I have 1990 honda civic it has good compresson

it is a rubber seal that keeps oil from running past valve and into combustion chamber,requires head removal and disassembly.Usually caused by letting oil get low causing seal to dry up and crack.

Hm. In my experience if you lose oil at the rate of 1 qt. per 800 mi. it's going somewhere. Actually, if you lose 1 qt. per 1000 mi. and change your oil every 3,000 mi. it's under $10 in oil you have to buy to keep it topped off, and some places say that's there's nothing wrong.

But, your case is a little more serious.

I think that it's probably leaking past the rings and/or valves and the catalytic converter is eating up the oil, so you see no blue smoke, like you would in a car that has no converter (I'm assuming you have a catalytic converter on your car as my 1981 Honda had).

After 100,000 mi. little irregularities in the piston cylinders can develop, and seals can gradually degrade. So, this is normal for that kind of mileage, although there are people who get over 400,000 mi. on their cars with just regular maintenance and driving highway mi.

You might want to try one of those slower burn oils designed for cars with 75,000 mi. and above. That might slow the burn off of oil down to acceptable levels.

Good luck with it.

Sounds like you have some valve stem seals or valve guides leaking oil into the combustion chamber.

blue smoke indicates rings/bores are worn,time for a rebore.....

You may need a tune up if its been longer than 12,000 miles since the last one.

bluish is oil burning,if your car is smiking worse going up a hill that is piston rings,if you notice it worse coasting down a hill that is valve seals,but have you tried replacing the PCV valve yet,this lets the engine breath like you and me

It could be a oil control ring on piston or oil control valve on head or valve guides to worn or improper valve seal replacement or head gasket cracked head etc

you have bad seals in the valves or bad piston rings.

Did you re check for new codes after o2 replacement? Does the idle hunt (up and down)? Have someone check the EGR valve.

Replace the valve cover gasket, It should come with those rings.