I have a 1995 civic. Compression is about 160 on all cylinders. Recently replaced head gasket, valve seals, adjusted valves. Runs good. MPG's lower than it should be, about 25. The engine smokes terribly and uses about a quart of oil per week. Usually, when burning oil, compression is low, but that's not the case on this motor. There's also an oil leak on the back side of the motor around the alternator. Can't figure out where it's coming from. The head gasket and valve cover are not leaking, but I have oil all around the back of the motor by the first two cylinders.
Again, it runs great, but going through a lot of oil and gas mileage not what it used to be.
New plugs, timing is perfect, no codes. I'm puzzled!

 

If the smoke out of exhaust pipe is oil smoke and it didn't smoke like that before the work conducted, you may need to review valve stem seal installation.

 

Smoke that is worse when you floor it and keeps going as long as you stay on the gas is going to be from the rings. Especially consider that if there is evidence of sludge in the engine because a previous owner (not you, of course) neglected to change the oil often enough.

For the leak, clean all the oil off and watch closely for where it first reappears. It could be from the filter or the pressure switch, or a crack in the outside of the head, but most likely, it's the valve cover gasket. There isn't any internal oil passage near that area other than the main one in the center of the block (where the switch is).

 

The oil leak is most likely comming from the oil sending unit located on the back of the engine. I had the same problem and couldnt find it forever until a friend told me they leak from there commonly

 

I have replaced the sending unit an cam seal and valve cover gasket and distributo O-ring and the leak is still very persistent and I can't tell where it's coming from even when I clean it off I can watch for an hour and it won't leak but as soon as I drive it it pours out so the next time I look under the hood oil is everwhere

 

I had this leak and after replacing it I still had it spraying out but after puting some teflon tape it is just fine now.

 

Dangit Jim, I'm a doctor not a mechanic. But I just redid the cylinder head on my '95 Civic EX 130K miles to give to my daughter (most of us doctors are overconfident about our skills in things unrelated to doctoring). The car started and passed inspection but over the next 300 miles it started blowing lots of smoke and using about a quart of oil per gas fill up (200 miles). It sort of looks like a crop duster going down the road...

In my day job, I do lots of research and if someone is sick and I can't figure it out I go to the books. This is what I did in this case. I started thinking it might be the PVC valve but a number of people notice this same problem after doing the cylinder head. I don't like coincidences... I like cause and effect.

I went out the the car and really studied it over and found that I had failed to reconnect the hose that goes from under the intake manifold (just beneath the PVC valve) back to the black box thing on the crankcase. It is really hard to see unless you jack the beater up and shine your light up to where the oil filter is--it's right next to it. There was oil dripping out of the crank case down to the oil pan. I reconnected the hose and immediately there was much less smoke (but not none at 4000 RPM)! Then I checked the PVC valve with a pair of pliers for the click and got none so I think it needs replacing too. I am taking him out for an hour spin on the highway to see what happens tomorrow.