I got an " I told you so" from an engine builder I know. The Mobil 1 10-30 was thin enough so my lil 427 RAT ate it up like maple syrup. Switched back to Val 10-40 and no more smoke.
I have a "new" run-in 427 in my 67. Appox 15-20,000 miles when I bought it. Half way through life I figured by inspection of #1 rod and main bearing. I just put Mobil 1 synthetic in and really started moving oil. Espcially on the odd bank. Pulled all the plugs and they're burning well with minor residual oil fouling on the threads.
Swapped out the mobil 1 for std 10-40 and now my exhaust smells slightly rich due to the cam, but the burning oil smell is gone.
Also upped the thermostat to 180 from 160 which might've helped.
Net/net: use caution when using light synthetic oil in a run in motor. It could cuase it to start eating it. It surely did mine.
I have a "new" run-in 427 in my 67. Appox 15-20,000 miles when I bought it. Half way through life I figured by inspection of #1 rod and main bearing. I just put Mobil 1 synthetic in and really started moving oil. Espcially on the odd bank. Pulled all the plugs and they're burning well with minor residual oil fouling on the threads.
Swapped out the mobil 1 for std 10-40 and now my exhaust smells slightly rich due to the cam, but the burning oil smell is gone.
Also upped the thermostat to 180 from 160 which might've helped.
Net/net: use caution when using light synthetic oil in a run in motor. It could cuase it to start eating it. It surely did mine.