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MG MGF Technical - Why did I put my fingers in-side the thottle body?

Because now I am worried. I was checking the K&N air filter. So I disconnected the tube that links the filter to TB. I then inspected the inside of the rubber tube, clean, no issues. But then I had to go an stick my fingers in the TB, i.e. open the butterfly valve and feel inside the TB.

My fingers can out coated in black sticky stuff. Very thick, jet black with a petrol smell. More sticky than engine oil!

No I am worried - what is the black stuff?

PS: my fingers are now fine - fairly liquid to the rescue.

Steve Ratledge

Engine oil ;-)

You've stuck you fingers into what the engine breaths out and then recycles, if you are worried then you can clean it thru with carb cleaner, but I wouldn't worry.
Will Munns

Thank the 'tree huggers' for their campaign to clean up the world!

As will says - just clean it and dont worry.

Ted Newman

Thanks Will, <sigh of relief>

Why is this muck then recycled though the Tb and the inlet manofold etc?
Steve Ratledge

It used to be passed out into the atomsphere through a crankcase breather, now they pass it back into the engine to burn it !, it is supposed to be less polluting that way.
Mike (@home)

Basicly there is always some gas escape from combustion into the crankcase (blow by), and if left to build up this will force oil past the bearings and into the flywheel bellhousing, un thru the dipstick and thru any mating surfaces (bolt heads, ladder faces etc.).

A solution is to vent the pressure to the atmosphere, this has the effect of throwing a little oil out and any oil vapor.

A better solution is to vent the oil [vapor] into the airfilter, this means that any sticky stuff is burnt off, but this still leaves the crankcase at atmospheric pressure, so doesn't help stop leaks.

The K-series has two pipes, one runs from the airfilter, and the other from the inlet manifold, the inlet manifold sucks air out of the crankcase, this means that the whole engine runs at negative pressure, and any leaks suck air into the crankcase rather than alowing oil out.
Will Munns

Thanks for that Will.
Steve Ratledge

This thread was discussed on 05/04/2004

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