Hi-

Ran a compression test today on my 305, which suddenly started burning oil continuously the other day (has 150K on it).

I was expecting to find a low cylinder because the only thing I could think of as to how my engine would suddenly start smoking would be if a ring broke. However all my cylinders are running between 180-190psi dry. Squirting oil and doing a retest would raise the PSI value by 15-20 across the board. While that would indicate worn rings (duh), it doesn't explain why it would start smoking all of a sudden.

Some other information- I do know my valve stem seals are worn as before it would puff blue smoke on startup for only the first 5-10 seconds, then clear off. Also, when I pulled the plugs they were pretty dark- almost black so I'm apparently running rich. However none of the plugs exhibit oil fouling.

Also, someone had previously suggested to me that one of my intake manifold gaskets may've gone out (the engine idles poorly now- it idled fine the day before this happened) and is sucking oil that way. Is there anything else I could check?

Again, thanks!

 

intake gasket seems reasonable, look for vacumn leak, check pvc system

 

By the way, what readings would be considered normal for a stock 305 with a fresh rebuild?