Possible to replace valve stem seals without removing head?
 

The thing's been using oil alot lately and doesn't leak to any noteworthy degree. When I re-did the balance shaft housings, it stopped sucking oil into the intake, so I'm thinking the rings are in decent shape (originally thought blowby could have been a major culprit). It compression tested pretty well a few months ago (~150-160) which leads me to believe the only other way it could be burning oil is through the valve stem seals, or is it possible to have worn out just the oil scraper rings and still have decent compression?

Anyway, I want to start with the cheap and easy first. I know I've heard you can pressurise the cyl with air, which holds the valves closed in order to release the spring and get to the seals, but does it work on a 944 motor?

Here's compressing the spring from the top on a 928 head.

http://forums.pelicanparts.com/uploa...1244478999.jpg

yes, it will work on that engine. a 16 valve would be a little more trickier.
first, tap loose the retainer with a hammer just to break it loose. then use the air and that tool above (OR something like it) to get the retainer off. just don't drop the keepers!

The "low tech" way is to take some cotton rope and feed it into the spark plug whole until the combustion is full. This will keep the valve from dropping. It's obviously easier if the piston is at the top of its stroke.

put some rags in the oil return holes so you don't drop anything in there.

Use a compression tester hose, thread the end into the spark plug boar and add an air hose fitting nipple to the other end. Connect to an external air compressor. This will keep the piston susspended in the valve boar. release the spring and retainer. We do it all of the time when replacing them here on any of the 4 or 6 valve engine we service.