'73 MGB; smoke from engine compartment,..

Hello, the latest is some kind of pressure build-up inside the valve cover. It seems as if this pressure is forcing oil out around the
cover seal then the fan sprays it over the hot bits making smoke roll out of the engine compartment. I can take the fill cap off, place my hand over it for a few seconds and when I take it off it makes a noticeable chuffing sound. I tried tightening down double gaskets with and without goop but no luck. The smog pump was taken off years ago and some kind of ports on the valve system were plugged off. There is smoke trying to escape from the carbon filter canister near the passenger side firewall and whatever electronics controlled it's outlet have snapped off and disappeared. A disgraceful, viscous gray smoke rolls out from the tailpipe with plenty of water dripping. If this car ever had a catholic converter it's been cut out. Factory carbs replaced by weber 36something down draft and set once 25 years ago. No smog test where I live. Has anyone encountered a plugged engine syndrome before? ta-rah.
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on the buses wrote:

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??
r
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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.
2nd thought. Is the engine in rough condition, could it be badly scored bores or broken ring/s pressurising the crankcase.
Oh & by the way Tks for your query gave us all a laugh The Word is 'catalytic'
P
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wrote:

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,..
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Converts water to bioethanol perhaps? :-)
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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
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wrote:

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.
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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.
I had the same problem on my 76 MG Midget and after pulling the head off I decided to do a complete engine remanufacture. I cost me around two thousand for parts and machine work but the engine is better than when it left the factory. I too have a weber down draft, eliminated the smog pump, by passed the carbon canister, and I do pass smog tests

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Thank you, Neil. I remember the term now. This past summer I noticed there's an unignorable increase in lifter noise and reduced power when going uphill. I adjusted the valves but no improvement. I'll try to retorque the head first, I suppose, just for practice. I did a full rebuild perhaps 12 years ago and spent roughly $1000 in parts and service which included a professional valve grind. I don't think there's 30k miles since then as it sits all winter and runs perhaps 4 months a year where I live. I've also had a problem with the choke cable which may be interfering with the throttle on the weber carb. Is there a picture anywhere of how this is supposed to be arranged? Hoping that's part of my smokey output. Also, is there a conclusive test for blow by? I have the green Bentley manual for my model.
wrote:

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