99bluefirebird

iTrader: (8)

So my car burns about 1qt every 1000 miles or so. Also some black smoke out of exhaust under hard acceleration. And if I pull the dipstick I can get some smoke if I blip the throttle. So I assume my rings are bad and something is sloppy in the seal. But wouldn't all three of the rings have to be bad for the oil to get into the combustion chamber, then out the exhaust. But wouldn't the burnt oil also have to get into the crankcase to present as smoke?

Lt1Porsche

iTrader: (6)

What kind of oil are you using? how many miles on the car?

3.4camaro

iTrader: (1)

the ring on the bottom is designed to keep oil on it at all times. It helps the other 2 rings with friction against the cylinder walls.

Ohwell, time for a 402.

99bluefirebird

iTrader: (8)

How would the bottom ring keep oil on it all the time, is the oil port in the block setup along its travel? And I still don't get how burnt oil could get into the crankcase and exhaust to cause smoke at both locations? Would the valvetrain play any role in this?

99bluefirebird

iTrader: (8)

to the top

ArcticZ28

iTrader: (14)

If your rings aren't sealing well, the pressurized (and now exploding) gases from the combustion process will blow past them and into the crankcase, building up pressure in the crankcase. Now, that it is in the crankcase, it must go somewhere, which is why we have PCV. This relieves this pressure and vents the fuel/oil residues carried within this pressurized air and recirculates it back into your intake to be burned again (if you have the stock PCV) and not vented into the atmosphere.

eallanboggs

iTrader: (1)

The next time you're at a NHRA national event go to the Top Fuel pits and ask someone who works on the bottom end that question. You'll find out about blowby big time. Top Fuelers change their oil twice on evey run due to blowby. That's two cases of oil every 1/4th mile. Do a compression or a leak down to check your rings.