Keep driving my 79 300d with oil leaking?

[mrbisset]

I have been working on my 300d for the few months I've owned it and got it running ok. i drive it to work everyday as long as its not too cold and it doesn't start, but its leaking oil pretty bad and burning it too. Thanks to help from this forum, I got the car started after a few years of it not driving, ran diesel purge in it, replaced the battery, and adjusted the valves. The starter is intermittent and it doesn't engage about 75% of the time. I like driving it, but have been thinking about how long can I keep it going...I have done a compression test on the front 2 cylinders and they are around 210 psi...pretty low. I couldn't get to the rear glow plugs easily so didn't test them yet. But when I loosen the oil filler cap while idling, it wants to blow off! a sign of blown rings? the other problem is that I am leaking oil down the passenger side of the engine pretty good...its covered in oil and I am adding about 1 quart/100 miles. i checked the valve cover gasket i replacedand it looks ok, no signs of leaks...it has to be coming out somewhere else. I do all the work I can on it myself, but being my first Benz, i don't know where to start troubleshooting oil leaks and am thinking of have someone else look at it.