aligning motor mounts-- do it! (re: crossmember..)

[treed2@u.washington.edu (T. Reed)]

Okay, so I feel like a bit of a bozo after what I discovered today..

For a long time I've been meaning to align my motor mounts, but it's
always been one of those "I'll get around to it" jobs. Even when I had my
engine out to put the 2.0 in, I just bolted the mounts back up where they
used to be based on the bolt marks in the caked on grease. At the time I
just didn't want to deal with realigning the exhaust or shift linkage, I
had too many other little jobs to do just to get the motor done.

So today I decided to give it a shot, just because when I peeked under the
car my rear mount looked ever-so-slightly strained. I loosened the
mounting bolts for the front and rear mounts, shook the engine back and
forth a little, then tightened them down again.

When I went and started the car I couldn't believe it. 80% of my vibration
was GONE. I have a poly front mount and a vw motorsports rear mount, which
I'd been told was a pretty shake-y combination.. so I just assumed that it
would be that way no matter what. I didn't think alignment would make much
of a difference, let alone a noticable one. Was I ever wrong!!

Anyway, this new development has me thinking that the front and rear
mounts were carrying at least some of the engine's weight, when they are
supposed to carry none of it at all (they're only supposed to help
oppose acceleration-induced rotation of the engine). Now I'm wondering if
this didn't contribute significantly to my crossmember cracking.. boy do I
feel stupid!

I've owned this car for too many years and have done too much work on it
to have never noticed and corrected something like that. The motor mounts
have been aligned the same way since I bought the car, I've always just
put them back the way they were since I assumed they were correct. Now I'm
smacking myself on the forehead.

So my advice for -everyone- is to do what I did! Loosen your front and
rear mounts and then tighten them again. It only takes a minute, and it
might not just help vibration, it might help keep your crossmember from
cracking.

-Toby