pdxRX7

I have seen reference to the term carbon lock. Can someone please explain this term to me. Thanks

I am told that I have no compression on one rotor, yet there is no smoking or leaks and the car starts every time, but runs very rough and has no power.

Any explanations OTHER than a blown rotor?

It is an 88 SE.

rgordon1979

iTrader: (3)

carbon builds up inside the combustion chambers and can eventually cause an apex seal or side seal to stick, thus causing you to lose compression. (this is why everyone on here says to wind your engine up once a day or so, to clear the carbon out) You would not see smoke unless your oil seals or water seals are bad/going bad.

Project84

Carbon lock is when the carbon builds up and prevents the rotor from moving, thus the engine won't crank. Hence the word locked. If you take the main crank pulley and spin it counter clockwise by hand,(or take the starter off and spin the flywheel backwards with a screw driver) it will reverse the travel of the rotors and move the apex seal away from the carbon that is wedging it. Its like chocking a tire, except the carbon chocks the apex seal seizing the motor. If your motor cranks, it isn't carbon locked. If you have no compression, you probably broke a seal, meaning it will need to be torn down to get the rotors out to replace the seal(s). Bad news (or worse, depends on how you look at it) broken seals tend to damage the rotor housing causing it to have to be replaced as well. Or the problem may be that the engine has so many miles on it that the housing is worn enough that the seals don't seal well enough to maintain compression, but again, that entails teardown and rebuild.