: Motor mount advice

03-26-10, 10:13 AM
I believe I have a broken front center motor mount. There is a slight clunk when hitting the accelerator from a coast, and now that I think of it, the shift from 1 to 2 during WOT was a little rough.

Is it best to just have to dealership supply the part, or should I buy elsewhere and supply them with it? Jake, do you still have those mounts??

Also, how long should I drive with a bad mount? Other than being annoying, is it going to hurt anything if I drive like grandma until I have it fixed?


03-26-10, 03:38 PM
If you drive it easy you can get away with it for a while, but be advised that even under light acceleration the motor is torquing and that flexes the coolant, P/S and A/C lines.

03-26-10, 04:22 PM
After having my father observe the engine while I put the car in D, applied the brake, and revved it to 1500 RPM, the motor mount does not appear to be broken.

MiL32T0N3 iNDU2TRi32
03-27-10, 02:56 PM
I would grab a flashlight, crawl under the car and inspect all 3 mounts, you have one up front and center, one at the rear of the motor on the passenger side, and one directly in the center of the driver side wheel well. When I did my HG job I felt like I wouldn't have to replace my motor mounts and after doing my initial inspection before pulling the motor I realized that 2/3 where very worn even though I did not see/feel any symptoms...

04-01-10, 08:03 PM
Would there be any way to beef up the dogbones, or better yet add my own version? I have a 97 Deville Concours with the 2 dogbones that connect to the upper radiator support bar. The engine will jump back about 1-2 inches when accelerating.

I did examin the motor mounts when I had the engine out.....They didn't appear to be broken.

I noticed that some members have made custom mounts that are used on the 2000 and up northstars.

Would it be safe to do the same for my northstar.....I was going to custom make some new dogbones that would help limit the rollback on the engine.

Will I damage the head on the engine If there is two much rollback on my shorter dogbones? On the other posts it seems to be alright.......and also, that upper radiator support bar is really strong. That was my lifting point when dropping the cradle....It didn't seem to flex to much.......

I want to be able to pass someone at WOT and not feel the engine rollback and the awful vibrations that come with it.........any help or suggestions would be appreciated......Thanks Ryan

04-01-10, 09:04 PM
I am surprised you are getting that much movement with the factory dog bones. I assume you are talking about my fabricated torque struts for the 2000+ engines. You could do that, but since you already have the mounting points, if you wanted to stiffen it up even more (like mine), I would pop out the rubber bushings in the dog bones and machine a steel or aluminum press fit bushing. That would pretty much lock that puppy in place (like mine). The only flex you have is in the rubber bushing.

04-01-10, 09:13 PM
Hey Ranger, so you don't think I would jeopardize the head? I worked so hard on this engine and the last thing I want is a head pulling off at hard accelerations........If not I'll give it a try...Thanks Ryan

04-01-10, 09:32 PM
I don't think so. If you look at the pics I posted in that thread you'll see that my right torque strut is bolted to the head. The left is bolted to a bracket on the crossover manifold. No problems so far. I think the factory dog bones are mounted to the heads if I am not mistaken. Haven't seen one in some time so I'm not sure, but Jake makes mention of that in the thread.