MG Car Repair: oil blow by, crank case, 3000rpm

Question
The last three drives I have taken over 3000rpm with my 78 mgb have ended with oil blowing back through the breather tubes into the weber carb. Re-routed a hose through the carbon cannister but same problem.  Oil pressure has always been at 50# unless hot and idling.  I've put on maybe 5000 miles since I last checked compression three seasons ago.  Any suggestions?

Answer
Hi Dan,
Blow-by has nothing to do with oil pressure. It has to do with the piston rings. Run a compression test (throttle open) and write down the results of each cylinder and then squirt about 4 or 5 squirts of engine oil into a cylinder (about a tablespoon of oil) and run another compression test (throttle open) and you will see an increase in compression but it should not be any higher than about 10% to 15% higher. If it is a lot higher then you have a ring problem on that cylinder.

Crank case pressure only comes from blow-by of the combustion going past the rings.

Howard