A trick I've used a time or two on troublesome 2 piece seals is to sand the ends of both seals a bit, lay a thin shim (like .010"?) in the block and the main cap, to shim the seal inward, and use a dab of RTV (or better yet, now there is Right Stuff) on the ends of they seal halves where they meet, along with a little RTV smeared on the OD of the seal. Might sound a little cobbled up, but it cured a seal that still leaked after having been replaced twice.
I've cured a bunch of timing cover lip seal leaks with brakleen and some Right Stuff. Clean the whole area up surgically clean with brakleen, then shoot, or smear the Right Stuff in the gap, (as if you were packing a wheel bearing, no air gaps), finish by making a nice smooth "smile" on the joint between the cover and the pan. It WORKS