Morris Minor Owners Club

Has anyone used either Wynn's or Redex,s oil stop leak and if so do they work as i have the common / classic crank seal oil leak !

doubt if these miracle cures work
check your breathing system

Don't waste yer money - as above - sort out the engine breathing...

ok thanks so as far as a novice goes, what should i be looking at / for?

The pipe from rocker cover to intake system must be clear - not blocked. When the engine is hot - take the oil filler cap off and rev up - is there a plume of smoke/fume ???

For my oil leak Roy kindly advised me at the National Rally that:

• I find a oil filler cap that's vented/breathes (this was achieved for £3 at the rally but are available for ~£5 from parts suppliers).
  
  And/Or
  
  Use a longer pipe to go from the rocker cover breather to point down (with the chest swan-neck breather) instead of going into the air-filter housing as it has a very small aperture.

I no longer have leaks, the MOT man approved as all involved expected an oil leak as an advisory. ;)

Not this Roy..... The breathing cap now means you are breathing in carcinogenic/smelly/oil fumes. Good luck with that...

I forgot to mention this was a temporary solution to get home from the rally before further investigation could be carried out.

Cap aside, is venting the air from the rocker cover downwards with the swan-neck breather viable in the long-term? What do the chaps with the fancy pancake air filters do?

No - you must suck the fumes into the intake system - very best is the PCV valve system fitted to later engines, next up is the later carb with a vent tube (for sucking) in the side - and poorest of all is the original system where the fumes are sucked into the air cleaner where they plaster the paper filter with oil gunge. The real answer is to overhaul the engine.

If I may join this discussion - I have oil dripping from the pipe that exists the side cover of the engine.
What can I do to fix this?

Thank you

Try fitting a different cover, the type with the canister, then pipe it to the vacuum connection on the carb. It will draw a slight vacuum on the engine and burn off all those nasty fumes.

Is the engine badly worn? Hot engine idling - remove the oil filler cap - rev up....is there a plume of smoke/fume ??

Check the breather pipe from the rocker cover is clear - take it off and clean it all out... But the 'can' idea mentioned above will help - if the 'can' is not blocked with gunge..

A question on the fumes aspect, as our 1969 pick-up is getting decidedly smellier - especially on over run.

It has a vented oil filler cap, pipe from rocker cover to side of carb and a pipe from tappet chest, venting to air under the car.

All pipes have been cleaned out and the rocker cap checked and all are clear. I've tried running both rocker pipe and tappet vent pipe, via a Y junction, in to the side of the carb and there was a slight improvement.

No smoke coming from rocker cover, nor any blue smoke from exhaust.

Do I need a vented oil filler? I thought I did to allow the crankcase breathing process to work but now I'm wondering if fitting a non-vented cap and having both "exit" pipes connected up to the carb would a workable option?

Comments welcomed.

The vented cap is the cause of the smell! Fit a proper sealed cap - there's no way you want to be breathing these fumes. You must suck the fumes into the engine and burn them!

So, fit a sealed cap then route both rocker pipe and tappet chest pipe into the side of the carb to burn off the fumes. I'll give that a go as I certainly don't want to inhale them!

I suppose I was assuming that the vent was required to assist with the breathing and that air was drawn in rather than fumes allowed out and that I'd cause a problem by having a sealed cap. It begs a question as to why there are sealed and vented caps?

Mixed up thinking! NO modern engine has a vented cap.... They ALL have a system of taking away the crankcase fumes. The best answer is the PCValve- otherwise perhaps one pipe to the carb and the other to the air filter intake?

NO modern engine has a vented cap

May well be true, but they all have a fresh air inlet as part of the 'positive crankcase ventilation (PCV)' system - it cannot work without air coming into the crankcase to replace the fumes being drawn out.

This is an very old topic, and does not improve by repeating the same, mistaken, comment about never using a vented oil filler cap on an A-Series engine.

The A-Series engine design is very simple - early engines either have the tube running down from the tappet chest cover or a connection from the rocker cover to the air filter and both must have a non-vented cap. They rely on getting rid of the fumes coming OUT of the crankcase - no connection with either the later A-Series design or any modern engine design.

Later engines used a 'positive crankcase ventilation' (PCV) system with either the inlet manifold PCV valve, or the oil separator canister on the tappet cover/timing cover with the hose feeding directly into the port on the side of the carburettor. All these engines had a vented cap to allow filtered air to be drawn IN, not fumes OUT. If the closed circuit system has fumes coming out of the filler cap, there is something wrong with the system - the solution is to fix the problem, not bung up the only way IN for the fresh air!! It most certainly will not work if you do.

Ah, thanks for the fuller explanation and I can now understand what's going on: I have the earlier engine breathing arrangement, before PCV, to which someone has fitted a later vented cap.

So not mixed up thinking but a confusion of caps!

Thanks guys.

Modern engines are SEALED - no air inlet - they work with a slight vacuum (controlled by a PCValve) to remove all the fumes. If I take the filler cap off my modern there is suction on the filler pipe. That's what to aim for on the A series. Vented cap leads to fumes in the car... No need to let air in - the system will simply take away any fumes in the crankcase, it doesn't need a flow of air.

If the engine is sealed then it will try to draw air in is through the crankshaft scrolls - no fumes no leaks