Rek
Well-Known Member
I have performed some research, if you can call looking at the individual mounts whilst revving the engine research.
The left side mount seems to take little load. The right side mount squashes when the engine is revved and the engine twists clockwise on the axis of the right mount very slightly. The rubber softens when the car warms up, as its just below the exhaust, exacerbating the squashing/twisting and making the engine movement more pronounced. I have found that the problem I have is more pronounced with a warm car and is only really relevant in first gear when pulling away. This is when the torque through the mounts is probably at its highest.
There is a lot of rubber in the mount which means more compression is possible.
So, the solution might be to investigate E34 mounts. The original mounts were for a car with 170 bhp. Putting 256 bhp 0r even 211 bhp for a 535i through the car might well test the original mounts.
Another solution might be to beef up the mount on the right by using a stiffer aftermarket part. I feel I can leave the left hand side as is unless the dimensions are different. I just need to get the dimensions of the E34 part now to check its the same, or a feasible engine height.
I know it might sound stupid, but a heatshield preventing a build up might be feasible, if a little of an overkill.
I cannot be the only one with this problem, so I will post the results.
As always, everyone is so helpful.
Don - the centrebearing is Febi. Once in the air I will investigate but it has less than 2,000 miles on it.
Stevehose - thanks for the advice. My driveshaft was flush with the output shaft face, such that I don't think the tightening of the bolts would have produced an imbalance. Also, once going, the draintrain seems fine, or at least fine enough to leave tuning it further for another day.
The left side mount seems to take little load. The right side mount squashes when the engine is revved and the engine twists clockwise on the axis of the right mount very slightly. The rubber softens when the car warms up, as its just below the exhaust, exacerbating the squashing/twisting and making the engine movement more pronounced. I have found that the problem I have is more pronounced with a warm car and is only really relevant in first gear when pulling away. This is when the torque through the mounts is probably at its highest.
There is a lot of rubber in the mount which means more compression is possible.
So, the solution might be to investigate E34 mounts. The original mounts were for a car with 170 bhp. Putting 256 bhp 0r even 211 bhp for a 535i through the car might well test the original mounts.
Another solution might be to beef up the mount on the right by using a stiffer aftermarket part. I feel I can leave the left hand side as is unless the dimensions are different. I just need to get the dimensions of the E34 part now to check its the same, or a feasible engine height.
I know it might sound stupid, but a heatshield preventing a build up might be feasible, if a little of an overkill.
I cannot be the only one with this problem, so I will post the results.
As always, everyone is so helpful.
Don - the centrebearing is Febi. Once in the air I will investigate but it has less than 2,000 miles on it.
Stevehose - thanks for the advice. My driveshaft was flush with the output shaft face, such that I don't think the tightening of the bolts would have produced an imbalance. Also, once going, the draintrain seems fine, or at least fine enough to leave tuning it further for another day.
