IIRC, the Volvo Diesels of the early 80s were a 5 and/or 6 cyl. version of the oil burning 4 banger in Rabbit/Golf diesels.
These Volvo diesels had a bad problem of lubrication starvation in one cylinder.
Is it possible to tap and plumb an auxilliary oil line into the head to eliminate this problem?
VW used the 4 cylinder version, Audi used the 5 cylinder version, and Volvo and the German army used the six cylinder version.
Yup, we shared an engine with the guys that are 0-2 in the world war category. 
While that engine had many issues, oil starvation is not one I have ever heard of.
Oil leaks? Yes, very messy engine. Broken belts? Yup. customers would not change the belt, and it would break destroying the valves and breaking the camshaft into several pieces. Smoke? Yup, that too until we finally learned to fix/prevent that.
Oil starvation? Never heard of it.
A thread on another board with oil starvation highlighted:
http://64.233.169.104/search?q=cache:Nr9BGQRAhgsJ:www.thedieselstop.com/forums/f33/friend-bought-1983-volvo-diesel-car-109348/+volvo+diesel+vw+oil+starvation&hl=en&ct=clnk&cd=5&gl=us
Apparently, the advice is to use Mobil 1 synthetic to avoid problems.
From the very last post in that thread
"The oil system problem he says is a rumor. Good luck!
my comment exactly. I have worked on, and taught other technicians to work on these engines since they were brand new and under warranty. I have never seen or heard of an oil starvation problem on any one of them.
I don’t know what else to tell you, except I doubt you will find anybody that knows more about that engine than I do.