomorrow.

2000+ Seville application is slightly different and are the first 2 pics on the top row (drivers side and passengers side respectively). Last one and second row are for the 2000+ Deville application.
 

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#3 ·
Re: 2000+ Torque Strut

PART 2
Here is the right side strut and the finished product all back together. With both in place there is MUCH less engine movement. It is not rock solid and the crossbrace still flexes a bit even though the right strut is nearer the end of the crossbrace and has more support, but it IS a BIG improvement and flex is minimal.

Same dimensions on the strut as above. I used a 2" long 1" diameter steel rod as a stand off. Drilled through with a 25/64th drill bit. Did this on a lathe. Then used a 3/4" end mill to mill a U in the end of the strut. I then placed the U'd end of the strut on the stand off and beat on it to open up the two fingers of the U (do this before you flatten and bend it). Then I brazed the strut to the standoff (you could weld if you wish). A trip to the hardware store provided the 3" long smooth shanked M10x1.5 bolt (the smooth shank is a perfect slip fit to the 25/64th hole with no play). What is not shown in the picture is the missing radiator support brace. You will find when it is installed under the torque strut that the bolt head is under the flattened end of the torque strut and you will need to cut a notch in the flattened end of the strut. You will also need to cut two reliefs in the black plastic radiator cover to compensate for the struts.
 

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#4 ·
Re: 2000+ Torque Strut

Ranger that looks pretty good- the original driver's side torque strut was mounted to the bracket where the fuel rail is fastened on, just like where you fastened it in the photo. The passenger side was bolted across the face of the head with three bolts. There won't be any problem with too much stress on the head, don't worry about that.

Perfect, Ranger. Head bolt problem solved, now the motor mount problem is almost solved, we're going great!

AJ's mount might still do the job- I'd like to hear more about his mounts. But the torque strut idea is the answer.

I'm scrapping a 2001 Deville (bronze/black interior)- unfortunately I need the engine from that car before I can use it as a mock-up, so I'll either need to re-install a junk engine or talk to a future customer about doing some testing on the Deville body.
 
#5 ·
Re: 2000+ Torque Strut

I agree Jake. I think the struts are far more important than the mounts. Good to hear you say there should not be a problem with excessive force on the head. I appreciate the feedback. It still rears back, but not near as much. Over all I am happy that I have minimized the movement and have probably lengthened the motor mount life. Maybe even prevented the need for replacement. I think I recall someone mentioning that the movement causes A/C line flexing and eventual failure at the manifold, so maybe I have I have fended off two potential problems. I probably should paint them someday so they look better, but right now it is function before beauty.
 
#6 ·
Re: 2000+ Torque Strut

The only thing I would be concerned about is the constant flexing on the radiator crossbrace. If it's only a little bit, it will handle it. But too much and the radiator might move back and forth. If it does that I'd be a little worried about the end tanks cracking and hoses chaffing. I don't think it would be an issue but it wouldn't hurt to monitor this for a bit.
 
#8 ·
Re: 2000+ Torque Strut

Ranger and I have been bantering back and forth over this engine torque control thing. Some time ago I postulated that a cable snubber from the cradle to the top of the front motor mount bracket would accomplish torque control, similar to using chain with a tad of slack to snub the twist of a longitudinal engine. (Think: older Camaros and Chevelle-type platforms.)

There's a company named Norseman that makes a whole line of self-installed cable terminals, primarily designed for sailboat mast rigging, which requires some incredible load control. With a bit of trial and error and some 3/16" or 5/32" s/s 7x19 wire rope (aircraft cable) and a couple of proper end fittings you could make a snubber with 1/2" of slack, enough to allow everyday engine vibration control, but when you stuck your foot in it the snubber tightens and anchors the engine. Who gives a hoot about a tad of transmitted vibration on a WOT ?

Someone else in here used a couple of turns of wire rope, around the mount bracket and cradle, to accomplish essentially the same thing. Cheap galvanized wire rope from the hardware store and a couple of bulldog clips and you're good to go.
 
#11 ·
Re: 2000+ Torque Strut

Ranger and I have been bantering back and forth over this engine torque control thing. Some time ago I postulated that a cable snubber from the cradle to the top of the front motor mount bracket would accomplish torque control, similar to using chain with a tad of slack to snub the twist of a longitudinal engine. (Think: older Camaros and Chevelle-type platforms.)

There's a company named Norseman that makes a whole line of self-installed cable terminals, primarily designed for sailboat mast rigging, which requires some incredible load control. With a bit of trial and error and some 3/16" or 5/32" s/s 7x19 wire rope (aircraft cable) and a couple of proper end fittings you could make a snubber with 1/2" of slack, enough to allow everyday engine vibration control, but when you stuck your foot in it the snubber tightens and anchors the engine. Who gives a hoot about a tad of transmitted vibration on a WOT ?

Someone else in here used a couple of turns of wire rope, around the mount bracket and cradle, to accomplish essentially the same thing. Cheap galvanized wire rope from the hardware store and a couple of bulldog clips and you're good to go.
This makes sense but would it save wear and tear on the mount? Is it compression or expansion that causes the mount to give?
 
#10 ·
Re: 2000+ Torque Strut

Well, I tried to measure the movement (flex) of the crossbrace, but it was to little to be able to measure standing in front of the car with a jittery wife behind the wheel trying to do the brake torque. :rolleyes: Anyway, I'd say it flexes 1/8", maybe 1/4".
 
#12 ·
Re: 2000+ Torque Strut

The mount, for all practical purposes, just sits there under normal driving conditions. Under passing power demands or WOT the mount stretches (lengthens) so a snubber restricts breaking the rubber band. Who gives a hoot about a little vibration less than 1% of operating time ???
 
#15 ·
Ranger, from what I remember the last time I did this, the brake lines are run parallel to the engine cradle and are secured to the cradle with one or maybe multiple plastic clips. However, there is a gap, perhaps a quarter of an inch, between the cradle itself and the brake lines (such gap being created by the plastic spacers/fasteners). What if you wrap the cable around the cradle behind the brake lines instead of over them? In other words, thread the cable through the space between the brake lines and the cradle itself.

One user suggested wrapping the cable around the motor mount bracket. This is what the first diagram depicts. Another possibility, which seems like it may be a better way to really make sure that the mount doesn't become overloaded, is to wrap a cable around the engine cradle, and then secure the free end of the cable to one of the bolts that secures the motor mount bracket to the cylinder head -- thus creating a direct tether between the engine, and the subframe.

I forget who came up with this idea, but a user suggested using tailgate cable (which has eyelets on both ends) to accompish this. I think that you can thread the cable around the subframe (behind the brake lines), then run the loose end of the cable through an eyelet, to create a lasso almost, around the cradle. Then you take the free end and attach it through one of the bolts that secures the motor mount bracket to the cylinder head. This type of "tether" will almost certainly prevent the motor from kicking back too much. That way, when driving normally and idling there isn't any NVH (thanks to the hydraulic motor mount) but upon aggressive acceleration, that tether stops the engine from kicking back, saving the mount from stress.

Click the thumbnails to enlarge:



 
#16 ·
Well I've busted 2 motor mounts so far with my 94 eldo, much less of a problem than the 2000+ type of motor mount. However, what I'm planning on doing when I replace it again is to put a couple of large hose clamps around the new one (Easier to do with the older style because of it having 4 studs rather than 2).
 
#18 ·
Like anything, someone has to try that idea to see how it works. The hose clamp idea is only feasible for the pre-2000 models, which have a square-shaped front mount. The 2000+'s circular mount with very little flat surface area to attach a clamp would just cause any type of clamp to slip off.

The thing is, I think that a hose clamp (with pretty sharp metal edges to it) might backfire on you and actually cut into the rubber, causing the mount to break quicker.
 
#24 ·
Krashed, Hie thee on down to your local sailboat rigging shop, take a look at some of the s/s wire rope work, and tell me that it's anything but efficient and good-looking (plus being hellishly strong).

Wire rope (aircraft control cable) and chain have been used for just what this thread is all about since before I was born.
 
#27 ·
I'm still a little new to N* game so I'm a little confused on this engine mount deal.

So are 2006+ like mine:



Problem free? I only see that one on the left.

However on 2000-2005 Devilles I don't see any upper mounts.

My Eldorado has these:



Both of the arm's bushings are shot. And I'm quite sure they need to be replaced.
 
#30 ·
GM first quit using the dogbones on the 5th Generation 1998 Seville. I'm sure this was to save costs over the previous generation. Then the Deville followed suit in 2000 when it switched over to the Seville's G-body based K platform and it stayed like that until 2006 when GM switched over to the DTS name and went back to the old dogbones. The Eldorado always had dogbones, even after the 2000 revision that went to COP ignition. I wonder though did any G-bodies use dogbones? The G-body platform included the Aurora, and was the basis for the '98+ Seville and '00-'05 Deville though both of those use the designation K-body.

It also makes me wonder if the elimination of dogbones led to quite a few of the suspension problems these cars suffered from. I'm sure it didn't help, but then again I don't think it caused it because a few of the '06+ DTS's i've driven still shake.
 
#32 ·
It was all done on the fly. The pipe was 3/4" conduit that I had lying around. Both sides are 13". It fits almost perfectly into the lift bracket on the drivers sdie. Drill completely through. Drill size is irrelevant. Just drop a long screw through and put a nut on the bottom. Now you can mark the conduit for where it need to be bent (12"). Take it off and put it in a vice and flatten 4". Then bend a 1" tab at a 90 degree angle. Now you'll have to drill through the front support. Be careful as the radiator hose in on the inside. I realized that the hose would be rubbing on the bolt head and I did not like that so I use a round headed carriage bolt with a square shank. As the nut drew it in the shank turned the round hole square and locked the bolt from turning. I think I might have bent the dip stick tube over a 1/4" or so.

Passengers side was similar except that I had to make that standoff spacer out of a 1" dia. steel bar stock. I measured the length I needed (2"). Then went to the hardware store and bought the correct size and length metric bolt I needed (I think it was 10 X 1.5). The bolt needs to be about 3" long. I measured the bolt diameter and drilled through the spacer with as close a drill size as possible (25/64") to elevate any play. Then I used a 3/4" end mill to mill a U in the end of the conduit. You could do that with a saw and file or a Dremel. It wasn't a real good fit so I beat the conduit into submission as it straddled the spacer. Then simply brazed (or weld) it on as the picture shows. There is a bit of a problem with the other end in that it interferes with the radiator hold down bracket. Since it does not show, I simply removed the bracket, drilled through, cut a slit in the bracket lip and flattened the lip on the radiator hold down bracket so it will fit over the top of the torque strut and remounted the bracket over the flattened conduit. It sits a little uneven, but it's functionality has not been compromised and is under the cover anyway. You will have to cut, mill or file a clearance notch in the flattened pipe to reinstall the radiator bracket mounting bolt. All in all it is pretty straight forward. Just measure cut and bend. The hardest part is making the spacer, but you could probably us a piece of black pipe or such and cut to length. A little Yankee ingenuity always helps. If you do not have any welding capability, you'll need to find a friend or a shop. Can't imagine a shop would charge much if anything at all. Hope that gives you some incite. Let me know if you have anymore questions.
 
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