I just read through this thing last night and I think I skipped over it the first time for some reason but there's a lot of stuff in there that makes sense, and a couple things I'm still trying to wrap my head around. I can see the gummed up ring causing the oil burn with the throttle plate closed and excess pressure and such, but the only reason I see this going away is because the cat warmed up enough to hide this problem. The idea of sufficient expansion in a short period of time seems like a bit of a stretch for me but I do intend to run through the different scenarios people have commented on to get a concrete idea of the scenario that causes the cold start smoke.
There is a very simple test to see if the oil is coming from your valve seals or your rings,...
Run your car hot for a good run then shut it off and let it sit all night.
In the morning, pull your plugs and look down each cylinder and check for oil on top of your pistons.
If they are wet with oil,.. your valve seals are leaking.
If they are dry, put your plugs back in, start your car and run it
for about 20 seconds and shut it off.
Pull the plugs again and check for oil again.
If the pistons are wet with oil, then your oil rings on your pistons are seized.
Keep in mind, there is really only three places the oil can be coming from,... Valve Seals, Oil Rings, or Head Gasket.
If the head gasket was leaking, it would most likely leak into the coolant or onto the ground as well.
If the valve seals are leaking, there would most likely be oil on the pistons in the morning and burn oil all time.
If the rings are seized THEN you get the specific huge cloud of smoke for about a minute, IF you believe the Croatian mechanic who figured out the issue.
For those who are having a hard time wrapping your head around the oil rings doing everything so fast,... I'm thinking of it like this,...
The oil ring on a piston had very little mass and would need a lot less time to heat up and expand. The oil that would cling to the cylinder walls (after not being scrapped away) would be very hot from being in with the combustion and then deliver that heat to the oil rings in short order.
Either way,... It doesn't matter,.. I simply believe the dude from Croatia,... nothing is 100% definitive but his observation and explanation is pushin over 90% for me,...
Keep in mind, anyone burning oil may very well have BOTH valve seals and rings being a problem.
I still have to put up my pictures and even though it's still smoking, the amount of smoke has decreased and my pinging is gone. So the head didn't resolve my problem but it did make a difference in the running condition of my car.
I'm guessing that your brand new cylinder head and all the components down stream will be fouled up in very short order,... then your pinging will come back,...
I think you should do the early morning spark plug test then expect to do your rings,...
P.S. I don't burn a drop of oil and DO believe it is maintenance related,... I change my oil every 3000 miles and put 1/3 of a can of seafoam in with the NEW oil and leave it in there.
My used oil looks almost as clean as my new oil going in,... the sludge and varnish has been removed and is constantly being cleaned.
ANY oil over time picks up dirt, varnish and acids from combustion which is stored in suspension and circulates through the engine.
Perhaps synthetic oil itself can last for 7,500 miles but it's carrying 2 1/2 times the dissolved plaque just waiting to coagulate and plug the tiny little heart arteries of our FS engine.
My car is on blood thinners (seafoam) She's healthy and happy and I'm not worried about burnin the oil,...