The slots are there to allow the studs to pass through them when the engine
is lowered into position because of the angle of the mount faces and studs
(in fact you may have to insert one side and position it at the top of its
slot before you can get the other stud in, then centralise them), as well as
to cater for any *horizontal* alignment tolerances. Any vertical
differences from car to car are a factor of the the horizontal diatances and
the compressability of the mounts - it is not possible to adjust the height
of the engine in the chassis using these slots - unless one uses additional
spacers, of course. Interestingly, although the V8 uses the same mounts and
has shims the shims aren't shown in the manual. However the mounts should
be installed so that the stud that goes through the chassis bracket must be
in the *lower* of the two possible positions, and since the shim has its
hole offset it would make sense if this were to be in the lower position too
so it fully covers the mount - this is how I fit my V8 shims and how Moss
shows it.
PaulH.
----- Original Message -----
From: Bud Krueger <bkrueger@ici.net>
To: MG List <mgs@autox.team.net>
Sent: Wednesday, December 27, 2000 3:37 PM
Subject: Engine Mount Shim Orientation, 77B
> Hi folks,
>
> Just ran into a puzzler while installing new motor mounts into my 77B.
There is
> a vertically oriented slot cut into the the motor mount piece that is
welded to
> the frame. A rectangular piece of steel (I'll call it a shim) with a bolt
hole
> offset from the center in one dimension, goes under this slot, between the
mount
> and the lock washer. I'll refer to the distance from the bolt hole to the
edge
> of the shim as the short/long dimension. This shim is shown on page 64 of
Moss'
> MGB-14 catalog, just to the right of Item #91, Engine Mount. The puzzle
is
> "which way does it go?"
>
> When I removed my motor mounts, both sides had this shim oriented so
that
> there was maximum coverage of the slot, i.e., the short dimension was
down. In
> this orientation, the upper edge of the shim is against the upper inside
edge of
> the mount and the bolt hole is just into the slot. My engineering sense
tells
> me that the slot is probably there to allow vertical adjustment of the
engine.
> Otherwise, why have the slot, why not just drill a hole in the mount? If
the
> shim is oriented so that the short dimension is toward the top, the mount
can be
> positioned vertically and the shim still acts as a stiffener. Anybody
have an
> answer to this one? TIA.
>
> --
> Bud Krueger
> http://home.ici.net/~bkrueger/
> 52TD
> 77MGB
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