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Thats not a good sign.

The engine shouldn't lose oil througt the breather hose. A few drops each 1000k is ok, but not that much that its readable from the dipstick.

Is your valve cover ok?
I mean is the labyrint inside the cover still there or did somebody remove it for a good cleanup?

Yes
I admit I pushed it hard yesterday (and today!)
But the mechanic said it is not a big deal, it might be a flange

I don't really know.
I will have this checked

BertjeConti wrote:Thats not a good sign.

The engine shouldn't lose oil througt the breather hose. A few drops each 1000k is ok, but not that much that its readable from the dipstick.

as bertjeconti said, a few drops and a small amount of smoke is acceptable but not as much as you are saying! that burning way to much oil through the breather! check you have the right oil density for your climate and that the breather labyrinth filter is not missing, otherwise there most probably seems to be a problem with the internals of the engine...

Dammizi wrote:
... check you have the right oil density for your climate and that the breather labyrinth filter is not missing, otherwise there most probably seems to be a problem with the internals of the engine...

What does the breather labyrinth filter look like?

I forgot to take a pic, but I 'll post one here, a rather big oil spot appeared on the insulation foam exactly over (on top of) the fuel pump.
A friend with experience on M10 engines suggested it might be the Bakelite (plastic) part of the fuel pump where the pump connects to the engine.
I guess if that is the case, it might not be a big deal, a new flange might solve the issue

petroscf wrote:

Dammizi wrote:
... check you have the right oil density for your climate and that the breather labyrinth filter is not missing, otherwise there most probably seems to be a problem with the internals of the engine...

What does the breather labyrinth filter look like?

breather labyrinth filter is the foam like filter inside of the rocker cover between the cylinder head and the breather hose, sometimes this may get clogged up and instead of cleaning this is mistakenly removed which could cause a lot of oil splutter from the breather hose...

I 'll mention this to my mechanic tomorrow, thanks!

Dammizi wrote:...well I always thought that this was done due to emmisions regulations and controls in many countries, to reduce fumes escaping outside and especially into the cabin for drivers safety. in many countries it is mandatory that the breather hose is left connected to the intake manifold for emissions control. but here in Malta this is not controlled so many of us disconnect this to prevent filling the intake manifold with the oily fumes...

I was reading again your post...

Well, afaik the emissions are counted from the exhaust, no?
So which MOT would check if the breather is free to send oil fumes into the cabin? On the contrary, might not emissions be worst if oil is dropping in the inlet manifold and some of it burnt mixed with the fuel mix?

Also another question: I did not see any way to connect any hose to my engines inlet manifold -which is not the big normal downdraught one, but a small for side draught carbs
Unless you mean that this was reconnected by some way into the sump?

petroscf wrote:

Dammizi wrote:...well I always thought that this was done due to emmisions regulations and controls in many countries, to reduce fumes escaping outside and especially into the cabin for drivers safety. in many countries it is mandatory that the breather hose is left connected to the intake manifold for emissions control. but here in Malta this is not controlled so many of us disconnect this to prevent filling the intake manifold with the oily fumes...

I was reading again your post...

Well, afaik the emissions are counted from the exhaust, no?
So which MOT would check if the breather is free to send oil fumes into the cabin? On the contrary, might not emissions be worst if oil is dropping in the inlet manifold and some of it burnt mixed with the fuel mix?

Also another question: I did not see any way to connect any hose to my engines inlet manifold -which is not the big normal downdraught one, but a small for side draught carbs
Unless you mean that this was reconnected by some way into the sump?

On carburetted engine the breather hose is connected to the air filter box.
On fuel injected engines the breather hose is connected somewhere to the inlet system before the throttle valve.
In both cases where there isn't any vacuum and the fumes are sucked in the engine and burned.

Finally it seems it was the fuel pump
It let some oil pass through
Replaced now
If the problem continues, we will replace it by an electrical one

A friend suggested this

http://www.et-performance.com/

(search part: krank vent)

As I guess that oil fumes will still be there-at least for some time-even if/when fuel pump issue is sorted, might this be a solution?
I don't even yet know what this is exactly and if this (or similar) can fit on M10

Anyone with any idea on this?

Hi,

From your photos, it looks like your oil catch can isn't connected up fully, you should have another hose running from the outlet of the catch can to the intake, where those fumes will be burned and expelled through the exhaust.

Otherwise although you are catching the oil mist in the fumes, you are just venting the smell/fumes into the engine bay.

Dave.

davidvincent wrote:Hi,

From your photos, it looks like your oil catch can isn't connected up fully, you should have another hose running from the outlet of the catch can to the intake, where those fumes will be burned and expelled through the exhaust.

Otherwise although you are catching the oil mist in the fumes, you are just venting the smell/fumes into the engine bay.

Dave.

It seems I owe an update with some pictures here.
We have already done something here, not exactly what you said, but :





We connected the oil catcher's outlet to a hose and the other end of the hose to this:





It seems that this has led fumes further than air vents so I still smell them (!) but fewer now, as it seems they escape from elsewhere.
The problem is that oil still goes out from this little filter:



The engine's inlet manifold is of this type:



So I can't see where a hose coming from the rocker breather could be connected
May be the solution here should be to fit plenum type air filter box on the webers? instead of the current setup (which I have to admit produces perfect music to my ears...)
And then connect the hose coming from the breather to the plenum, so the fumes go inside there?

Now, about that fuel pump spitting oil (mentioned already above and/or in my build thread)
We replaced it but I can still see some oil "teardrops" - so that might mean that if rpm increase up to 6000+ like the other time we might have the same result?

maybe the solution here is an electric pump?

Yes that's a common solution, to add a little bike filter on the end - but if you're still getting oil out from that then the catch can isn't working, perhaps you need a more expensive baffled can?

But either way, that amount of blow-by shouldn't be expected on a rebuild engine - did you rebuild top and bottom of the engine or just the top/head?

When the engine is running, take the oil filler cap off and balance the lid back on loosely - does it blow off, or can you feel a lot of air rushing out?

I use an OBP http://www.obpltd.com/Alloy-Products/Catch-Tanks) catch can, but I have a 6cyl engine with a Weber Carb setup, with a K&N air filter - I had to adapt the base of a K&N to accept the hose from the catch can, so I have no fumes in the engine bay (or car) now.... but if you're still getting oily deposits after the catch can stage, then you need to consider what is causing it (excessive blow-by, or a too basic catch can, or both).