Check the compression.  You probably have a lot of blowby which was
exacerbated by the valve job. The DOHC engine is known for premature
self-destruction of the ring seal but I don't know if the SOHC has
similar issues or not.

One of the tests for a burned or leaking exhaust valve is to put rag
over the tailpipe and look/feel for a pressure/suction sequence. The
suction will indicate a exhaust valve leaking and allowing flow up
through the exhaust system on the intake stroke of the affected
cylinder.

In article
<1147780577.865874.20520@i40g2000cwc.googlegroups.com>,

Your head bolt torque specs are wrong, should have been
[step 1] 22 ft.lbs, [step 2] 33 ft.lbs (two passes) and an
additional 90 degrees.

Torque to yield bolts, which means you shouldn't re-use them.

That really doesn't sound right to me...  might want to recheck those
torque specs.  I've never heard of a spec that called for a torque and
then backing off and retorquing to a lower spec.  I would expect that
these would be TTY bolts like many smaller modern engines meaning that
you would torque to a certain torque value (in one or more steps) and
then add a final tightening in degrees.  If the torque spec is *only* a
torque value you are probably OK reusing head bolts but if they are TTY
(i.e. the final tightening step is expressed in degrees) they should
have been replaced.

not in my experience.  You should get pulses, but I wouldn't think
you'd see any reversion at the tailpipe unless you've got some
seriously radical cam timing.

Here's something to think about though... one time I was helping my
friend resurrect a "barn car" '56 Golden Hawk.  We fixed the brakes and
dumped ATF down the plug holes, got the engine to spin over (it was
lightly seized) then changed the oil, spun it up until oil pressure
came up, changed the points and condenser, and went for a drive.  Car
actually ran pretty well, and my friend was driving when he decided to
get on it a little going up a long hill.  Next thing you know there was
this HUGE cloud of light grey smoke following us... fearing the worst,
he drove slowly back to the garage for a post mortem.  Only unusual
thing that we found was evidence of a mouse nest in the driver's side
tailpipe.  After driving the car another hundred miles or so, the smoke
stopped.

As best we can figure, what happened was little critters built nests
inside the exhaust system of the car, blocking the driver's side of the
exhaust downstream of the mufflers, which were glasspacks.  All the ATF
that we'd poured down the cylinders ended up going out the exhaust as
you'd expect; but the ATF that blew out the pass. side exited before
the engine got really hot.  When he stuck his boot in it, he blew out
the mouse nest and all that ATF that was soaked into the 'glass in the
driver's side muffler suddenly ignited, causing the huge cloud o' doom.
At least that's the best explanation I can come up with, since the car
didn't seem to lose fluids in any alarming quantity, didn't overheat,
miss, etc.

Any chance something like this happened to your car?

As a final note, I have seen a few smoking Saturns, but they all seemed
to be burning oil.  Any chance what looks white in your rear view
mirror is really a light blue?

nate