i was thinkin i needed rings cause my car was smokin like hell and had a bad compression test on one cylinder. anyways i got the head off and my valves are caked with black **** all down one side and the others are completely white. i dont know if when the car turns off if they're supposed to seal but four of them were about a quarter inch off the head. before i tested everything i was smokin like hell and barely runnin and you could hear a knockin sound in the exhaust at the rear of the car. could the head be the problem or still sound like rings??
have the head checked for level milling it may be warped if it has ever overheated..
thats the oil being burned...its either bad rings thats why ur burning oil or bad valve guides...a ring will fail first before the guide
It could be the valve seals failed and the oil ran down the valves and put multiply layers of oil, which will burn and leave a cake-like carbon on the valves. This would prevent the valves from sealing, thus less compression. You did not mention how many miles were on the engine. If it has over 175,000 miles you need to rebuild the motor, including the head.
Bad rings cause excess blow by in the crankcase causing vapors (heavy) to come from the dipstick tube as well as the valve cover. I can smell the exhaust smell in the breather vapors not just oily smell. Valves mostly cause smoking out the tailpipe as oil enters the cylinder and burns. excess oil usage is common as well. A compression test will indicate bad rings as one or 2 cylinders will read much lower on the gauge. valves can be seen as bad compression as well but often show more in the leak down in the gauge. the condition you stated of the valves is from oil entering the cylinder heads and burning. this is usually valve guides.
