Heavy wet-sumping

[desmo]

Hello all.

I have a fresh rebuilt M20 that is filling the primary chaincase with oil at an alarming rate.
My first suspect is the engine breather, a version unknown to me.
Year should be 1958 or 1959 since it has an alloy chaincase with dynamo.
Unfortunately the engine number has been removed...

So the question is:
does anyone recognise this breather assembly and is the mushroom plunger assembled as pictured?
Is there a spring missing?

Thank you for looking

Norman

breather M20.jpg

[Duncan]

If the plunger has a hollow centre it looks very much like the oil pressure relief valve (026133) that was fitted between 1960 and 62 between the oil filter tunnel and the timing case, I think someone has got inventive with it and modified the original breather.

[Andy.S]

Hi Norman
Club spares stock those 025525 RELIEF VALVE ASSEMBLY 1958-61 DYNAMO TWINS REPLACES 023260 FOR 57 MODELS.

[desmo]

And big thank you for your replys.
Will order a new assembly

Norman

[desmo]

Hi Andy.

Trying to order via the club spares service the search shows

"There are no items to display for '025525'"

What am I doing wrong?

Norman

[les ward]

025526
Page 8 of the twin engine section