Oil breather

[FergusonFE35]

Hi again,
On opening the cover, this is what the flap inside the casting looks like. Other than it is complete, the spring holds the flap a millimeter off the hole. Should this be the case? Is there any other servicing which this will need? The car leaves a couple spots of oil when warm after a run which i expected, but want to make sure this is ok.
Thanks
David

[Tony Fearn]

Hello again David.
It's some time since I ran a 1927 Long Two, and I can't really remember what the inside of the breather looks like, but on my pre-wars, the vanes of the breather (which were upgraded to spring steel from vintage times) are 'tight' against the holes, so 1mm away in the case of your car doesn't seem correct. The leather flap should touch the holes to seal them, or so I think.

From the Pre-war service bulletin:-

Breather Valve This is a non-return valve which should be kept clean and in good order. It
allows air to escape freely from the crankcase but restricts the intake. A choked breather
valve causes a build up of air in the crankcase which forces oil to leak at the tappets, bearings
and dynamo. The depression should be sufficient to raise 12" or more of Redex in a
manometer gauge (glass tube resting in a container of Redex at ground level and connected
to a rubber tube fitted to the oil level indicator tube) or ¾" to 1" on a mercury gauge. This
should decrease from tickover as r.p.m. increases. The star stiffening plate should well
support the diaphragm and together with the oil drain hole be kept clean.
Oil drain holes exist at the base of the breather valve housing, the timing case, and the
crankcase rear cover plate. They should be cleared regularly with a long wire (not nail or pin
which might drop through).

This relates to the later breather valve, but the 'sentiment' is the same.

Perhaps someone will sketch what it should look like.

Regards,

Tony.

[Brucegirvan]

I have a 1930 with the metal star breather valves and a 1929 with exactly your spring and leather section cover. If you run the engine with the cover of the breather off (exactly as you have photographed it) you will see the flap moving back and forwards with no issue. IT is vital that the small breather hole (at 6 o’clock on the breather face) is clear the whole way back to the filling neck. I use a copper strand and check it every 6 months or few hundred miles.

If you take the flap off (remove the spring retaining screw carefully) you may find a gauze sheet there as well. I cleaned mine in petrol to clean it up. My leather was torn along the bottom edge. You can lightly separate the metal clamps and I then used a bit of M&S slipper leather cut to size, gently nipped the metal clamps to it, and she runs very nicely. Yes, you do still get a drop or 2 of oil, though not much and certainly very little compared to no breather valve.

I hope that helps.

Bruce