So I have a My00 ap1 with 142k miles. I recently rebuilt the head becuase my exhaust valves had so much carbon build up they weren't sealing anymore. So I replaced the valves and valve seals and gaskets and whatnot. But my problem now is I'm burning an absurd amount amount of oil. I know ap1's burn alot. But I drove up to thunderhill raceway this last weekend(260 miles roundtrip) and burned 2 quarts of oil just driving on the freeway. The car doesn't smoke just driving normal but if I put it in vtec a huge black/grey cloud shoots out of the back. My rear bumper and mufflers are covered in black soot. And if I pull the dipstick or oil cap while the engine is hot a grey smoke kind of whisps out. Also my intake manifold is fairly clean inside so I don't think it's my pcv. I'd be ok with 1 quart every 1000 miles. But 2 quarts in 260 is too much and I don't know what could cause it.

 

Most probably it's blowby by your description, you have combustion gases escaping the piston rings.

 

You might want to start by doing a compression test. Also, see if you continue to burn at that rate. If you took some hard turns while accelerating you could have sucked a lot of oil through your PCV. You can't assume anything in 260 miles.

 

Well I had also done a trip a few days before to Tahoe (320 miles) and that burned 4 quarts. Also I forgot to mention I did a compression test I got #1 200psi #2 200psi #3 200psi #4 230psi.

 

The only thing touched was the head? New oen valves and stem seals?

 

I didn't touch the bottom end. The cylinder walls looked good. There wasn't any obvious scoring on them. And the seals are oem. The valves are Brian Crower stainless steel.

 

Sounds like valve seals and/or guides are worn out. Does the car blow out a lot of smoke on deceleration? Like using lower gears to slow down from a long drive?

May want to go to heavier weight oil, in the meantime, while waiting for diagnosis and fix.

 

The valve seals are brand new. And the only time it smokes and I notice it is accelerating in vtec. The exhaust valve guides had some wear on them considering how old the engine is. But it wasn't enough to be worried about. I was using Mobile 1 10w30. But I switched to castrol gtx 10w30 after the head rebuild.

 

The car had sat for two years. Is it possible the piston rings have build up and are stuck?

 

Didn't you say you have good compression? I guess the oil rings could have lost flexibility.

If you run the car under 6K, you get no oil consumption? Or you get same oil use, just no smoke?