'73 MGB; smoke from engine compartment,..

Pressure build up.

All the hoses clear so the inlet manifold sucks the excess back into the motor. These do deteriorate colapse, fill with crud, etc. EGR clear??

I dont think you can seal the smoke in, better to identify the source of the problem.

First thought, It could be a simple case of head gasket failure. Look for coolant loss or oil under the coolant filler cap. Worst case would be coolant water in the crankcase oil.

Oh & by the way Tks for your query gave us all a laugh The Word is 'catalytic'

Check the charcoal cannister in the corner of the engine compartment. You can replace the charcoal with fish tank filter charcoal. The cannister or one of the hoses leading to/from it may be clogged.

Dan D '65 B '76 B Central NJ USA

Thanks, that's what I did 8 years ago and I'm sure it's time to renew it. I disconnected the inlet to the canister just to see if the problem would go away but it did not seem to. I'll try and pull the valve cover this week and see if that rear tube fitting that feeds the cannister line is plugged.

Groan, well I was low on coolant. That would explain the tailpipe steam. No cream in the oil cap yet.

Impossible, I rebuilt the engine myself,.. twice.

Ah, a jest from the us radio program, "car talk". A minister calls in with an exhaust problem concerning his catholic converter,..

Converts water to bioethanol perhaps? :-)

What you are experiencing is excessive "blow by". The piston rings and cylinders have worn to a point where they can no longer hold all the combustion pressures and a portion of the exhaust gas leaks past the rings into the crank case pressurizing it and forcing oil out between the gaskets and sealing surfaces. Some options exist to sovle problem: 1. Rebuild engine or at least put new rings in it 2. Run a tube from the valve cover down past the tranmission the vent the blow by past the passenger compartment. 3. Due to water dripping out the exhaust you may have a damaged head gasket, replace it.