Blue smoke after warm up

[artpeck]

Situation: Low mileage engine (under 40k miles documented as this was in the family). 73 S III. I have been restoring it bit by bit and it has been running now for awhile. Compression is perfect in all cylinders, right on the green book. Starts and runs well. But when it is warm it starts to smoke with blue smoke so presume it is oil. My question is where should I start to try to track this down? It's not the rings and cylinders given the compression. This is getting into territory where I really don't have instincts so any help I appreciated. Thanks

[albersj51]

You're absolutely sure its blue and not black, as in fuel?

[cedryck]

Gas or diesel?

[kwells]

Blue smoke is burning oil. Its either leaking valve seals or worn rings allowing blow-by. Since you say the compression is good, Id assume its the valve seals but I dont think perfect compression absolutely guarantees no oil is sneaking past 42 year old rings.

[Jim-ME]

Blue smoke is burning oil. Its either leaking valve seals or worn rings allowing blow-by. Since you say the compression is good, Id assume its the valve seals but I dont think perfect compression absolutely guarantees no oil is sneaking past 42 year old rings.

If you are sure it's blue smoke I totally agree with kwells assessment.
Jim