Rear Seal

["Larry & Sandi Miller" <millerls@ado13.com>]

The following comments are based on the installation on a 948. The seal
worked perfectly but had to be removed when I installed the 5-Speed.

The rear main oil seal I used is the one sold by Mini Mania and requires
some machining.

It comes with a new crankcase rear cover, this is the half moon shaped piece
that completes the circle around the crank with the rear main cap on the
bottom and along with the rear main cap acts as the oil seal.

The new piece is bolted to the block in place of the old and the upper half
of the seal carrier mounts to it.  The lower half of the seal carrier bolts
to the upper half.

According to instructions the new crankcase rear cover and the rear of the
main bearing cap should protrude from the block exactly the same amount (10
to 11 mm). When the engine was produced, the rear main cap was  cast and
then machined in place to fit perfectly(for a while).  The rear end of the
cap however was not machined and was left as cast. The lower half of the
seal carrier needs to fit flush against the rear main cap and unless it
extends exactly 11 mm  (the thickness of the new crankcase rear cover) the
seal between the carrier and the rear main cap will not hold, hence the
machining.

After looking at this thing and talking to a machinist, we decided the best
way to get this to work was to bolt the rear main cap and the new crankcase
rear cover to the block and mill them at the same time to insure that they
are flush with each other.

Out of the box, and assembled on the engine one side of the cover was higher
and one side of the cap was higher.

Larry Miller