pressure in my rocker cover

[Mr Don]

My wife's Moggy Humphrey has recently started "misfiring" so I have been methodically servicing the ignition and fuel system.

But today I noticed something I am not sure about. When I removed the oil cap to listen to the engine, tappets, with the engine running, I noticed quite a bit of pressure.

With my hand over the oil filler, it feels a bit like an exhaust pipe. But other than a good bit of mayo/oil and water condensation.

Could my head gasket be going? or something worse valve issue? Or is some pressure in the rocker cover normal and not related to the misfire.

Tomorrow I will replace the points, condensor, rotor and dissy cap.

Is pressure in rocker normal?

[bmcecosse]

No! It indicates a worn engine.....but can be mitigated to an extent by making sure the breathing arrangements are clear. Stub pipe on rocker cover clear? Rubber hose to carb clear? Or is it stuck into the air filter casing - coating the filter with oily crap?

[MarkyB]

Could my head gasket be going?

Absolutely, Do a compression check to be sure if you like.

[Mr Don]

Thanks guys,
I could do without striping the head this weekend.

Ignition and dizzy, tomorrow to trace the intermittent misfire. Then ensure engine oil breather tubes clear.

[bmcecosse]

Seriously - head gasket has nothing to do with rocker cover pressure........

[kennatt]

unlikely,but it could. If the gasket was blown between the cylinder and an oilway hole,but I've not seen it,usually between cylinders