Blue Smoke when leaving stop, help diagnose

straws said:

Hey all,
Just bought a 1992 Vert with a 2.3 for my daughter (First car). On driving it home my wife said the tailpipe was smoking blue when taking off from any stops and when I let of gas then accelerated.

Does this sound like a valve seal problem, or a ring problem? If valve seals, can they be changed while the head is on the car?

Thanks in advance.

Click to expand...

anytime you either lift off the throttle, or let a car sit at idle, vacuum is at it's highest. If the car smokes during either of these times (or both) Then the seals or valve guides are the culprits.

While umbrella seals can be changed "on the motor" you'll have to pull the head to fix the latter.

Smoking under acceleration, is almost always a sign of poor ring seal.
Unscrew the oil fill cap while the engine idles and see how much smoke puffs out of that hole. Depending on how much smoke is coming out of there is an initial telltale that you have a worn out engine.

If that looks bad, an engine leakdown gauge set is the next step, and it will tell you everything. The set is comprised of two gauges and a regulator. One side of the kit is screwed into a cylinder spark plug hole, the other side goes to the supply of compressed air. The regulator can be set to supply between 75-100 psi of air to that cylinder, (one gauge) and the other side gauge will detail the percentage of that cylinder leakage.
in addition to the gauge reading 30% or higher (all bad) You'll more than likely hear air leaking both into the crank case and into the intake past the valve if the valves are not sealing properly.

Obviously not something a shadetree mechanic has at his disposal, but maybe auto zone rents it.

You could also use a standard compression tester to see how low the compression has dropped, and to determine whether there is a cylinder lower than the others. But unlike the leakdown kit, it will not tell you where the lower compression in a suspect cylinder is going.

I brought home a 89 4 cyl notch last summer, and it smoked so bad when I decelerated, that a cloud of smoke would catch me if I came to a stop at a light.
That engine is sitting in a corner of my garage now, waiting for me to decide on what to do w/ it.

Your welcome in arrears.