Oil Smoke

[Bowtie Mafia]

I recently rebuilt the motor in my '87 GN. I now have 500 miles on the rebuild. I took it in for an emissions test where they failed me. I have visible oil smoke coming out the tailpipes. Any thoughts what might be causing it? I have asked a few friends they recommended checking the PCV and the turbo. Both are new, the PCV is connected and it is a new Precision 5831 Turbo. Thanks.

 

[turbo nasty]

Turbo, valve guides/seals, rings, pcv, etc

 

[dr_frankenstein]

what kind of rings did you use in the rebuild?

 

[Bowtie Mafia]

I'm not sure what rings were used. It doesn't say on the invoice from the machine shop. Getting a hold of the guy is a real pita.

 

[dr_frankenstein]

hmm.... interesting, has it always drifted a little smoke or is it just blowing smoke? there could be soo many variables...............

 

[Bowtie Mafia]

It's a steady smoke and it increases as the rpm's do.

 

[turbo nasty]

Plugs oily?

 

[Buick Mark]

Bet theres no seals on the exhaust valves. My GN did the same thing, the last time I had the engine out, I had new "non stepped" exhaust valves installed, and had the guides cut for seals. I dont know why Buick didnt do this and why they saw fit to omit seals for the exhaust valve guides.

 

[Bowtie Mafia]

The plugs aren't super oily. A little around the top of the threads, farthest away from the spark.

 

[Bowtie Mafia]

Is there a way to check exhaust valve seals without taking the whole thing out again?

 

[turbo nasty]

So if plugs have no oil signs in the combustion chamber and your crop dusting out the tail pipe i would look for oil leaking into turbine.

 

[Bowtie Mafia]

Awesome. What is the best to check that?

 

[turbo nasty]

In a nutshell pull turbo...pull elbow...etc should be dry on inlet to turbine and oily on exit.

 

[Bowtie Mafia]

I had a little more time today. I pulled off the down pipe, there was a little oil. But I also pulled 5 spark plugs, cylinders 4 & 5 were covered with oil inside. A compression test measured 120psi on all cylinders (I didn't test #6). Is this a sign of valve guides?

 

[Buick Mark]

Do a leakdown test

 

[bison]

It takes a very small amount of oil to cause visible smoke. I'd check the intake valve seals and manifold to head seal first. Areas of high vacuum that could potentially pull oil into the intake.

 

[TurboTdr3.8]

Mine did the same thing and it was a bad pcv valve . I checked the leakdown and it was fine on all cylinders so I looked elsewhere .