Good afternoon group,

Have a problem on the Vanagon maybe some of you have experienced.

After driving about 5 miles (8km) the van starts to run rough, smokes
(oil), then belches a huge cloud and smooths out and stops smoking.  It
does this occasionally (like maybe once a month.)  Runs fine the rest of
the time.  Outside temp doesn't seem to make any difference.  Though engine
temp is about the same (does it in the same place w/i 1/4 mi.) Level
ground, speed ~50-55 mph (80 kph.) It will do this in the middle of summer
(90 deg F.) or late fall (35 deg F.) Compression is good (120+) on all
four.  Any ideas?  If it was American Iron, I'd think PCV valve, but a 1.9
wasserboxer has no such device.  It has about 50k since the last overhaul
and about 25k since the last reseal.  No coolant leaks, no oil leaks, runs
strong.

TIA for any and all ideas.

Jim