: Question: Is it possible to drill and tap a hole for the torque strut on a 96 north*?

08-26-10, 02:23 PM
I'm looking at trying to install a 1996 northstar in my 99 STS. Is it possible to drill and tap the extra holes required for the torque strut on the passenger side wheel well? I'm talking about the changes made in 1998. I'm thinking its not possible but has anyone had any experience with this?


08-26-10, 09:11 PM
I don't want to do anything that will compromise the integrity of the engine. If its safe to do though I would like to find a way to use the engine.

08-27-10, 07:45 PM
My next idea. To see if its possible to make a 96 engine into a 98 type with the extra holes for the torque strut on the front of the engine by swapping the lower ends. I have an extra lower end from an engine that seized up (my original engine) and am thinking that it may work without having to tap anything. This would allow me to mount the 96 into my 99 sts without tapping anything. I won't have to disconnect anything (except maybe the main bolts). Only draw back: I have to reseal the lower girdle. That plus take the heads to a reputable machine shop in Lafayette plus Jakes studs. I should have the equivalent of my original engine. On my way home now so I should be able to analyse my original engine when I get there.

08-28-10, 10:01 AM
I think the timing chain cover is different. And I don't believe there's any material to drill and tap behind the cover on the pre 98 blocks. I have a 96 block in my 99 Seville. what i actually did was I grinded some material away on the aluminum bracket where it touches the cover I removed enough to bolt the bracket to the block with out it touching the cover I know its sound s shade tree but I was in a bind and needed my car.Also the hole you are refering to is for the front (left?) engine mount not the torque strut.

08-28-10, 06:35 PM
Correct. Right next to timing cover. I've been studying the designs. I'm wondering if I can use the lower engine girdle that has my hole already there? How are these blocks cast? In seperate pieces or as a unit then split?

08-29-10, 11:34 AM
The block/cylinder liner unit is one piece, the lower block half/main bearing cap/ stud girdle is another, and the oil pan is a third - all 3 bolt together to form a very rigid assembly. The machining to accomplish this must be quite something to watch.

If you're trying to restrict or damp engine twist due to torque at high throttle openings, you want the damper/strut/dogbone as far away from the center of (torque) effort as possible, hence the dogbones out on the heads on earlier models: it's a LOT easier to restrict motion when the damper is way out in radius from the center of effort. You can mess with 1/2" to 3/4" up around the heads, but you're fooling with only 1/8" to 1/4" of motion down low.

08-29-10, 01:57 PM

08-29-10, 07:19 PM
Actually I'm talking about the extra motor mount that bolts to the engine next to the timing cover. Introduced in 1998 with the redesign of the seville line. I've been looking at both engines and am pretty sure it's possible to convert a 96-97 engine into a 98 -99 engine by swapping heads and the girdle. That way I don't have to mess with crank and rods/pistons.

Update on existing engine: developed a knock so I believe one of rods is comin loose

Update on

08-29-10, 10:09 PM
You must be talking about something I am not aware of. The only "Torque Strut" I am aware of is what we usually call the "Dog Bone". That is what my home made ones replaced.

08-29-10, 11:26 PM
Huh...be careful what you wish for! I have them on my '97 and they seem to only last about 2 years. Not sure if is the way I drive or the rubber bushing is just cooked by the engine heat (as is always cracking on the engine side). Probably the failure is a combination of the two but is still frustrating every 2 years $50 on dog bones. By the way, has anybody tried to press the bushing in/out on these things as I saved few of the older dog bones with one good bushing? The other thing is that every time I buy new ones I spend some time to buff the aluminum to a nice shine and is just work for nothing as the don’t last.

08-30-10, 12:27 AM
See number 19 on the diagram. That's the mount I'm referring to. I've heard it called several things including a torque strut. 98 northstars were redesigned to accommodate this in the seville. Jake has a post about differences bw model years in this forum. To me when analyzing a 96 and a 99 side by side it looks like I could bolt my 99 girdle on the 96 to accommodate this. I have a 96 I was able to do compression reading on but it seems after doing compression reading it was very uneven. Here's the results:
Cyl 2-4-6-8 was 30-60-80-120
Cyl 1-3-5-7 was 210-210-210-175

Bad block I believe so I'm still searching for a good deal on a block

08-30-10, 12:42 AM
That is an engine mount bracket, a torque strut (or dog bone) looks like this:
This is the driver side (longer one), the right side one looks exactly the same only the arm is less than half the length.

08-30-10, 01:24 AM
Ah. Mine didn't have that. The dog bone that is

08-30-10, 12:02 PM
See number 19 on the diagram. That's the mount I'm referring to.
That is a motor mount "bracket", not a torque strut as shown above.

08-30-10, 09:08 PM
The N* equipped Cadillacs with dog bones are: ‘93-’97 Seville, ‘93-’02 Eldorado, the ‘92-’93 Allante and ‘94-’99 Deville, thus a '99 Seville will not have them.

09-09-10, 10:40 PM
Well my torque struts arrived earlier this week and yet again I could not help myself and shaved all the casting defects and then spend a whole lot more time buffing it. This is the right (long) one, the other one is half way done.


At least this time the rubber bushings look little better quality (denser material).

09-10-10, 09:17 AM
I wonder why they stopped putting these in the 98 and newer model sevilles.

09-10-10, 03:21 PM
I think someone didn't like the look....

09-10-10, 08:38 PM
Why '98+ does not have anymore 4 amp and has only one?
Why '98+ does not have anymore the trunk pull down motor?
Why '98+ does not have anymore real wood, but just imitation?
Why '98+ rear doors go all the way down to the wheel (no more wheel arch lip, no more wheel arch trims, generally has less trims)
Why '98+ has a simpler suspension setup on the rear?
Why '98+ lost the power antenna with whinshield integrated ones?
Why '98+ rims have a small (cheap) center cap?
Is all a matter of keeping the cost down, you add some you have to remove some.

09-10-10, 10:01 PM
I see.

09-12-10, 08:39 PM
Why '98+ does not have anymore 4 amp and has only one?...
Why '98+ does not have anymore real wood, but just imitation?

The DHS and DTS both have real zebrano wood up until 2005, the base Deville has imitation.

Do you think the 4 amps were better than the 1 amp in the trunk? I did really enjoy the sound out of my 98 ETC. The 03 DHS sounds a little more boxy--more mid tones. This may be more natural and realistic, but I really enjoyed the 98. Also the DHS/DTS Bose amp is 275 watts while the 98 ETC had 400 (according to BOSE, bc each speaker had its own 100w amp).

The Seville Bose from 98-04 has 425 watts. They're cube speakers basically, whereas the DHS/DTS has tweeters on the pillars instead of more cube speakers.

These below, came from BOSE when I inquired...




09-13-10, 12:02 AM
I decided to go with another 99 Seville STS engine from a salvage yard. It was involved in a fire but ran before the fire and got a 90 day warranty. I decided not to go with any head gasket repairs at the moment just b/c I don't know this engine yet. Going to wait and see how the engine does before doing any repairs. Whether I do it or take it somewhere to be done remains to be seen. Depends on the time I have available on my hands. I will say all my accessories are now new/rebuilt. New ac compressor/accumulator, rebuilt alternator, rebuilt starter. They should all last a long time so I'm happy to say the only things I should now need are a tranny if it ever goes out and the stud kit for the engine eventually. IDK yet what I'm going to wind up doing with the engine that failed on me after being overhauled with new rings and all. Say a little prayer for me. Hopefully the bottom end and heads are good on this engine.

Oh, and btw. I do enjoy the factory bose sound system in the seville. It has an awesome sound for a factory system. I've never been a fan though of any aftermarket stereos or such.