Testing Original Custom's Upgraded Speedo Drive Seals, Initial impressions and installation. Options

[Sleepin]

My wife's '73 was leaking a huge amount of oil out of the speedo drive. I contacted McMark to try out his newly designed speedo drive.

As you can see, this drive was leaking quite a bit. Just sitting in the garage it would drain out a major spot just in a couple days.
(IMG:http://www.914world.com/bbs2/uploads_offsite/i171.photobucket.com-179-1269017475.1.jpg)

Here is my core sitting next to the new unit. Notice the extra O-ring:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i171.photobucket.com-179-1269017476.2.jpg)

The swap was straight forward. The only difference I noticed from a regular speedo drive was a little persuasion required to very lightly tap the drive into position. I just used a small rubber mallet to accomplish this. I am confident that I did not pinch the O-rings, and it felt like a good solid seal. Once in place without the set screw in, I could not wiggle or move the drive from side to side at all.

A quick fill of the trans:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i171.photobucket.com-179-1269017477.3.jpg)

A quick wipedown to get rid of any oil:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i171.photobucket.com-179-1269017477.4.jpg)

Also put a strip of cardboard underneath the trans...I want to make sure this isn't going to leak.
(IMG:http://www.914world.com/bbs2/uploads_offsite/i171.photobucket.com-179-1269017478.5.jpg)

I will snap another picture underneath in a couple days. I highly doubt that this will leak at all! Such a good idea IMO...I wonder why no one thought of this before!

[1968Cayman]

The problem with the 914 speedo drive is that they used aluminum in a magnesium case. Different expansion rates means leaks. On the 911, Porsche used a brass speedo drive. Same expansion rate as magnesium. Change the drive for the brass one, and it doesn't leak.

But those suckers are hard to find. This should be a good alternative solution.

Sorry to jack the thread, but do you know if a drive from a 911 Sporto would work in a 901?