I have a 91 turbo and it is blowing smoke out of the exhaust. I think the rings are bad. Do any one know what the compression in lbs suppose to be in the cylinders?

What color smoke.? White is coolant. Blue is oil. And black is unburnt fuel.

Not white, its not the coolant, but its alot of oil on sparkplugs and they was just changed. They are black now and I dida compression check and its at 120 in two of the front cylinders 110 in the other. Havent checked the back yet. The smoke looks grey.

Your compression psi should be 120 psi to 160 psi. For a stock 8:1 compression ratio.

That's on the lower side of what it should be.

Sounds like oil. Add a little oil in cylinders and re do check. If numbers stay the same your rings are probably ok. If numbers rise then you do have a ring issue. I suspect valve guide seals. Just had to replace the ones in my 91 3000 gt for smoke issues.

If it was mine and the numbers stayed the same with the wet compression check I would pull the heads have valve guide seals installed and have the valves checked and re seated. Doing this should bring your psi numbers back up to the 160 range.

Ok thanks for the advice. So you think the seals in the heads might be bad if the compression stays the same?

If numbers stay the same typically mean that the rings are ok. And if they are ok that leads me to believe that the smoke is coming from the seals and that the low compression numbers is coming from the valves not seating properly due to carbon build up. Having the valves checked and reseated will cause the compression to come back up.

Thanks!!!!

I agree these motors are not known for bad rings.If the engine has super high miles they usually will spin a crank shaft bearing first. Check your seals and guides first.