SHELBY GT 350 Member
Joined: Sep 2010
Likely bad news here, in the form of bad compression.
Try the Dollar Bill test- Start the engine, remove the oil fill cap, and hold a bill of your favorite denomination over the fill spout. Does it blow up and away from the fill spout, or is there a light amount of suction holding the bill in place?
If it blows up and away, this would be a strong indication of bad compression via compression rings on the piston. Follow up with a compression test and cylinder leakdown test on any poorly performing cylinders. When you perform the compression test, when you get a low reading at a particular cylinder, the quick and easy way to diagnose the lack of compression being due to a bad ring is to put about a teaspoon amount of motor oil into the cylinder and then repeat the compression test at that location. If you get better numbers with the oil in the cylinder, it would more or less confirm the lack of compression is due to the piston ring. If it stays pretty much the same, a leakdown test will confirm if it's a valve and which one in particular.
What's happening essentially is the unburnt air/fuel mixture in the combustion chamber is escaping into the crankcase on the compression stroke, aka 'blowby'. That would be why you smell gasoline in the oil and also explain the oil consumption you're experiencing.
2001 GT Convertible
All the usual bolt-ons 1967 Coupe
200 I6, C4