Hi Guys,
Need a bit of advice....

I have just bought a used 300Tdi engine out of a Disco with a 200Tdi Defender Flywheel housing attached (This is to mate an R380 via an Ashcroft Stumpy Bell-housing).

The flywheel had to come off to skim/face it ready for the new clutch and I thought whilst it was off I would (if needed) replace the rear oil seal.

Further, before I can attach the Stumpy I need to tap 4 x M8 holes at the bottom of the flywheel housing to become M10 studs - this would be much easier with the flywheel housing itself on the bench.

The first picture shows whats installed at the moment, the second is a new and what I believe to be, an Original Equipment seal.

Picture 1:

Current 200Tdi Rear Crank Oil Seal by Jon_Kelly, on Flickr

Picture 2:

ERR2532 - 200Tdi Rear Crank Oil Seal (OEM) by Jon_Kelly, on Flickr


Question:
As the current seal is not leaking would you leave it as is and tap the M10's in situ? In doing this I am concerned about 2 things:
1) that the current seal is on the visible side at least, made of Aluminium whereas the OE seal I have is rubber and much more like every other Land Rover seal Ive replaced in the past.
2) That I won't get the threads started straight as nothing will be square.

Tapping the M10 studs to accommodate the Stumpy bell-housing would be much easier with the flywheel housing itself on the bench as it will be easier to make sure everything is square and straight, but will obviously mean replacing the oil seal.


Thoughts and advice please...

Thanks
Jon